LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH v2 00/14] tracing: Add triggers to trace_marker writes
@ 2018-05-14 20:58 Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 01/14] tracing: Do not reference event data in post call triggers Steven Rostedt
                   ` (13 more replies)
  0 siblings, 14 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

A few people have asked for this in the past, and I finally got around
to implementing it. What this does is to allow writes into trace_marker
to initiate a trigger.

The trace_marker event is described in:

 tracefs/events/ftrace/print

Thus the trigger file is added there:

 tracefs/events/ftrace/print/trigger

As there's already a "hist" file there, everything appears to work
just like any other trigger to an event. See the last patch for
documentation on how to use the triggers to a trace_marker write.

By the way, the patch:

  tracing: Prevent further users of zero size static arrays in trace events

May prevent your kernel from building if you include Xen. You will need
to add this patch to make it work.

 http://lkml.kernel.org/r/20180509144605.5a220327@gandalf.local.home

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
ftrace/core

Head SHA1: a3762cfaa4e4b141aa53d3053f38a9cdd47ea49b


Steven Rostedt (VMware) (14):
      tracing: Do not reference event data in post call triggers
      tracing: Add __find_event_file() to find event files without restrictions
      tracing: Have event_trace_init() called by trace_init_tracefs()
      tracing: Add brackets in ftrace event dynamic arrays
      tracing: Do not show filter file for ftrace internal events
      tracing: Add trigger file for trace_markers tracefs/ftrace/print
      tracing: Have zero size length in filter logic be full string
      tracing: Prevent further users of zero size static arrays in trace events
      tracing: Allow histogram triggers to access ftrace internal events
      tracing: Document trace_marker triggers
      ftrace/selftest: Have the reset_trigger code be a bit more careful
      ftrace/selftest: Fix reset_trigger() to handle triggers with filters
      tracing/selftest: Add selftests to test trace_marker histogram triggers
      tracing/selftest: Add test to test hist trigger between kernel event and trace_marker

----
Changes since v1:

 - Fixed comment about length (Masami Hiramatsu)
 - Added note about ->reg() requiremet (Namhyung Kim)
 - Added fix for r->len (Yann Ylavic)
 - Added fixes for reset_trigger in ftrace self test
 - Added self tests to test the trace_marker triggers

 Documentation/trace/events.rst                     |   6 +-
 Documentation/trace/ftrace.rst                     |   5 +
 Documentation/trace/histogram.txt                  | 546 ++++++++++++++++++++-
 include/linux/trace_events.h                       |   3 +-
 include/trace/trace_events.h                       |   1 +
 kernel/trace/trace.c                               |  19 +
 kernel/trace/trace.h                               |   9 +-
 kernel/trace/trace_entries.h                       |   6 +-
 kernel/trace/trace_events.c                        |  36 +-
 kernel/trace/trace_events_filter.c                 |  23 +-
 kernel/trace/trace_events_hist.c                   |   2 +-
 kernel/trace/trace_events_trigger.c                |   6 +-
 kernel/trace/trace_export.c                        |   9 +-
 tools/testing/selftests/ftrace/test.d/functions    |  23 +-
 .../trigger/trigger-trace-marker-synthetic.tc      |  88 ++++
 .../ftrace/test.d/trigger/trigger-trace-marker.tc  |  49 ++
 16 files changed, 790 insertions(+), 41 deletions(-)
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 01/14] tracing: Do not reference event data in post call triggers
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 02/14] tracing: Add __find_event_file() to find event files without restrictions Steven Rostedt
                   ` (12 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0001-tracing-Do-not-reference-event-data-in-post-call-tri.patch --]
[-- Type: text/plain, Size: 3605 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Trace event triggers can be called before or after the event has been
committed. If it has been called after the commit, there's a possibility
that the event no longer exists. Currently, the two post callers is the
trigger to disable tracing (traceoff) and the one that will record a stack
dump (stacktrace). Neither of them reference the trace event entry record,
as that would lead to a race condition that could pass in corrupted data.

To prevent any other users of the post data triggers from using the trace
event record, pass in NULL to the post call trigger functions for the event
record, as they should never need to use them in the first place.

This does not fix any bug, but prevents bugs from happening by new post call
trigger users.

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/trace_events.h        | 3 +--
 kernel/trace/trace.h                | 4 ++--
 kernel/trace/trace_events_trigger.c | 6 ++----
 3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 2bde3eff564c..d1c442d9bd85 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -435,8 +435,7 @@ event_triggers_call(struct trace_event_file *file, void *rec,
 		    struct ring_buffer_event *event);
 extern void
 event_triggers_post_call(struct trace_event_file *file,
-			 enum event_trigger_type tt,
-			 void *rec, struct ring_buffer_event *event);
+			 enum event_trigger_type tt);
 
 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file);
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6fb46a06c9dc..24b666891eaf 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1334,7 +1334,7 @@ event_trigger_unlock_commit(struct trace_event_file *file,
 		trace_buffer_unlock_commit(file->tr, buffer, event, irq_flags, pc);
 
 	if (tt)
-		event_triggers_post_call(file, tt, entry, event);
+		event_triggers_post_call(file, tt);
 }
 
 /**
@@ -1367,7 +1367,7 @@ event_trigger_unlock_commit_regs(struct trace_event_file *file,
 						irq_flags, pc, regs);
 
 	if (tt)
-		event_triggers_post_call(file, tt, entry, event);
+		event_triggers_post_call(file, tt);
 }
 
 #define FILTER_PRED_INVALID	((unsigned short)-1)
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d251cabcf69a..cc4148bfc01a 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -97,7 +97,6 @@ EXPORT_SYMBOL_GPL(event_triggers_call);
  * event_triggers_post_call - Call 'post_triggers' for a trace event
  * @file: The trace_event_file associated with the event
  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
- * @rec: The trace entry for the event
  *
  * For each trigger associated with an event, invoke the trigger
  * function registered with the associated trigger command, if the
@@ -108,8 +107,7 @@ EXPORT_SYMBOL_GPL(event_triggers_call);
  */
 void
 event_triggers_post_call(struct trace_event_file *file,
-			 enum event_trigger_type tt,
-			 void *rec, struct ring_buffer_event *event)
+			 enum event_trigger_type tt)
 {
 	struct event_trigger_data *data;
 
@@ -117,7 +115,7 @@ event_triggers_post_call(struct trace_event_file *file,
 		if (data->paused)
 			continue;
 		if (data->cmd_ops->trigger_type & tt)
-			data->ops->func(data, rec, event);
+			data->ops->func(data, NULL, NULL);
 	}
 }
 EXPORT_SYMBOL_GPL(event_triggers_post_call);
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 02/14] tracing: Add __find_event_file() to find event files without restrictions
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 01/14] tracing: Do not reference event data in post call triggers Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 03/14] tracing: Have event_trace_init() called by trace_init_tracefs() Steven Rostedt
                   ` (11 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0002-tracing-Add-__find_event_file-to-find-event-files-wi.patch --]
[-- Type: text/plain, Size: 2943 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

By adding the function __find_event_file() that can search for files without
restrictions, such as if the event associated with the file has a reg
function, or if it has the "ignore" flag set, the files that are associated
to ftrace internal events (like trace_marker and function events) can be
found and used.

find_event_file() still returns a "filtered" file, as most callers need a
valid trace event file. One created by the trace_events.h macros and not one
created for parsing ftrace specific events.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h        |  3 +++
 kernel/trace/trace_events.c | 22 +++++++++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 24b666891eaf..8ecca43d6aea 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1454,6 +1454,9 @@ extern void trace_event_enable_tgid_record(bool enable);
 extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
 extern int event_trace_del_tracer(struct trace_array *tr);
 
+extern struct trace_event_file *__find_event_file(struct trace_array *tr,
+						  const char *system,
+						  const char *event);
 extern struct trace_event_file *find_event_file(struct trace_array *tr,
 						const char *system,
 						const char *event);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 05c7172c6667..caf76355f0a3 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2473,8 +2473,9 @@ __trace_add_event_dirs(struct trace_array *tr)
 	}
 }
 
+/* Returns any file that matches the system and event */
 struct trace_event_file *
-find_event_file(struct trace_array *tr, const char *system,  const char *event)
+__find_event_file(struct trace_array *tr, const char *system, const char *event)
 {
 	struct trace_event_file *file;
 	struct trace_event_call *call;
@@ -2485,10 +2486,7 @@ find_event_file(struct trace_array *tr, const char *system,  const char *event)
 		call = file->event_call;
 		name = trace_event_name(call);
 
-		if (!name || !call->class || !call->class->reg)
-			continue;
-
-		if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+		if (!name || !call->class)
 			continue;
 
 		if (strcmp(event, name) == 0 &&
@@ -2498,6 +2496,20 @@ find_event_file(struct trace_array *tr, const char *system,  const char *event)
 	return NULL;
 }
 
+/* Returns valid trace event files that match system and event */
+struct trace_event_file *
+find_event_file(struct trace_array *tr, const char *system, const char *event)
+{
+	struct trace_event_file *file;
+
+	file = __find_event_file(tr, system, event);
+	if (!file || !file->event_call->class->reg ||
+	    file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+		return NULL;
+
+	return file;
+}
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 /* Avoid typos */
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 03/14] tracing: Have event_trace_init() called by trace_init_tracefs()
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 01/14] tracing: Do not reference event data in post call triggers Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 02/14] tracing: Add __find_event_file() to find event files without restrictions Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 04/14] tracing: Add brackets in ftrace event dynamic arrays Steven Rostedt
                   ` (10 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0003-tracing-Have-event_trace_init-called-by-trace_init_t.patch --]
[-- Type: text/plain, Size: 2231 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Instead of having both trace_init_tracefs() and event_trace_init() be called
by fs_initcall() routines, have event_trace_init() called directly by
trace_init_tracefs(). This will guarantee order of how the events are
created with respect to the rest of the ftrace infrastructure. This is
needed to be able to assoctiate event files with ftrace internal events,
such as the trace_marker.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c        | 2 ++
 kernel/trace/trace.h        | 1 +
 kernel/trace/trace_events.c | 4 +---
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 414d7210b2ec..e0d6ffb76985 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8111,6 +8111,8 @@ static __init int tracer_init_tracefs(void)
 	if (IS_ERR(d_tracer))
 		return 0;
 
+	event_trace_init();
+
 	init_tracer_tracefs(&global_trace, d_tracer);
 	ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8ecca43d6aea..2414fd72dedd 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1451,6 +1451,7 @@ trace_find_event_field(struct trace_event_call *call, char *name);
 extern void trace_event_enable_cmd_record(bool enable);
 extern void trace_event_enable_tgid_record(bool enable);
 
+extern int event_trace_init(void);
 extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
 extern int event_trace_del_tracer(struct trace_array *tr);
 
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index caf76355f0a3..5b647904a65b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -3144,7 +3144,7 @@ static __init int event_trace_enable_again(void)
 
 early_initcall(event_trace_enable_again);
 
-static __init int event_trace_init(void)
+__init int event_trace_init(void)
 {
 	struct trace_array *tr;
 	struct dentry *d_tracer;
@@ -3189,8 +3189,6 @@ void __init trace_event_init(void)
 	event_trace_enable();
 }
 
-fs_initcall(event_trace_init);
-
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 
 static DEFINE_SPINLOCK(test_spinlock);
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 04/14] tracing: Add brackets in ftrace event dynamic arrays
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (2 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 03/14] tracing: Have event_trace_init() called by trace_init_tracefs() Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 05/14] tracing: Do not show filter file for ftrace internal events Steven Rostedt
                   ` (9 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0004-tracing-Add-brackets-in-ftrace-event-dynamic-arrays.patch --]
[-- Type: text/plain, Size: 1121 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The dynamic arrays defined for ftrace internal events, such as the buf field
for trace_marker (ftrace/print) did not have brackets which makes the filter
code not accept it as a string. This is not currently an issues because the
filter code doesn't do anything for these events, but they will in the
future, and this needs to be fixed for when it does.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_export.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 548e62eb5c46..d842f1eadfe5 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -117,7 +117,7 @@ static void __always_unused ____ftrace_check_##name(void)		\
 
 #undef __dynamic_array
 #define __dynamic_array(type, item)					\
-	ret = trace_define_field(event_call, #type, #item,		\
+	ret = trace_define_field(event_call, #type "[]", #item,  \
 				 offsetof(typeof(field), item),		\
 				 0, is_signed_type(type), filter_type);\
 	if (ret)							\
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 05/14] tracing: Do not show filter file for ftrace internal events
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (3 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 04/14] tracing: Add brackets in ftrace event dynamic arrays Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-16  9:10   ` Namhyung Kim
  2018-05-14 20:58 ` [PATCH v2 06/14] tracing: Add trigger file for trace_markers tracefs/ftrace/print Steven Rostedt
                   ` (8 subsequent siblings)
  13 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0005-tracing-Do-not-show-filter-file-for-ftrace-internal-.patch --]
[-- Type: text/plain, Size: 1394 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The filter file in the ftrace internal events, like in
/sys/kernel/tracing/events/ftrace/function/filter is not attached to any
functionality. Do not create them as they are meaningless.

In the future, if an ftrace internal event gets filter functionality, then
it will need to create it directly.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 5b647904a65b..14ff4ff3caab 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2007,16 +2007,18 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
 			return -1;
 		}
 	}
-	trace_create_file("filter", 0644, file->dir, file,
-			  &ftrace_event_filter_fops);
 
 	/*
 	 * Only event directories that can be enabled should have
-	 * triggers.
+	 * triggers or filters.
 	 */
-	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
+	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
+		trace_create_file("filter", 0644, file->dir, file,
+				  &ftrace_event_filter_fops);
+
 		trace_create_file("trigger", 0644, file->dir, file,
 				  &event_trigger_fops);
+	}
 
 #ifdef CONFIG_HIST_TRIGGERS
 	trace_create_file("hist", 0444, file->dir, file,
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 06/14] tracing: Add trigger file for trace_markers tracefs/ftrace/print
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (4 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 05/14] tracing: Do not show filter file for ftrace internal events Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 07/14] tracing: Have zero size length in filter logic be full string Steven Rostedt
                   ` (7 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users,
	Joel Fernandes

[-- Attachment #1: 0006-tracing-Add-trigger-file-for-trace_markers-tracefs-f.patch --]
[-- Type: text/plain, Size: 4820 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Allow writing to the trace_markers file initiate triggers defined in
tracefs/ftrace/print/trigger file. This will allow of user space to trigger
the same type of triggers (including histograms) that the trace events use.

Had to create a ftrace_event_register() function that will become the
trace_marker print event's reg() function. This is required because of how
triggers are enabled:

  event_trigger_write() {
    event_trigger_regex_write() {
      trigger_process_regex() {
        for p in trigger_commands {
          p->func(); /* trigger_snapshot_cmd->func */
            event_trigger_callback() {
              cmd_ops->reg() /* register_trigger() */ {
                trace_event_trigger_enable_disable() {
                  trace_event_enable_disable() {
                    call->class->reg();

Without the reg() function, the trigger code will call a NULL pointer and
crash the system.

Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Karim Yaghmour <karim.yaghmour@opersys.com>
Cc: Brendan Gregg <bgregg@netflix.com>
Suggested-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c         | 17 +++++++++++++++++
 kernel/trace/trace.h         |  1 +
 kernel/trace/trace_entries.h |  6 ++++--
 kernel/trace/trace_export.c  |  7 +++++++
 4 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e0d6ffb76985..f11b89fa5049 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6074,6 +6074,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 {
 	struct trace_array *tr = filp->private_data;
 	struct ring_buffer_event *event;
+	enum event_trigger_type tt = ETT_NONE;
 	struct ring_buffer *buffer;
 	struct print_entry *entry;
 	unsigned long irq_flags;
@@ -6122,6 +6123,12 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 		written = cnt;
 	len = cnt;
 
+	if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
+		/* do not add \n before testing triggers, but add \0 */
+		entry->buf[cnt] = '\0';
+		tt = event_triggers_call(tr->trace_marker_file, entry, event);
+	}
+
 	if (entry->buf[cnt - 1] != '\n') {
 		entry->buf[cnt] = '\n';
 		entry->buf[cnt + 1] = '\0';
@@ -6130,6 +6137,9 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 
 	__buffer_unlock_commit(buffer, event);
 
+	if (tt)
+		event_triggers_post_call(tr->trace_marker_file, tt);
+
 	if (written > 0)
 		*fpos += written;
 
@@ -7896,6 +7906,7 @@ static __init void create_trace_instances(struct dentry *d_tracer)
 static void
 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 {
+	struct trace_event_file *file;
 	int cpu;
 
 	trace_create_file("available_tracers", 0444, d_tracer,
@@ -7928,6 +7939,12 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 	trace_create_file("trace_marker", 0220, d_tracer,
 			  tr, &tracing_mark_fops);
 
+	file = __find_event_file(tr, "ftrace", "print");
+	if (file && file->dir)
+		trace_create_file("trigger", 0644, file->dir, file,
+				  &event_trigger_fops);
+	tr->trace_marker_file = file;
+
 	trace_create_file("trace_marker_raw", 0220, d_tracer,
 			  tr, &tracing_mark_raw_fops);
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 2414fd72dedd..c7fa58d31a84 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -259,6 +259,7 @@ struct trace_array {
 	struct trace_options	*topts;
 	struct list_head	systems;
 	struct list_head	events;
+	struct trace_event_file *trace_marker_file;
 	cpumask_var_t		tracing_cpumask; /* only trace on set CPUs */
 	int			ref;
 #ifdef CONFIG_FUNCTION_TRACER
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index e3a658bac10f..1d67464ed95e 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -230,7 +230,7 @@ FTRACE_ENTRY(bprint, bprint_entry,
 	FILTER_OTHER
 );
 
-FTRACE_ENTRY(print, print_entry,
+FTRACE_ENTRY_REG(print, print_entry,
 
 	TRACE_PRINT,
 
@@ -242,7 +242,9 @@ FTRACE_ENTRY(print, print_entry,
 	F_printk("%ps: %s",
 		 (void *)__entry->ip, __entry->buf),
 
-	FILTER_OTHER
+	FILTER_OTHER,
+
+	ftrace_event_register
 );
 
 FTRACE_ENTRY(raw_data, raw_data_entry,
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index d842f1eadfe5..45630a76ed3a 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -14,6 +14,13 @@
 
 #include "trace_output.h"
 
+/* Stub function for events with triggers */
+static int ftrace_event_register(struct trace_event_call *call,
+				 enum trace_reg type, void *data)
+{
+	return 0;
+}
+
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM	ftrace
 
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 07/14] tracing: Have zero size length in filter logic be full string
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (5 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 06/14] tracing: Add trigger file for trace_markers tracefs/ftrace/print Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 08/14] tracing: Prevent further users of zero size static arrays in trace events Steven Rostedt
                   ` (6 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0007-tracing-Have-zero-size-length-in-filter-logic-be-ful.patch --]
[-- Type: text/plain, Size: 2007 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

As strings in trace events may not have a nul terminating character, the
filter string compares use the defined string length for the field for the
compares.

The trace_marker records data slightly different than do normal events. It's
size is zero, meaning that the string is the rest of the array, and that the
string also ends with '\0'.

If the size is zero, assume that the string is nul terminated and read the
string in question as is.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_filter.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 7d306b74230f..0171407d231f 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -750,31 +750,32 @@ static int filter_pred_none(struct filter_pred *pred, void *event)
  *
  * Note:
  * - @str might not be NULL-terminated if it's of type DYN_STRING
- *   or STATIC_STRING
+ *   or STATIC_STRING, unless @len is zero.
  */
 
 static int regex_match_full(char *str, struct regex *r, int len)
 {
-	if (strncmp(str, r->pattern, len) == 0)
-		return 1;
-	return 0;
+	/* len of zero means str is dynamic and ends with '\0' */
+	if (!len)
+		return strcmp(str, r->pattern) == 0;
+
+	return strncmp(str, r->pattern, len) == 0;
 }
 
 static int regex_match_front(char *str, struct regex *r, int len)
 {
-	if (len < r->len)
+	if (len && len < r->len)
 		return 0;
 
-	if (strncmp(str, r->pattern, r->len) == 0)
-		return 1;
-	return 0;
+	return strncmp(str, r->pattern, r->len) == 0;
 }
 
 static int regex_match_middle(char *str, struct regex *r, int len)
 {
-	if (strnstr(str, r->pattern, len))
-		return 1;
-	return 0;
+	if (!len)
+		return strstr(str, r->pattern) != NULL;
+
+	return strnstr(str, r->pattern, len) != NULL;
 }
 
 static int regex_match_end(char *str, struct regex *r, int len)
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 08/14] tracing: Prevent further users of zero size static arrays in trace events
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (6 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 07/14] tracing: Have zero size length in filter logic be full string Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 09/14] tracing: Allow histogram triggers to access ftrace internal events Steven Rostedt
                   ` (5 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0008-tracing-Prevent-further-users-of-zero-size-static-ar.patch --]
[-- Type: text/plain, Size: 1111 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

A zero size static array has special meaning in the ftrace infrastructure.
Trace events are for recording data in the trace buffers that is normally
difficult to obtain via probes or function tracing. There is no reason for
any trace event to declare a zero size static array.

If one does, BUILD_BUG_ON() will trigger and prevent the kernel from
compiling.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/trace/trace_events.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index bfda803b0a09..4ecdfe2e3580 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h
@@ -422,6 +422,7 @@ static struct trace_event_functions trace_event_type_funcs_##call = {	\
 	do {								\
 		char *type_str = #type"["__stringify(len)"]";		\
 		BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);			\
+		BUILD_BUG_ON(len <= 0);					\
 		ret = trace_define_field(event_call, type_str, #item,	\
 				 offsetof(typeof(field), item),		\
 				 sizeof(field.item),			\
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 09/14] tracing: Allow histogram triggers to access ftrace internal events
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (7 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 08/14] tracing: Prevent further users of zero size static arrays in trace events Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 10/14] tracing: Document trace_marker triggers Steven Rostedt
                   ` (4 subsequent siblings)
  13 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0009-tracing-Allow-histogram-triggers-to-access-ftrace-in.patch --]
[-- Type: text/plain, Size: 948 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Now that trace_marker can have triggers, including a histogram triggers, the
onmatch() and onmax() access the trace event. To do so, the search routine
to find the event file needs to use the raw __find_event_file() that does
not filter out ftrace events.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_hist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index b9061ed59bbd..046c716a6536 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2865,7 +2865,7 @@ static struct trace_event_file *event_file(struct trace_array *tr,
 {
 	struct trace_event_file *file;
 
-	file = find_event_file(tr, system, event_name);
+	file = __find_event_file(tr, system, event_name);
 	if (!file)
 		return ERR_PTR(-EINVAL);
 
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 10/14] tracing: Document trace_marker triggers
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (8 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 09/14] tracing: Allow histogram triggers to access ftrace internal events Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-14 21:47   ` Tom Zanussi
  2018-05-14 20:58 ` [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful Steven Rostedt
                   ` (3 subsequent siblings)
  13 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0010-tracing-Document-trace_marker-triggers.patch --]
[-- Type: text/plain, Size: 35563 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add documentation and an example on how to use trace_marker triggers.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Documentation/trace/events.rst    |   6 +-
 Documentation/trace/ftrace.rst    |   5 +
 Documentation/trace/histogram.txt | 546 +++++++++++++++++++++++++++++-
 3 files changed, 555 insertions(+), 2 deletions(-)

diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
index a5ea2cb0082b..1afae55dc55c 100644
--- a/Documentation/trace/events.rst
+++ b/Documentation/trace/events.rst
@@ -338,10 +338,14 @@ used for conditionally invoking triggers.
 
 The syntax for event triggers is roughly based on the syntax for
 set_ftrace_filter 'ftrace filter commands' (see the 'Filter commands'
-section of Documentation/trace/ftrace.txt), but there are major
+section of Documentation/trace/ftrace.rst), but there are major
 differences and the implementation isn't currently tied to it in any
 way, so beware about making generalizations between the two.
 
+Note: Writing into trace_marker (See Documentation/trace/ftrace.rst)
+     can also enable triggers that are written into
+     /sys/kernel/tracing/events/ftrace/print/trigger
+
 6.1 Expression syntax
 ---------------------
 
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 67d9c38e95eb..aad4776c0f5d 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -507,6 +507,11 @@ of ftrace. Here is a list of some of the key files:
 
 		trace_fd = open("trace_marker", WR_ONLY);
 
+	Note: Writing into the trace_marker file can also initiate triggers
+	      that are written into /sys/kernel/tracing/events/ftrace/print/trigger
+	      See "Event triggers" in Documentation/trace/events.rst and an
+              example in Documentation/trace/histogram.rst (Section 3.)
+
   trace_marker_raw:
 
 	This is similar to trace_marker above, but is meant for for binary data
diff --git a/Documentation/trace/histogram.txt b/Documentation/trace/histogram.txt
index 6e05510afc28..8c871f0c0e33 100644
--- a/Documentation/trace/histogram.txt
+++ b/Documentation/trace/histogram.txt
@@ -1604,7 +1604,6 @@
         Entries: 7
         Dropped: 0
 
-
 2.2 Inter-event hist triggers
 -----------------------------
 
@@ -1993,3 +1992,548 @@ hist trigger specification.
           Hits: 12970
           Entries: 2
           Dropped: 0
+
+3. User space creating a trigger
+--------------------------------
+
+Writing into /sys/kernel/tracing/trace_marker writes into the ftrace
+ring buffer. This can also act like an event, by writing into the trigger
+file located in /sys/kernel/tracing/events/ftrace/print/
+
+Modifying cyclictest to write into the trace_marker file before it sleeps
+and after it wakes up, something like this:
+
+static void traceputs(char *str)
+{
+	/* tracemark_fd is the trace_marker file descripto */
+	if (tracemark_fd < 0)
+		return;
+	/* write the tracemark message */
+	write(tracemark_fd, str, strlen(str));
+}
+
+And later add something like:
+
+	traceputs("start");
+	clock_nanosleep(...);
+	traceputs("end");
+
+We can make a histogram from this:
+
+ # cd /sys/kernel/tracing
+ # echo 'latency u64 lat' > synthetic_events
+ # echo 'hist:keys=common_pid:ts0=common_timestamp.usecs if buf == "start"' > events/ftrace/print/trigger
+ # echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"' >> events/ftrace/print/trigger
+ # echo 'hist:keys=lat,common_pid:sort=lat' > events/synthetic/latency/trigger
+
+The above created a synthetic event called "latency" and two histograms
+against the trace_marker, one gets triggered when "start" is written into the
+trace_marker file and the other when "end" is written. If the pids match, then
+it will call the "latency" synthetic event with the calculated latency as its
+parameter. Finally, a histogram is added to the latency synthetic event to
+record the calculated latency along with the pid.
+
+Now running cyclictest with:
+
+ # ./cyclictest -p80 -d0 -i250 -n -a -t --tracemark -b 1000
+
+ -p80  : run threads at priority 80
+ -d0   : have all threads run at the same interval
+ -i250 : start the interval at 250 microseconds (all threads will do this)
+ -n    : sleep with nanosleep
+ -a    : affine all threads to a separate CPU
+ -t    : one thread per available CPU
+ --tracemark : enable trace mark writing
+ -b 1000 : stop if any latency is greater than 1000 microseconds
+
+Note, the -b 1000 is used just to make --tracemark available.
+
+The we can see the histogram created by this with:
+
+ # cat events/synthetic/latency/hist
+# event histogram
+#
+# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
+#
+
+{ lat:        107, common_pid:       2039 } hitcount:          1
+{ lat:        122, common_pid:       2041 } hitcount:          1
+{ lat:        166, common_pid:       2039 } hitcount:          1
+{ lat:        174, common_pid:       2039 } hitcount:          1
+{ lat:        194, common_pid:       2041 } hitcount:          1
+{ lat:        196, common_pid:       2036 } hitcount:          1
+{ lat:        197, common_pid:       2038 } hitcount:          1
+{ lat:        198, common_pid:       2039 } hitcount:          1
+{ lat:        199, common_pid:       2039 } hitcount:          1
+{ lat:        200, common_pid:       2041 } hitcount:          1
+{ lat:        201, common_pid:       2039 } hitcount:          2
+{ lat:        202, common_pid:       2038 } hitcount:          1
+{ lat:        202, common_pid:       2043 } hitcount:          1
+{ lat:        203, common_pid:       2039 } hitcount:          1
+{ lat:        203, common_pid:       2036 } hitcount:          1
+{ lat:        203, common_pid:       2041 } hitcount:          1
+{ lat:        206, common_pid:       2038 } hitcount:          2
+{ lat:        207, common_pid:       2039 } hitcount:          1
+{ lat:        207, common_pid:       2036 } hitcount:          1
+{ lat:        208, common_pid:       2040 } hitcount:          1
+{ lat:        209, common_pid:       2043 } hitcount:          1
+{ lat:        210, common_pid:       2039 } hitcount:          1
+{ lat:        211, common_pid:       2039 } hitcount:          4
+{ lat:        212, common_pid:       2043 } hitcount:          1
+{ lat:        212, common_pid:       2039 } hitcount:          2
+{ lat:        213, common_pid:       2039 } hitcount:          1
+{ lat:        214, common_pid:       2038 } hitcount:          1
+{ lat:        214, common_pid:       2039 } hitcount:          2
+{ lat:        214, common_pid:       2042 } hitcount:          1
+{ lat:        215, common_pid:       2039 } hitcount:          1
+{ lat:        217, common_pid:       2036 } hitcount:          1
+{ lat:        217, common_pid:       2040 } hitcount:          1
+{ lat:        217, common_pid:       2039 } hitcount:          1
+{ lat:        218, common_pid:       2039 } hitcount:          6
+{ lat:        219, common_pid:       2039 } hitcount:          9
+{ lat:        220, common_pid:       2039 } hitcount:         11
+{ lat:        221, common_pid:       2039 } hitcount:          5
+{ lat:        221, common_pid:       2042 } hitcount:          1
+{ lat:        222, common_pid:       2039 } hitcount:          7
+{ lat:        223, common_pid:       2036 } hitcount:          1
+{ lat:        223, common_pid:       2039 } hitcount:          3
+{ lat:        224, common_pid:       2039 } hitcount:          4
+{ lat:        224, common_pid:       2037 } hitcount:          1
+{ lat:        224, common_pid:       2036 } hitcount:          2
+{ lat:        225, common_pid:       2039 } hitcount:          5
+{ lat:        225, common_pid:       2042 } hitcount:          1
+{ lat:        226, common_pid:       2039 } hitcount:          7
+{ lat:        226, common_pid:       2036 } hitcount:          4
+{ lat:        227, common_pid:       2039 } hitcount:          6
+{ lat:        227, common_pid:       2036 } hitcount:         12
+{ lat:        227, common_pid:       2043 } hitcount:          1
+{ lat:        228, common_pid:       2039 } hitcount:          7
+{ lat:        228, common_pid:       2036 } hitcount:         14
+{ lat:        229, common_pid:       2039 } hitcount:          9
+{ lat:        229, common_pid:       2036 } hitcount:          8
+{ lat:        229, common_pid:       2038 } hitcount:          1
+{ lat:        230, common_pid:       2039 } hitcount:         11
+{ lat:        230, common_pid:       2036 } hitcount:          6
+{ lat:        230, common_pid:       2043 } hitcount:          1
+{ lat:        230, common_pid:       2042 } hitcount:          2
+{ lat:        231, common_pid:       2041 } hitcount:          1
+{ lat:        231, common_pid:       2036 } hitcount:          6
+{ lat:        231, common_pid:       2043 } hitcount:          1
+{ lat:        231, common_pid:       2039 } hitcount:          8
+{ lat:        232, common_pid:       2037 } hitcount:          1
+{ lat:        232, common_pid:       2039 } hitcount:          6
+{ lat:        232, common_pid:       2040 } hitcount:          2
+{ lat:        232, common_pid:       2036 } hitcount:          5
+{ lat:        232, common_pid:       2043 } hitcount:          1
+{ lat:        233, common_pid:       2036 } hitcount:          5
+{ lat:        233, common_pid:       2039 } hitcount:         11
+{ lat:        234, common_pid:       2039 } hitcount:          4
+{ lat:        234, common_pid:       2038 } hitcount:          2
+{ lat:        234, common_pid:       2043 } hitcount:          2
+{ lat:        234, common_pid:       2036 } hitcount:         11
+{ lat:        234, common_pid:       2040 } hitcount:          1
+{ lat:        235, common_pid:       2037 } hitcount:          2
+{ lat:        235, common_pid:       2036 } hitcount:          8
+{ lat:        235, common_pid:       2043 } hitcount:          2
+{ lat:        235, common_pid:       2039 } hitcount:          5
+{ lat:        235, common_pid:       2042 } hitcount:          2
+{ lat:        235, common_pid:       2040 } hitcount:          4
+{ lat:        235, common_pid:       2041 } hitcount:          1
+{ lat:        236, common_pid:       2036 } hitcount:          7
+{ lat:        236, common_pid:       2037 } hitcount:          1
+{ lat:        236, common_pid:       2041 } hitcount:          5
+{ lat:        236, common_pid:       2039 } hitcount:          3
+{ lat:        236, common_pid:       2043 } hitcount:          9
+{ lat:        236, common_pid:       2040 } hitcount:          7
+{ lat:        237, common_pid:       2037 } hitcount:          1
+{ lat:        237, common_pid:       2040 } hitcount:          1
+{ lat:        237, common_pid:       2036 } hitcount:          9
+{ lat:        237, common_pid:       2039 } hitcount:          3
+{ lat:        237, common_pid:       2043 } hitcount:          8
+{ lat:        237, common_pid:       2042 } hitcount:          2
+{ lat:        237, common_pid:       2041 } hitcount:          2
+{ lat:        238, common_pid:       2043 } hitcount:         10
+{ lat:        238, common_pid:       2040 } hitcount:          1
+{ lat:        238, common_pid:       2037 } hitcount:          9
+{ lat:        238, common_pid:       2038 } hitcount:          1
+{ lat:        238, common_pid:       2039 } hitcount:          1
+{ lat:        238, common_pid:       2042 } hitcount:          3
+{ lat:        238, common_pid:       2036 } hitcount:          7
+{ lat:        239, common_pid:       2041 } hitcount:          1
+{ lat:        239, common_pid:       2043 } hitcount:         11
+{ lat:        239, common_pid:       2037 } hitcount:         11
+{ lat:        239, common_pid:       2038 } hitcount:          6
+{ lat:        239, common_pid:       2036 } hitcount:          7
+{ lat:        239, common_pid:       2040 } hitcount:          1
+{ lat:        239, common_pid:       2042 } hitcount:          9
+{ lat:        240, common_pid:       2037 } hitcount:         29
+{ lat:        240, common_pid:       2043 } hitcount:         15
+{ lat:        240, common_pid:       2040 } hitcount:         44
+{ lat:        240, common_pid:       2039 } hitcount:          1
+{ lat:        240, common_pid:       2041 } hitcount:          2
+{ lat:        240, common_pid:       2038 } hitcount:          1
+{ lat:        240, common_pid:       2036 } hitcount:         10
+{ lat:        240, common_pid:       2042 } hitcount:         13
+{ lat:        241, common_pid:       2036 } hitcount:         21
+{ lat:        241, common_pid:       2041 } hitcount:         36
+{ lat:        241, common_pid:       2037 } hitcount:         34
+{ lat:        241, common_pid:       2042 } hitcount:         14
+{ lat:        241, common_pid:       2040 } hitcount:         94
+{ lat:        241, common_pid:       2039 } hitcount:         12
+{ lat:        241, common_pid:       2038 } hitcount:          2
+{ lat:        241, common_pid:       2043 } hitcount:         28
+{ lat:        242, common_pid:       2040 } hitcount:        109
+{ lat:        242, common_pid:       2041 } hitcount:        506
+{ lat:        242, common_pid:       2039 } hitcount:        155
+{ lat:        242, common_pid:       2042 } hitcount:         21
+{ lat:        242, common_pid:       2037 } hitcount:         52
+{ lat:        242, common_pid:       2043 } hitcount:         21
+{ lat:        242, common_pid:       2036 } hitcount:         16
+{ lat:        242, common_pid:       2038 } hitcount:        156
+{ lat:        243, common_pid:       2037 } hitcount:         46
+{ lat:        243, common_pid:       2039 } hitcount:         40
+{ lat:        243, common_pid:       2042 } hitcount:        119
+{ lat:        243, common_pid:       2041 } hitcount:        611
+{ lat:        243, common_pid:       2036 } hitcount:         69
+{ lat:        243, common_pid:       2038 } hitcount:        784
+{ lat:        243, common_pid:       2040 } hitcount:        323
+{ lat:        243, common_pid:       2043 } hitcount:         14
+{ lat:        244, common_pid:       2043 } hitcount:         35
+{ lat:        244, common_pid:       2042 } hitcount:        305
+{ lat:        244, common_pid:       2039 } hitcount:          8
+{ lat:        244, common_pid:       2040 } hitcount:       4515
+{ lat:        244, common_pid:       2038 } hitcount:        371
+{ lat:        244, common_pid:       2037 } hitcount:         31
+{ lat:        244, common_pid:       2036 } hitcount:        114
+{ lat:        244, common_pid:       2041 } hitcount:       3396
+{ lat:        245, common_pid:       2036 } hitcount:        700
+{ lat:        245, common_pid:       2041 } hitcount:       2772
+{ lat:        245, common_pid:       2037 } hitcount:        268
+{ lat:        245, common_pid:       2039 } hitcount:        472
+{ lat:        245, common_pid:       2038 } hitcount:       2758
+{ lat:        245, common_pid:       2042 } hitcount:       3833
+{ lat:        245, common_pid:       2040 } hitcount:       3105
+{ lat:        245, common_pid:       2043 } hitcount:        645
+{ lat:        246, common_pid:       2038 } hitcount:       3451
+{ lat:        246, common_pid:       2041 } hitcount:        142
+{ lat:        246, common_pid:       2037 } hitcount:       5101
+{ lat:        246, common_pid:       2040 } hitcount:         68
+{ lat:        246, common_pid:       2043 } hitcount:       5099
+{ lat:        246, common_pid:       2039 } hitcount:       5608
+{ lat:        246, common_pid:       2042 } hitcount:       3723
+{ lat:        246, common_pid:       2036 } hitcount:       4738
+{ lat:        247, common_pid:       2042 } hitcount:        312
+{ lat:        247, common_pid:       2043 } hitcount:       2385
+{ lat:        247, common_pid:       2041 } hitcount:        452
+{ lat:        247, common_pid:       2038 } hitcount:        792
+{ lat:        247, common_pid:       2040 } hitcount:         78
+{ lat:        247, common_pid:       2036 } hitcount:       2375
+{ lat:        247, common_pid:       2039 } hitcount:       1834
+{ lat:        247, common_pid:       2037 } hitcount:       2655
+{ lat:        248, common_pid:       2037 } hitcount:         36
+{ lat:        248, common_pid:       2042 } hitcount:         11
+{ lat:        248, common_pid:       2038 } hitcount:        122
+{ lat:        248, common_pid:       2036 } hitcount:        135
+{ lat:        248, common_pid:       2039 } hitcount:         26
+{ lat:        248, common_pid:       2041 } hitcount:        503
+{ lat:        248, common_pid:       2043 } hitcount:         66
+{ lat:        248, common_pid:       2040 } hitcount:         46
+{ lat:        249, common_pid:       2037 } hitcount:         29
+{ lat:        249, common_pid:       2038 } hitcount:          1
+{ lat:        249, common_pid:       2043 } hitcount:         29
+{ lat:        249, common_pid:       2039 } hitcount:          8
+{ lat:        249, common_pid:       2042 } hitcount:         56
+{ lat:        249, common_pid:       2040 } hitcount:         27
+{ lat:        249, common_pid:       2041 } hitcount:         11
+{ lat:        249, common_pid:       2036 } hitcount:         27
+{ lat:        250, common_pid:       2038 } hitcount:          1
+{ lat:        250, common_pid:       2036 } hitcount:         30
+{ lat:        250, common_pid:       2040 } hitcount:         19
+{ lat:        250, common_pid:       2043 } hitcount:         22
+{ lat:        250, common_pid:       2042 } hitcount:         20
+{ lat:        250, common_pid:       2041 } hitcount:          1
+{ lat:        250, common_pid:       2039 } hitcount:          6
+{ lat:        250, common_pid:       2037 } hitcount:         48
+{ lat:        251, common_pid:       2037 } hitcount:         43
+{ lat:        251, common_pid:       2039 } hitcount:          1
+{ lat:        251, common_pid:       2036 } hitcount:         12
+{ lat:        251, common_pid:       2042 } hitcount:          2
+{ lat:        251, common_pid:       2041 } hitcount:          1
+{ lat:        251, common_pid:       2043 } hitcount:         15
+{ lat:        251, common_pid:       2040 } hitcount:          3
+{ lat:        252, common_pid:       2040 } hitcount:          1
+{ lat:        252, common_pid:       2036 } hitcount:         12
+{ lat:        252, common_pid:       2037 } hitcount:         21
+{ lat:        252, common_pid:       2043 } hitcount:         14
+{ lat:        253, common_pid:       2037 } hitcount:         21
+{ lat:        253, common_pid:       2039 } hitcount:          2
+{ lat:        253, common_pid:       2036 } hitcount:          9
+{ lat:        253, common_pid:       2043 } hitcount:          6
+{ lat:        253, common_pid:       2040 } hitcount:          1
+{ lat:        254, common_pid:       2036 } hitcount:          8
+{ lat:        254, common_pid:       2043 } hitcount:          3
+{ lat:        254, common_pid:       2041 } hitcount:          1
+{ lat:        254, common_pid:       2042 } hitcount:          1
+{ lat:        254, common_pid:       2039 } hitcount:          1
+{ lat:        254, common_pid:       2037 } hitcount:         12
+{ lat:        255, common_pid:       2043 } hitcount:          1
+{ lat:        255, common_pid:       2037 } hitcount:          2
+{ lat:        255, common_pid:       2036 } hitcount:          2
+{ lat:        255, common_pid:       2039 } hitcount:          8
+{ lat:        256, common_pid:       2043 } hitcount:          1
+{ lat:        256, common_pid:       2036 } hitcount:          4
+{ lat:        256, common_pid:       2039 } hitcount:          6
+{ lat:        257, common_pid:       2039 } hitcount:          5
+{ lat:        257, common_pid:       2036 } hitcount:          4
+{ lat:        258, common_pid:       2039 } hitcount:          5
+{ lat:        258, common_pid:       2036 } hitcount:          2
+{ lat:        259, common_pid:       2036 } hitcount:          7
+{ lat:        259, common_pid:       2039 } hitcount:          7
+{ lat:        260, common_pid:       2036 } hitcount:          8
+{ lat:        260, common_pid:       2039 } hitcount:          6
+{ lat:        261, common_pid:       2036 } hitcount:          5
+{ lat:        261, common_pid:       2039 } hitcount:          7
+{ lat:        262, common_pid:       2039 } hitcount:          5
+{ lat:        262, common_pid:       2036 } hitcount:          5
+{ lat:        263, common_pid:       2039 } hitcount:          7
+{ lat:        263, common_pid:       2036 } hitcount:          7
+{ lat:        264, common_pid:       2039 } hitcount:          9
+{ lat:        264, common_pid:       2036 } hitcount:          9
+{ lat:        265, common_pid:       2036 } hitcount:          5
+{ lat:        265, common_pid:       2039 } hitcount:          1
+{ lat:        266, common_pid:       2036 } hitcount:          1
+{ lat:        266, common_pid:       2039 } hitcount:          3
+{ lat:        267, common_pid:       2036 } hitcount:          1
+{ lat:        267, common_pid:       2039 } hitcount:          3
+{ lat:        268, common_pid:       2036 } hitcount:          1
+{ lat:        268, common_pid:       2039 } hitcount:          6
+{ lat:        269, common_pid:       2036 } hitcount:          1
+{ lat:        269, common_pid:       2043 } hitcount:          1
+{ lat:        269, common_pid:       2039 } hitcount:          2
+{ lat:        270, common_pid:       2040 } hitcount:          1
+{ lat:        270, common_pid:       2039 } hitcount:          6
+{ lat:        271, common_pid:       2041 } hitcount:          1
+{ lat:        271, common_pid:       2039 } hitcount:          5
+{ lat:        272, common_pid:       2039 } hitcount:         10
+{ lat:        273, common_pid:       2039 } hitcount:          8
+{ lat:        274, common_pid:       2039 } hitcount:          2
+{ lat:        275, common_pid:       2039 } hitcount:          1
+{ lat:        276, common_pid:       2039 } hitcount:          2
+{ lat:        276, common_pid:       2037 } hitcount:          1
+{ lat:        276, common_pid:       2038 } hitcount:          1
+{ lat:        277, common_pid:       2039 } hitcount:          1
+{ lat:        277, common_pid:       2042 } hitcount:          1
+{ lat:        278, common_pid:       2039 } hitcount:          1
+{ lat:        279, common_pid:       2039 } hitcount:          4
+{ lat:        279, common_pid:       2043 } hitcount:          1
+{ lat:        280, common_pid:       2039 } hitcount:          3
+{ lat:        283, common_pid:       2036 } hitcount:          2
+{ lat:        284, common_pid:       2039 } hitcount:          1
+{ lat:        284, common_pid:       2043 } hitcount:          1
+{ lat:        288, common_pid:       2039 } hitcount:          1
+{ lat:        289, common_pid:       2039 } hitcount:          1
+{ lat:        300, common_pid:       2039 } hitcount:          1
+{ lat:        384, common_pid:       2039 } hitcount:          1
+
+Totals:
+    Hits: 67625
+    Entries: 278
+    Dropped: 0
+
+Note, the writes are around the sleep, so ideally they will all be of 250
+microseconds. If you are wondering how there are several that are under
+250 microseconds, that is because the way cyclictest works, is if one
+iteration comes in late, the next one will set the timer to wake up less that
+250. That is, if an iteration came in 50 microseconds late, the next wake up
+will be at 200 microseconds.
+
+But this could easily be done in userspace. To make this even more
+interesting, we can mix the histogram between events that happened in the
+kernel with trace_marker.
+
+ # cd /sys/kernel/tracing
+ # echo 'latency u64 lat' > synthetic_events
+ # echo 'hist:keys=pid:ts0=common_timestamp.usecs' > events/sched/sched_waking/trigger
+ # echo '!hist:keys=common_pid:vals=hitcount:lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_switch).latency($lat) if buf == "end"' > events/ftrace/print/trigger
+ # echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).latency($lat) if buf == "end"' > events/ftrace/print/trigger
+ # echo 'hist:keys=lat,common_pid:sort=lat' > events/synthetic/latency/trigger
+
+The difference this time is that instead of using the trace_marker to start
+the latency, the sched_waking event is used, matching the common_pid for the
+trace_marker write with the pid that is being worken by sched_waking.
+
+After running cyclictest again with the same parameters, we now have:
+
+ # cat events/synthetic/latency/hist
+# event histogram
+#
+# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
+#
+
+{ lat:          7, common_pid:       2302 } hitcount:        640
+{ lat:          7, common_pid:       2299 } hitcount:         42
+{ lat:          7, common_pid:       2303 } hitcount:         18
+{ lat:          7, common_pid:       2305 } hitcount:        166
+{ lat:          7, common_pid:       2306 } hitcount:          1
+{ lat:          7, common_pid:       2301 } hitcount:         91
+{ lat:          7, common_pid:       2300 } hitcount:         17
+{ lat:          8, common_pid:       2303 } hitcount:       8296
+{ lat:          8, common_pid:       2304 } hitcount:       6864
+{ lat:          8, common_pid:       2305 } hitcount:       9464
+{ lat:          8, common_pid:       2301 } hitcount:       9213
+{ lat:          8, common_pid:       2306 } hitcount:       6246
+{ lat:          8, common_pid:       2302 } hitcount:       8797
+{ lat:          8, common_pid:       2299 } hitcount:       8771
+{ lat:          8, common_pid:       2300 } hitcount:       8119
+{ lat:          9, common_pid:       2305 } hitcount:       1519
+{ lat:          9, common_pid:       2299 } hitcount:       2346
+{ lat:          9, common_pid:       2303 } hitcount:       2841
+{ lat:          9, common_pid:       2301 } hitcount:       1846
+{ lat:          9, common_pid:       2304 } hitcount:       3861
+{ lat:          9, common_pid:       2302 } hitcount:       1210
+{ lat:          9, common_pid:       2300 } hitcount:       2762
+{ lat:          9, common_pid:       2306 } hitcount:       4247
+{ lat:         10, common_pid:       2299 } hitcount:         16
+{ lat:         10, common_pid:       2306 } hitcount:        333
+{ lat:         10, common_pid:       2303 } hitcount:         16
+{ lat:         10, common_pid:       2304 } hitcount:        168
+{ lat:         10, common_pid:       2302 } hitcount:        240
+{ lat:         10, common_pid:       2301 } hitcount:         28
+{ lat:         10, common_pid:       2300 } hitcount:         95
+{ lat:         10, common_pid:       2305 } hitcount:         18
+{ lat:         11, common_pid:       2303 } hitcount:          5
+{ lat:         11, common_pid:       2305 } hitcount:          8
+{ lat:         11, common_pid:       2306 } hitcount:        221
+{ lat:         11, common_pid:       2302 } hitcount:         76
+{ lat:         11, common_pid:       2304 } hitcount:         26
+{ lat:         11, common_pid:       2300 } hitcount:        125
+{ lat:         11, common_pid:       2299 } hitcount:          2
+{ lat:         12, common_pid:       2305 } hitcount:          3
+{ lat:         12, common_pid:       2300 } hitcount:          6
+{ lat:         12, common_pid:       2306 } hitcount:         90
+{ lat:         12, common_pid:       2302 } hitcount:          4
+{ lat:         12, common_pid:       2303 } hitcount:          1
+{ lat:         12, common_pid:       2304 } hitcount:        122
+{ lat:         13, common_pid:       2300 } hitcount:         12
+{ lat:         13, common_pid:       2301 } hitcount:          1
+{ lat:         13, common_pid:       2306 } hitcount:         32
+{ lat:         13, common_pid:       2302 } hitcount:          5
+{ lat:         13, common_pid:       2305 } hitcount:          1
+{ lat:         13, common_pid:       2303 } hitcount:          1
+{ lat:         13, common_pid:       2304 } hitcount:         61
+{ lat:         14, common_pid:       2303 } hitcount:          4
+{ lat:         14, common_pid:       2306 } hitcount:          5
+{ lat:         14, common_pid:       2305 } hitcount:          4
+{ lat:         14, common_pid:       2304 } hitcount:         62
+{ lat:         14, common_pid:       2302 } hitcount:         19
+{ lat:         14, common_pid:       2300 } hitcount:         33
+{ lat:         14, common_pid:       2299 } hitcount:          1
+{ lat:         14, common_pid:       2301 } hitcount:          4
+{ lat:         15, common_pid:       2305 } hitcount:          1
+{ lat:         15, common_pid:       2302 } hitcount:         25
+{ lat:         15, common_pid:       2300 } hitcount:         11
+{ lat:         15, common_pid:       2299 } hitcount:          5
+{ lat:         15, common_pid:       2301 } hitcount:          1
+{ lat:         15, common_pid:       2304 } hitcount:          8
+{ lat:         15, common_pid:       2303 } hitcount:          1
+{ lat:         15, common_pid:       2306 } hitcount:          6
+{ lat:         16, common_pid:       2302 } hitcount:         31
+{ lat:         16, common_pid:       2306 } hitcount:          3
+{ lat:         16, common_pid:       2300 } hitcount:          5
+{ lat:         17, common_pid:       2302 } hitcount:          6
+{ lat:         17, common_pid:       2303 } hitcount:          1
+{ lat:         18, common_pid:       2304 } hitcount:          1
+{ lat:         18, common_pid:       2302 } hitcount:          8
+{ lat:         18, common_pid:       2299 } hitcount:          1
+{ lat:         18, common_pid:       2301 } hitcount:          1
+{ lat:         19, common_pid:       2303 } hitcount:          4
+{ lat:         19, common_pid:       2304 } hitcount:          5
+{ lat:         19, common_pid:       2302 } hitcount:          4
+{ lat:         19, common_pid:       2299 } hitcount:          3
+{ lat:         19, common_pid:       2306 } hitcount:          1
+{ lat:         19, common_pid:       2300 } hitcount:          4
+{ lat:         19, common_pid:       2305 } hitcount:          5
+{ lat:         20, common_pid:       2299 } hitcount:          2
+{ lat:         20, common_pid:       2302 } hitcount:          3
+{ lat:         20, common_pid:       2305 } hitcount:          1
+{ lat:         20, common_pid:       2300 } hitcount:          2
+{ lat:         20, common_pid:       2301 } hitcount:          2
+{ lat:         20, common_pid:       2303 } hitcount:          3
+{ lat:         21, common_pid:       2305 } hitcount:          1
+{ lat:         21, common_pid:       2299 } hitcount:          5
+{ lat:         21, common_pid:       2303 } hitcount:          4
+{ lat:         21, common_pid:       2302 } hitcount:          7
+{ lat:         21, common_pid:       2300 } hitcount:          1
+{ lat:         21, common_pid:       2301 } hitcount:          5
+{ lat:         21, common_pid:       2304 } hitcount:          2
+{ lat:         22, common_pid:       2302 } hitcount:          5
+{ lat:         22, common_pid:       2303 } hitcount:          1
+{ lat:         22, common_pid:       2306 } hitcount:          3
+{ lat:         22, common_pid:       2301 } hitcount:          2
+{ lat:         22, common_pid:       2300 } hitcount:          1
+{ lat:         22, common_pid:       2299 } hitcount:          1
+{ lat:         22, common_pid:       2305 } hitcount:          1
+{ lat:         22, common_pid:       2304 } hitcount:          1
+{ lat:         23, common_pid:       2299 } hitcount:          1
+{ lat:         23, common_pid:       2306 } hitcount:          2
+{ lat:         23, common_pid:       2302 } hitcount:          6
+{ lat:         24, common_pid:       2302 } hitcount:          3
+{ lat:         24, common_pid:       2300 } hitcount:          1
+{ lat:         24, common_pid:       2306 } hitcount:          2
+{ lat:         24, common_pid:       2305 } hitcount:          1
+{ lat:         24, common_pid:       2299 } hitcount:          1
+{ lat:         25, common_pid:       2300 } hitcount:          1
+{ lat:         25, common_pid:       2302 } hitcount:          4
+{ lat:         26, common_pid:       2302 } hitcount:          2
+{ lat:         27, common_pid:       2305 } hitcount:          1
+{ lat:         27, common_pid:       2300 } hitcount:          1
+{ lat:         27, common_pid:       2302 } hitcount:          3
+{ lat:         28, common_pid:       2306 } hitcount:          1
+{ lat:         28, common_pid:       2302 } hitcount:          4
+{ lat:         29, common_pid:       2302 } hitcount:          1
+{ lat:         29, common_pid:       2300 } hitcount:          2
+{ lat:         29, common_pid:       2306 } hitcount:          1
+{ lat:         29, common_pid:       2304 } hitcount:          1
+{ lat:         30, common_pid:       2302 } hitcount:          4
+{ lat:         31, common_pid:       2302 } hitcount:          6
+{ lat:         32, common_pid:       2302 } hitcount:          1
+{ lat:         33, common_pid:       2299 } hitcount:          1
+{ lat:         33, common_pid:       2302 } hitcount:          3
+{ lat:         34, common_pid:       2302 } hitcount:          2
+{ lat:         35, common_pid:       2302 } hitcount:          1
+{ lat:         35, common_pid:       2304 } hitcount:          1
+{ lat:         36, common_pid:       2302 } hitcount:          4
+{ lat:         37, common_pid:       2302 } hitcount:          6
+{ lat:         38, common_pid:       2302 } hitcount:          2
+{ lat:         39, common_pid:       2302 } hitcount:          2
+{ lat:         39, common_pid:       2304 } hitcount:          1
+{ lat:         40, common_pid:       2304 } hitcount:          2
+{ lat:         40, common_pid:       2302 } hitcount:          5
+{ lat:         41, common_pid:       2304 } hitcount:          1
+{ lat:         41, common_pid:       2302 } hitcount:          8
+{ lat:         42, common_pid:       2302 } hitcount:          6
+{ lat:         42, common_pid:       2304 } hitcount:          1
+{ lat:         43, common_pid:       2302 } hitcount:          3
+{ lat:         43, common_pid:       2304 } hitcount:          4
+{ lat:         44, common_pid:       2302 } hitcount:          6
+{ lat:         45, common_pid:       2302 } hitcount:          5
+{ lat:         46, common_pid:       2302 } hitcount:          5
+{ lat:         47, common_pid:       2302 } hitcount:          7
+{ lat:         48, common_pid:       2301 } hitcount:          1
+{ lat:         48, common_pid:       2302 } hitcount:          9
+{ lat:         49, common_pid:       2302 } hitcount:          3
+{ lat:         50, common_pid:       2302 } hitcount:          1
+{ lat:         50, common_pid:       2301 } hitcount:          1
+{ lat:         51, common_pid:       2302 } hitcount:          2
+{ lat:         51, common_pid:       2301 } hitcount:          1
+{ lat:         61, common_pid:       2302 } hitcount:          1
+{ lat:        110, common_pid:       2302 } hitcount:          1
+
+Totals:
+    Hits: 89565
+    Entries: 158
+    Dropped: 0
+
+This doesn't tell us any information about how late cyclictest may have
+worken up, but it does show us a nice histogram of how long it took from
+the time that cyclictest was worken to the time it made it into user space.
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (9 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 10/14] tracing: Document trace_marker triggers Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-16 12:53   ` Masami Hiramatsu
  2018-05-14 20:58 ` [PATCH v2 12/14] ftrace/selftest: Fix reset_trigger() to handle triggers with filters Steven Rostedt
                   ` (2 subsequent siblings)
  13 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0011-ftrace-selftest-Have-the-reset_trigger-code-be-a-bit.patch --]
[-- Type: text/plain, Size: 1919 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The trigger code is picky in how it can be disabled as there may be
dependencies between different events and synthetic events. Change the order
on how triggers are reset.

 1) Reset triggers of all synthetic events first
 2) Remove triggers with actions attached to them
 3) Remove all other triggers

If this order isn't followed, then some triggers will not be reset, and an
error may happen because a trigger is busy.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../testing/selftests/ftrace/test.d/functions | 21 ++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
index 2a4f16fc9819..8393b1c06027 100644
--- a/tools/testing/selftests/ftrace/test.d/functions
+++ b/tools/testing/selftests/ftrace/test.d/functions
@@ -15,14 +15,29 @@ reset_tracer() { # reset the current tracer
     echo nop > current_tracer
 }
 
-reset_trigger() { # reset all current setting triggers
-    grep -v ^# events/*/*/trigger |
+reset_trigger_file() {
+    # remove action triggers first
+    grep -H ':on[^:]*(' $@ |
+    while read line; do
+        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
+	file=`echo $line | cut -f1 -d:`
+	echo "!$cmd" >> $file
+    done
+    grep -Hv ^# $@ |
     while read line; do
         cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
-	echo "!$cmd" > `echo $line | cut -f1 -d:`
+	file=`echo $line | cut -f1 -d:`
+	echo "!$cmd" > $file
     done
 }
 
+reset_trigger() { # reset all current setting triggers
+    if [ -d events/synthetic ]; then
+        reset_trigger_file events/synthetic/*/trigger
+    fi
+    reset_trigger_file events/*/*/trigger
+}
+
 reset_events_filter() { # reset all current setting filters
     grep -v ^none events/*/*/filter |
     while read line; do
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 12/14] ftrace/selftest: Fix reset_trigger() to handle triggers with filters
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (10 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-16 12:56   ` Masami Hiramatsu
  2018-05-14 20:58 ` [PATCH v2 13/14] tracing/selftest: Add selftests to test trace_marker histogram triggers Steven Rostedt
  2018-05-14 20:58 ` [PATCH v2 14/14] tracing/selftest: Add test to test hist trigger between kernel event and trace_marker Steven Rostedt
  13 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0012-ftrace-selftest-Fix-reset_trigger-to-handle-triggers.patch --]
[-- Type: text/plain, Size: 2501 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The reset_trigger() function breaks up the command by a space ' '. This is
useful to ignore the '[active]' word for triggers when removing them. But if
the trigger has a filter (ie. "if prio < 10") then the filter needs to be
attached to the line that is written into the trigger file to remove it. But
the truncation removes the filter and the triggers are not cleared properly.

Before, reset_trigger() did this:

 # echo 'hist:keys=common_pid if prev_prio < 10' > events/sched/sched_switch/trigger
 # echo 'hist:keys=common_pid if next_prio < 10' >> events/sched/sched_switch/trigger
 # cat events/sched/sched_switch/trigger
hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if prev_prio < 10 [active]
hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if next_prio < 10 [active]

 reset_trigger() {
   echo '!hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048' >> events/sched/sched_switch/trigger
 }

 # cat events/sched/sched_switch/trigger
hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if prev_prio < 10 [active]
hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if next_prio < 10 [active]

After, where it includes the filter:

 reset_trigger() {
   echo '!hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if prev_prio < 10' >> events/sched/sched_switch/trigger
 }

 # cat events/sched/sched_switch/trigger
hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if next_prio < 10 [active]

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 tools/testing/selftests/ftrace/test.d/functions | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
index 8393b1c06027..e4645d5e3126 100644
--- a/tools/testing/selftests/ftrace/test.d/functions
+++ b/tools/testing/selftests/ftrace/test.d/functions
@@ -19,13 +19,13 @@ reset_trigger_file() {
     # remove action triggers first
     grep -H ':on[^:]*(' $@ |
     while read line; do
-        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
+        cmd=`echo $line | cut -f2- -d: | cut -f1 -d"["`
 	file=`echo $line | cut -f1 -d:`
 	echo "!$cmd" >> $file
     done
     grep -Hv ^# $@ |
     while read line; do
-        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
+        cmd=`echo $line | cut -f2- -d: | cut -f1 -d"["`
 	file=`echo $line | cut -f1 -d:`
 	echo "!$cmd" > $file
     done
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 13/14] tracing/selftest: Add selftests to test trace_marker histogram triggers
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (11 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 12/14] ftrace/selftest: Fix reset_trigger() to handle triggers with filters Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-16 13:07   ` Masami Hiramatsu
  2018-05-14 20:58 ` [PATCH v2 14/14] tracing/selftest: Add test to test hist trigger between kernel event and trace_marker Steven Rostedt
  13 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0013-tracing-selftest-Add-selftests-to-test-trace_marker-.patch --]
[-- Type: text/plain, Size: 4109 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add a couple of tests that test the trace_marker histogram triggers.
One does a straight histogram test, the other will create a synthetic event
and test the latency between two different writes (using filters to
differentiate between them).

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../trigger/trigger-trace-marker-synthetic.tc | 66 +++++++++++++++++++
 .../test.d/trigger/trigger-trace-marker.tc    | 49 ++++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc

diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
new file mode 100644
index 000000000000..8e7a043da7fb
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
@@ -0,0 +1,66 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test histogram with synthetic event
+# flags:
+
+do_reset() {
+    reset_trigger
+    echo > set_event
+    echo > synthetic_events
+    clear_trace
+}
+
+fail() { #msg
+    do_reset
+    echo $1
+    exit_fail
+}
+
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f synthetic_events ]; then
+    echo "synthetic events not supported"
+    exit_unsupported
+fi
+
+if [ ! -d events/ftrace/print ]; then
+    echo "event trace_marker is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f events/ftrace/print/trigger ]; then
+    echo "event trigger is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f events/ftrace/print/hist ]; then
+    echo "hist trigger is not supported"
+    exit_unsupported
+fi
+
+do_reset
+
+echo "Test histogram trace_marker to trace_marker latency histogram trigger"
+
+echo 'latency u64 lat' > synthetic_events
+echo 'hist:keys=common_pid:ts0=common_timestamp.usecs if buf == "start"' > events/ftrace/print/trigger
+echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"' >> events/ftrace/print/trigger
+echo 'hist:keys=common_pid,lat:sort=lat' > events/synthetic/latency/trigger
+echo -n "start" > trace_marker
+echo -n "end" > trace_marker
+
+cnt=`grep 'hitcount: *1$' events/ftrace/print/hist | wc -l`
+
+if [ $cnt -ne 2 ]; then
+    fail "hist trace_marker trigger did not trigger correctly"
+fi
+
+grep 'hitcount: *1$' events/synthetic/latency/hist > /dev/null || \
+    fail "hist trigger did not trigger "
+
+do_reset
+
+exit 0
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc
new file mode 100644
index 000000000000..48e7ac1ccbc1
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc
@@ -0,0 +1,49 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test histogram trigger
+# flags: instance
+
+do_reset() {
+    reset_trigger
+    echo > set_event
+    clear_trace
+}
+
+fail() { #msg
+    do_reset
+    echo $1
+    exit_fail
+}
+
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -d events/ftrace/print ]; then
+    echo "event trace_marker is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f events/ftrace/print/trigger ]; then
+    echo "event trigger is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f events/ftrace/print/hist ]; then
+    echo "hist trigger is not supported"
+    exit_unsupported
+fi
+
+do_reset
+
+echo "Test histogram trace_marker tigger"
+
+echo 'hist:keys=common_pid' > events/ftrace/print/trigger
+for i in `seq 1 10` ; do echo "hello" > trace_marker; done
+grep 'hitcount: *10$' events/ftrace/print/hist > /dev/null || \
+    fail "hist trigger did not trigger correct times on trace_marker"
+
+do_reset
+
+exit 0
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* [PATCH v2 14/14] tracing/selftest: Add test to test hist trigger between kernel event and trace_marker
  2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
                   ` (12 preceding siblings ...)
  2018-05-14 20:58 ` [PATCH v2 13/14] tracing/selftest: Add selftests to test trace_marker histogram triggers Steven Rostedt
@ 2018-05-14 20:58 ` Steven Rostedt
  2018-05-16  9:11   ` Namhyung Kim
  13 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-14 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Tom Zanussi,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

[-- Attachment #1: 0014-tracing-selftest-Add-test-to-test-hist-trigger-betwe.patch --]
[-- Type: text/plain, Size: 1895 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add a test that tests a trigger that is initiated by a kernel event
(sched_waking) and compared to a write to the trace_marker.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../trigger/trigger-trace-marker-synthetic.tc | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
index 8e7a043da7fb..d8cfc36f228b 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
@@ -31,6 +31,11 @@ if [ ! -d events/ftrace/print ]; then
     exit_unsupported
 fi
 
+if [ ! -d events/sched/sched_waking ]; then
+    echo "event sched_waking is not supported"
+    exit_unsupported
+fi
+
 if [ ! -f events/ftrace/print/trigger ]; then
     echo "event trigger is not supported"
     exit_unsupported
@@ -63,4 +68,21 @@ grep 'hitcount: *1$' events/synthetic/latency/hist > /dev/null || \
 
 do_reset
 
+echo "Test histogram kernel event to trace_marker latency histogram trigger"
+
+echo 'latency u64 lat' > synthetic_events
+echo 'hist:keys=pid:ts0=common_timestamp.usecs' > events/sched/sched_waking/trigger
+echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat)' > events/ftrace/print/trigger
+echo 'hist:keys=common_pid,lat:sort=lat' > events/synthetic/latency/trigger
+sleep 1
+echo "hello" > trace_marker
+
+grep 'hitcount: *1$' events/ftrace/print/hist > /dev/null || \
+    fail "hist trigger did not trigger correct times on trace_marker"
+
+grep 'hitcount: *1$' events/synthetic/latency/hist > /dev/null || \
+    fail "hist trigger did not trigger "
+
+do_reset
+
 exit 0
-- 
2.17.0

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 10/14] tracing: Document trace_marker triggers
  2018-05-14 20:58 ` [PATCH v2 10/14] tracing: Document trace_marker triggers Steven Rostedt
@ 2018-05-14 21:47   ` Tom Zanussi
  2018-05-16 13:55     ` Steven Rostedt
  0 siblings, 1 reply; 30+ messages in thread
From: Tom Zanussi @ 2018-05-14 21:47 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

Hi Steve,

This is a nice new event feature - thanks for doing it!  Some minor typo
comments below..

On Mon, 2018-05-14 at 16:58 -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Add documentation and an example on how to use trace_marker triggers.
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  Documentation/trace/events.rst    |   6 +-
>  Documentation/trace/ftrace.rst    |   5 +
>  Documentation/trace/histogram.txt | 546 +++++++++++++++++++++++++++++-
>  3 files changed, 555 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst
> index a5ea2cb0082b..1afae55dc55c 100644
> --- a/Documentation/trace/events.rst
> +++ b/Documentation/trace/events.rst
> @@ -338,10 +338,14 @@ used for conditionally invoking triggers.
>  
>  The syntax for event triggers is roughly based on the syntax for
>  set_ftrace_filter 'ftrace filter commands' (see the 'Filter commands'
> -section of Documentation/trace/ftrace.txt), but there are major
> +section of Documentation/trace/ftrace.rst), but there are major
>  differences and the implementation isn't currently tied to it in any
>  way, so beware about making generalizations between the two.
>  
> +Note: Writing into trace_marker (See Documentation/trace/ftrace.rst)
> +     can also enable triggers that are written into
> +     /sys/kernel/tracing/events/ftrace/print/trigger
> +
>  6.1 Expression syntax
>  ---------------------
>  
> diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
> index 67d9c38e95eb..aad4776c0f5d 100644
> --- a/Documentation/trace/ftrace.rst
> +++ b/Documentation/trace/ftrace.rst
> @@ -507,6 +507,11 @@ of ftrace. Here is a list of some of the key files:
>  
>  		trace_fd = open("trace_marker", WR_ONLY);
>  
> +	Note: Writing into the trace_marker file can also initiate triggers
> +	      that are written into /sys/kernel/tracing/events/ftrace/print/trigger
> +	      See "Event triggers" in Documentation/trace/events.rst and an
> +              example in Documentation/trace/histogram.rst (Section 3.)
> +
>    trace_marker_raw:
>  
>  	This is similar to trace_marker above, but is meant for for binary data
> diff --git a/Documentation/trace/histogram.txt b/Documentation/trace/histogram.txt
> index 6e05510afc28..8c871f0c0e33 100644
> --- a/Documentation/trace/histogram.txt
> +++ b/Documentation/trace/histogram.txt
> @@ -1604,7 +1604,6 @@
>          Entries: 7
>          Dropped: 0
>  
> -
>  2.2 Inter-event hist triggers
>  -----------------------------
>  
> @@ -1993,3 +1992,548 @@ hist trigger specification.
>            Hits: 12970
>            Entries: 2
>            Dropped: 0
> +
> +3. User space creating a trigger
> +--------------------------------
> +
> +Writing into /sys/kernel/tracing/trace_marker writes into the ftrace
> +ring buffer. This can also act like an event, by writing into the trigger
> +file located in /sys/kernel/tracing/events/ftrace/print/
> +
> +Modifying cyclictest to write into the trace_marker file before it sleeps
> +and after it wakes up, something like this:
> +
> +static void traceputs(char *str)
> +{
> +	/* tracemark_fd is the trace_marker file descripto */
> 

Should be 'descriptor'?

> 
> +	if (tracemark_fd < 0)
> +		return;
> +	/* write the tracemark message */
> +	write(tracemark_fd, str, strlen(str));
> +}
> +
> +And later add something like:
> +
> +	traceputs("start");
> +	clock_nanosleep(...);
> +	traceputs("end");
> +
> +We can make a histogram from this:
> +
> + # cd /sys/kernel/tracing
> + # echo 'latency u64 lat' > synthetic_events
> + # echo 'hist:keys=common_pid:ts0=common_timestamp.usecs if buf == "start"' > events/ftrace/print/trigger
> + # echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"' >> events/ftrace/print/trigger
> + # echo 'hist:keys=lat,common_pid:sort=lat' > events/synthetic/latency/trigger
> +
> +The above created a synthetic event called "latency" and two histograms
> +against the trace_marker, one gets triggered when "start" is written into the
> +trace_marker file and the other when "end" is written. If the pids match, then
> +it will call the "latency" synthetic event with the calculated latency as its
> +parameter. Finally, a histogram is added to the latency synthetic event to
> +record the calculated latency along with the pid.
> +
> +Now running cyclictest with:
> +
> + # ./cyclictest -p80 -d0 -i250 -n -a -t --tracemark -b 1000
> +
> + -p80  : run threads at priority 80
> + -d0   : have all threads run at the same interval
> + -i250 : start the interval at 250 microseconds (all threads will do this)
> + -n    : sleep with nanosleep
> + -a    : affine all threads to a separate CPU
> + -t    : one thread per available CPU
> + --tracemark : enable trace mark writing
> + -b 1000 : stop if any latency is greater than 1000 microseconds
> +
> +Note, the -b 1000 is used just to make --tracemark available.
> +
> +The we can see the histogram created by this with:
> +

'Then we can..

> 
> + # cat events/synthetic/latency/hist
> +# event histogram
> +#
> +# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
> +#
> +
> +{ lat:        107, common_pid:       2039 } hitcount:          1
> 

snip

> 
> +{ lat:        289, common_pid:       2039 } hitcount:          1
> +{ lat:        300, common_pid:       2039 } hitcount:          1
> +{ lat:        384, common_pid:       2039 } hitcount:          1
> +
> +Totals:
> +    Hits: 67625
> +    Entries: 278
> +    Dropped: 0
> +
> +Note, the writes are around the sleep, so ideally they will all be of 250
> +microseconds. If you are wondering how there are several that are under
> +250 microseconds, that is because the way cyclictest works, is if one
> +iteration comes in late, the next one will set the timer to wake up less that
> +250. That is, if an iteration came in 50 microseconds late, the next wake up
> +will be at 200 microseconds.
> +
> +But this could easily be done in userspace. To make this even more
> +interesting, we can mix the histogram between events that happened in the
> +kernel with trace_marker.
> +
> + # cd /sys/kernel/tracing
> + # echo 'latency u64 lat' > synthetic_events
> + # echo 'hist:keys=pid:ts0=common_timestamp.usecs' > events/sched/sched_waking/trigger
> + # echo '!hist:keys=common_pid:vals=hitcount:lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_switch).latency($lat) if buf == "end"' > events/ftrace/print/trigger

This seems out of place here - disabling an onmatch(sched.sched_switch)
trigger that you haven't mentioned before.

> 
> 
> # echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).latency($lat) if buf == "end"' > events/ftrace/print/trigger
> + # echo 'hist:keys=lat,common_pid:sort=lat' > events/synthetic/latency/trigger
> +
> +The difference this time is that instead of using the trace_marker to start
> +the latency, the sched_waking event is used, matching the common_pid for the
> +trace_marker write with the pid that is being worken by sched_waking.
> 

s/worken/woken ?

> 
> +
> +After running cyclictest again with the same parameters, we now have:
> +
> + # cat events/synthetic/latency/hist
> +# event histogram
> +#
> +# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
> +#
> +
> +{ lat:          7, common_pid:       2302 } hitcount:        640
> 

snip

> 
> +{ lat:         61, common_pid:       2302 } hitcount:          1
> +{ lat:        110, common_pid:       2302 } hitcount:          1
> +
> +Totals:
> +    Hits: 89565
> +    Entries: 158
> +    Dropped: 0
> +
> +This doesn't tell us any information about how late cyclictest may have
> +worken up, but it does show us a nice histogram of how long it took from
> +the time that cyclictest was worken to the time it made it into user space.
> 

A couple more that don't seem to be 'worken' ;-)

Tom

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 05/14] tracing: Do not show filter file for ftrace internal events
  2018-05-14 20:58 ` [PATCH v2 05/14] tracing: Do not show filter file for ftrace internal events Steven Rostedt
@ 2018-05-16  9:10   ` Namhyung Kim
  2018-05-16 10:44     ` Steven Rostedt
  0 siblings, 1 reply; 30+ messages in thread
From: Namhyung Kim @ 2018-05-16  9:10 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Masami Hiramatsu, Yann Ylavic, linux-rt-users,
	kernel-team

On Mon, May 14, 2018 at 04:58:50PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> The filter file in the ftrace internal events, like in
> /sys/kernel/tracing/events/ftrace/function/filter is not attached to any
> functionality. Do not create them as they are meaningless.
> 
> In the future, if an ftrace internal event gets filter functionality, then
> it will need to create it directly.
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  kernel/trace/trace_events.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 5b647904a65b..14ff4ff3caab 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -2007,16 +2007,18 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
>  			return -1;
>  		}
>  	}
> -	trace_create_file("filter", 0644, file->dir, file,
> -			  &ftrace_event_filter_fops);
>  
>  	/*
>  	 * Only event directories that can be enabled should have
> -	 * triggers.
> +	 * triggers or filters.
>  	 */
> -	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
> +	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
> +		trace_create_file("filter", 0644, file->dir, file,
> +				  &ftrace_event_filter_fops);
> +
>  		trace_create_file("trigger", 0644, file->dir, file,
>  				  &event_trigger_fops);
> +	}
>  
>  #ifdef CONFIG_HIST_TRIGGERS
>  	trace_create_file("hist", 0444, file->dir, file,

What about moving the "hist" file as well since it's meaningless
without the trigger.

Thanks,
Namhyung

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 14/14] tracing/selftest: Add test to test hist trigger between kernel event and trace_marker
  2018-05-14 20:58 ` [PATCH v2 14/14] tracing/selftest: Add test to test hist trigger between kernel event and trace_marker Steven Rostedt
@ 2018-05-16  9:11   ` Namhyung Kim
  2018-05-16 14:09     ` Steven Rostedt
  0 siblings, 1 reply; 30+ messages in thread
From: Namhyung Kim @ 2018-05-16  9:11 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Masami Hiramatsu, Yann Ylavic, linux-rt-users,
	kernel-team

On Mon, May 14, 2018 at 04:58:59PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Add a test that tests a trigger that is initiated by a kernel event
> (sched_waking) and compared to a write to the trace_marker.
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  .../trigger/trigger-trace-marker-synthetic.tc | 22 +++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
> index 8e7a043da7fb..d8cfc36f228b 100644
> --- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
> +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
> @@ -31,6 +31,11 @@ if [ ! -d events/ftrace/print ]; then
>      exit_unsupported
>  fi
>  
> +if [ ! -d events/sched/sched_waking ]; then
> +    echo "event sched_waking is not supported"
> +    exit_unsupported
> +fi
> +
>  if [ ! -f events/ftrace/print/trigger ]; then
>      echo "event trigger is not supported"
>      exit_unsupported
> @@ -63,4 +68,21 @@ grep 'hitcount: *1$' events/synthetic/latency/hist > /dev/null || \
>  
>  do_reset
>  
> +echo "Test histogram kernel event to trace_marker latency histogram trigger"
> +
> +echo 'latency u64 lat' > synthetic_events
> +echo 'hist:keys=pid:ts0=common_timestamp.usecs' > events/sched/sched_waking/trigger
> +echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat)' > events/ftrace/print/trigger

Shouldn't it be "onmatch(sched.sched_waking)" ?

Thanks,
Namhyung


> +echo 'hist:keys=common_pid,lat:sort=lat' > events/synthetic/latency/trigger
> +sleep 1
> +echo "hello" > trace_marker
> +
> +grep 'hitcount: *1$' events/ftrace/print/hist > /dev/null || \
> +    fail "hist trigger did not trigger correct times on trace_marker"
> +
> +grep 'hitcount: *1$' events/synthetic/latency/hist > /dev/null || \
> +    fail "hist trigger did not trigger "
> +
> +do_reset
> +
>  exit 0
> -- 
> 2.17.0
> 
> 

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 05/14] tracing: Do not show filter file for ftrace internal events
  2018-05-16  9:10   ` Namhyung Kim
@ 2018-05-16 10:44     ` Steven Rostedt
  0 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-16 10:44 UTC (permalink / raw)
  To: Namhyung Kim
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Masami Hiramatsu, Yann Ylavic, linux-rt-users,
	kernel-team

On Wed, 16 May 2018 18:10:25 +0900
Namhyung Kim <namhyung@kernel.org> wrote:

  
> >  	/*
> >  	 * Only event directories that can be enabled should have
> > -	 * triggers.
> > +	 * triggers or filters.
> >  	 */
> > -	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
> > +	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
> > +		trace_create_file("filter", 0644, file->dir, file,
> > +				  &ftrace_event_filter_fops);
> > +
> >  		trace_create_file("trigger", 0644, file->dir, file,
> >  				  &event_trigger_fops);
> > +	}
> >  
> >  #ifdef CONFIG_HIST_TRIGGERS
> >  	trace_create_file("hist", 0444, file->dir, file,  
> 
> What about moving the "hist" file as well since it's meaningless
> without the trigger.

I thought about doing this too. But when I had to manually create the
trigger file, I'll have to also manually create the hist file. As the
hist file is read only and rather harmless, I figured I'd just leave it
as is. The filter file is a command file and this patch wants to remove
the confusion of writing into the file and having no effect.

-- Steve

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful
  2018-05-14 20:58 ` [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful Steven Rostedt
@ 2018-05-16 12:53   ` Masami Hiramatsu
  2018-05-16 14:00     ` Steven Rostedt
  0 siblings, 1 reply; 30+ messages in thread
From: Masami Hiramatsu @ 2018-05-16 12:53 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Masami Hiramatsu, Namhyung Kim, Yann Ylavic,
	linux-rt-users

On Mon, 14 May 2018 16:58:56 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> The trigger code is picky in how it can be disabled as there may be
> dependencies between different events and synthetic events. Change the order
> on how triggers are reset.
> 
>  1) Reset triggers of all synthetic events first
>  2) Remove triggers with actions attached to them
>  3) Remove all other triggers
> 
> If this order isn't followed, then some triggers will not be reset, and an
> error may happen because a trigger is busy.

Ah, right!

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

I think this should go into stable tree too.

Thank you!

> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  .../testing/selftests/ftrace/test.d/functions | 21 ++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> index 2a4f16fc9819..8393b1c06027 100644
> --- a/tools/testing/selftests/ftrace/test.d/functions
> +++ b/tools/testing/selftests/ftrace/test.d/functions
> @@ -15,14 +15,29 @@ reset_tracer() { # reset the current tracer
>      echo nop > current_tracer
>  }
>  
> -reset_trigger() { # reset all current setting triggers
> -    grep -v ^# events/*/*/trigger |
> +reset_trigger_file() {
> +    # remove action triggers first
> +    grep -H ':on[^:]*(' $@ |
> +    while read line; do
> +        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> +	file=`echo $line | cut -f1 -d:`
> +	echo "!$cmd" >> $file
> +    done
> +    grep -Hv ^# $@ |
>      while read line; do
>          cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> -	echo "!$cmd" > `echo $line | cut -f1 -d:`
> +	file=`echo $line | cut -f1 -d:`
> +	echo "!$cmd" > $file
>      done
>  }
>  
> +reset_trigger() { # reset all current setting triggers
> +    if [ -d events/synthetic ]; then
> +        reset_trigger_file events/synthetic/*/trigger
> +    fi
> +    reset_trigger_file events/*/*/trigger
> +}
> +
>  reset_events_filter() { # reset all current setting filters
>      grep -v ^none events/*/*/filter |
>      while read line; do
> -- 
> 2.17.0
> 
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 12/14] ftrace/selftest: Fix reset_trigger() to handle triggers with filters
  2018-05-14 20:58 ` [PATCH v2 12/14] ftrace/selftest: Fix reset_trigger() to handle triggers with filters Steven Rostedt
@ 2018-05-16 12:56   ` Masami Hiramatsu
  2018-05-16 14:04     ` Steven Rostedt
  0 siblings, 1 reply; 30+ messages in thread
From: Masami Hiramatsu @ 2018-05-16 12:56 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Masami Hiramatsu, Namhyung Kim, Yann Ylavic,
	linux-rt-users

On Mon, 14 May 2018 16:58:57 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> The reset_trigger() function breaks up the command by a space ' '. This is
> useful to ignore the '[active]' word for triggers when removing them. But if
> the trigger has a filter (ie. "if prio < 10") then the filter needs to be
> attached to the line that is written into the trigger file to remove it. But
> the truncation removes the filter and the triggers are not cleared properly.
> 
> Before, reset_trigger() did this:
> 
>  # echo 'hist:keys=common_pid if prev_prio < 10' > events/sched/sched_switch/trigger
>  # echo 'hist:keys=common_pid if next_prio < 10' >> events/sched/sched_switch/trigger
>  # cat events/sched/sched_switch/trigger
> hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if prev_prio < 10 [active]
> hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if next_prio < 10 [active]
> 
>  reset_trigger() {
>    echo '!hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048' >> events/sched/sched_switch/trigger
>  }
> 
>  # cat events/sched/sched_switch/trigger
> hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if prev_prio < 10 [active]
> hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if next_prio < 10 [active]
> 
> After, where it includes the filter:
> 
>  reset_trigger() {
>    echo '!hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if prev_prio < 10' >> events/sched/sched_switch/trigger
>  }
> 
>  # cat events/sched/sched_switch/trigger
> hist:keys=common_pid:vals=hitcount:sort=hitcount:size=2048 if next_prio < 10 [active]
> 

This also looks good to me and needs to go into stable.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you,


> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  tools/testing/selftests/ftrace/test.d/functions | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> index 8393b1c06027..e4645d5e3126 100644
> --- a/tools/testing/selftests/ftrace/test.d/functions
> +++ b/tools/testing/selftests/ftrace/test.d/functions
> @@ -19,13 +19,13 @@ reset_trigger_file() {
>      # remove action triggers first
>      grep -H ':on[^:]*(' $@ |
>      while read line; do
> -        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> +        cmd=`echo $line | cut -f2- -d: | cut -f1 -d"["`
>  	file=`echo $line | cut -f1 -d:`
>  	echo "!$cmd" >> $file
>      done
>      grep -Hv ^# $@ |
>      while read line; do
> -        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> +        cmd=`echo $line | cut -f2- -d: | cut -f1 -d"["`
>  	file=`echo $line | cut -f1 -d:`
>  	echo "!$cmd" > $file
>      done
> -- 
> 2.17.0
> 
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 13/14] tracing/selftest: Add selftests to test trace_marker histogram triggers
  2018-05-14 20:58 ` [PATCH v2 13/14] tracing/selftest: Add selftests to test trace_marker histogram triggers Steven Rostedt
@ 2018-05-16 13:07   ` Masami Hiramatsu
  2018-05-16 14:06     ` Steven Rostedt
  0 siblings, 1 reply; 30+ messages in thread
From: Masami Hiramatsu @ 2018-05-16 13:07 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Masami Hiramatsu, Namhyung Kim, Yann Ylavic,
	linux-rt-users

On Mon, 14 May 2018 16:58:58 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Add a couple of tests that test the trace_marker histogram triggers.
> One does a straight histogram test, the other will create a synthetic event
> and test the latency between two different writes (using filters to
> differentiate between them).
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  .../trigger/trigger-trace-marker-synthetic.tc | 66 +++++++++++++++++++
>  .../test.d/trigger/trigger-trace-marker.tc    | 49 ++++++++++++++
>  2 files changed, 115 insertions(+)
>  create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
>  create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
> new file mode 100644
> index 000000000000..8e7a043da7fb
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc

OK, since the synthetic event may need histogram support, so this testname is OK.


> @@ -0,0 +1,66 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: event trigger - test histogram with synthetic event
> +# flags:
> +
> +do_reset() {
> +    reset_trigger
> +    echo > set_event
> +    echo > synthetic_events
> +    clear_trace
> +}
> +
> +fail() { #msg
> +    do_reset
> +    echo $1
> +    exit_fail
> +}
> +
> +if [ ! -f set_event ]; then
> +    echo "event tracing is not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -f synthetic_events ]; then
> +    echo "synthetic events not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -d events/ftrace/print ]; then
> +    echo "event trace_marker is not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -f events/ftrace/print/trigger ]; then
> +    echo "event trigger is not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -f events/ftrace/print/hist ]; then
> +    echo "hist trigger is not supported"
> +    exit_unsupported
> +fi
> +
> +do_reset
> +
> +echo "Test histogram trace_marker to trace_marker latency histogram trigger"
> +
> +echo 'latency u64 lat' > synthetic_events
> +echo 'hist:keys=common_pid:ts0=common_timestamp.usecs if buf == "start"' > events/ftrace/print/trigger
> +echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"' >> events/ftrace/print/trigger
> +echo 'hist:keys=common_pid,lat:sort=lat' > events/synthetic/latency/trigger
> +echo -n "start" > trace_marker
> +echo -n "end" > trace_marker

Ah, this is a great example how we can use this combination :D

> +
> +cnt=`grep 'hitcount: *1$' events/ftrace/print/hist | wc -l`
> +
> +if [ $cnt -ne 2 ]; then
> +    fail "hist trace_marker trigger did not trigger correctly"
> +fi
> +
> +grep 'hitcount: *1$' events/synthetic/latency/hist > /dev/null || \
> +    fail "hist trigger did not trigger "
> +
> +do_reset
> +
> +exit 0
> diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc
> new file mode 100644
> index 000000000000..48e7ac1ccbc1
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc

But this test actually kicks histogram, maybe trigger-trace-marker-hist.tc will be better, since we may need to add a simpler testcase just for checking whether trace-marker works with some actions (e.g. enable/disable other events).

Thank you,

> @@ -0,0 +1,49 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: event trigger - test histogram trigger
> +# flags: instance
> +
> +do_reset() {
> +    reset_trigger
> +    echo > set_event
> +    clear_trace
> +}
> +
> +fail() { #msg
> +    do_reset
> +    echo $1
> +    exit_fail
> +}
> +
> +if [ ! -f set_event ]; then
> +    echo "event tracing is not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -d events/ftrace/print ]; then
> +    echo "event trace_marker is not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -f events/ftrace/print/trigger ]; then
> +    echo "event trigger is not supported"
> +    exit_unsupported
> +fi
> +
> +if [ ! -f events/ftrace/print/hist ]; then
> +    echo "hist trigger is not supported"
> +    exit_unsupported
> +fi
> +
> +do_reset
> +
> +echo "Test histogram trace_marker tigger"
> +
> +echo 'hist:keys=common_pid' > events/ftrace/print/trigger
> +for i in `seq 1 10` ; do echo "hello" > trace_marker; done
> +grep 'hitcount: *10$' events/ftrace/print/hist > /dev/null || \
> +    fail "hist trigger did not trigger correct times on trace_marker"
> +
> +do_reset
> +
> +exit 0
> -- 
> 2.17.0
> 
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 10/14] tracing: Document trace_marker triggers
  2018-05-14 21:47   ` Tom Zanussi
@ 2018-05-16 13:55     ` Steven Rostedt
  2018-05-16 15:22       ` Tom Zanussi
  0 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-16 13:55 UTC (permalink / raw)
  To: Tom Zanussi
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

On Mon, 14 May 2018 16:47:07 -0500
Tom Zanussi <tom.zanussi@linux.intel.com> wrote:

> Hi Steve,
> 
> This is a nice new event feature - thanks for doing it!  Some minor typo
> comments below..

Can I get an Acked-by from you?



> > +3. User space creating a trigger
> > +--------------------------------
> > +
> > +Writing into /sys/kernel/tracing/trace_marker writes into the ftrace
> > +ring buffer. This can also act like an event, by writing into the trigger
> > +file located in /sys/kernel/tracing/events/ftrace/print/
> > +
> > +Modifying cyclictest to write into the trace_marker file before it sleeps
> > +and after it wakes up, something like this:
> > +
> > +static void traceputs(char *str)
> > +{
> > +	/* tracemark_fd is the trace_marker file descripto */
> >   
> 
> Should be 'descriptor'?

Fixed.



> > + # ./cyclictest -p80 -d0 -i250 -n -a -t --tracemark -b 1000
> > +
> > + -p80  : run threads at priority 80
> > + -d0   : have all threads run at the same interval
> > + -i250 : start the interval at 250 microseconds (all threads will do this)
> > + -n    : sleep with nanosleep
> > + -a    : affine all threads to a separate CPU
> > + -t    : one thread per available CPU
> > + --tracemark : enable trace mark writing
> > + -b 1000 : stop if any latency is greater than 1000 microseconds
> > +
> > +Note, the -b 1000 is used just to make --tracemark available.
> > +
> > +The we can see the histogram created by this with:
> > +  
> 
> 'Then we can..

Fixed


> > +The difference this time is that instead of using the trace_marker to start
> > +the latency, the sched_waking event is used, matching the common_pid for the
> > +trace_marker write with the pid that is being worken by sched_waking.
> >   
> 
> s/worken/woken ?

Fixed. (It's kind of like Borken)

> 
> > 
> > +
> > +After running cyclictest again with the same parameters, we now have:
> > +
> > + # cat events/synthetic/latency/hist
> > +# event histogram
> > +#
> > +# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
> > +#
> > +
> > +{ lat:          7, common_pid:       2302 } hitcount:        640
> >   
> 
> snip
> 
> > 
> > +{ lat:         61, common_pid:       2302 } hitcount:          1
> > +{ lat:        110, common_pid:       2302 } hitcount:          1
> > +
> > +Totals:
> > +    Hits: 89565
> > +    Entries: 158
> > +    Dropped: 0
> > +
> > +This doesn't tell us any information about how late cyclictest may have
> > +worken up, but it does show us a nice histogram of how long it took from
> > +the time that cyclictest was worken to the time it made it into user space.
> >   
> 
> A couple more that don't seem to be 'worken' ;-)

I have an itchy 'r' finger.

Thanks for the review, I just updated this.

Oh, I guess I think I prefer a "Reviewed-by" tag instead of Ack (gives
a stronger meaning).

-- Steve

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful
  2018-05-16 12:53   ` Masami Hiramatsu
@ 2018-05-16 14:00     ` Steven Rostedt
  2018-05-16 23:15       ` Masami Hiramatsu
  0 siblings, 1 reply; 30+ messages in thread
From: Steven Rostedt @ 2018-05-16 14:00 UTC (permalink / raw)
  To: Masami Hiramatsu
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Namhyung Kim, Yann Ylavic, linux-rt-users

On Wed, 16 May 2018 21:53:50 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> On Mon, 14 May 2018 16:58:56 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> > 
> > The trigger code is picky in how it can be disabled as there may be
> > dependencies between different events and synthetic events. Change the order
> > on how triggers are reset.
> > 
> >  1) Reset triggers of all synthetic events first
> >  2) Remove triggers with actions attached to them
> >  3) Remove all other triggers
> > 
> > If this order isn't followed, then some triggers will not be reset, and an
> > error may happen because a trigger is busy.  
> 
> Ah, right!
> 
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thanks!

> 
> I think this should go into stable tree too.

I wonder if I should break this into two patches then.

One for the actions before attached, and one for synthetic events?

Hmm, maybe not. As it can handle not having synthetic events, it should
be OK to let the update go to a time when they were not there.

Thoughts?

-- Steve

> 
> Thank you!
> 
> > 
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > ---
> >  .../testing/selftests/ftrace/test.d/functions | 21 ++++++++++++++++---
> >  1 file changed, 18 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> > index 2a4f16fc9819..8393b1c06027 100644
> > --- a/tools/testing/selftests/ftrace/test.d/functions
> > +++ b/tools/testing/selftests/ftrace/test.d/functions
> > @@ -15,14 +15,29 @@ reset_tracer() { # reset the current tracer
> >      echo nop > current_tracer
> >  }
> >  
> > -reset_trigger() { # reset all current setting triggers
> > -    grep -v ^# events/*/*/trigger |
> > +reset_trigger_file() {
> > +    # remove action triggers first
> > +    grep -H ':on[^:]*(' $@ |
> > +    while read line; do
> > +        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> > +	file=`echo $line | cut -f1 -d:`
> > +	echo "!$cmd" >> $file
> > +    done
> > +    grep -Hv ^# $@ |
> >      while read line; do
> >          cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> > -	echo "!$cmd" > `echo $line | cut -f1 -d:`
> > +	file=`echo $line | cut -f1 -d:`
> > +	echo "!$cmd" > $file
> >      done
> >  }
> >  
> > +reset_trigger() { # reset all current setting triggers
> > +    if [ -d events/synthetic ]; then
> > +        reset_trigger_file events/synthetic/*/trigger
> > +    fi
> > +    reset_trigger_file events/*/*/trigger
> > +}
> > +
> >  reset_events_filter() { # reset all current setting filters
> >      grep -v ^none events/*/*/filter |
> >      while read line; do
> > -- 
> > 2.17.0
> > 
> >   
> 
> 

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 12/14] ftrace/selftest: Fix reset_trigger() to handle triggers with filters
  2018-05-16 12:56   ` Masami Hiramatsu
@ 2018-05-16 14:04     ` Steven Rostedt
  0 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-16 14:04 UTC (permalink / raw)
  To: Masami Hiramatsu
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Namhyung Kim, Yann Ylavic, linux-rt-users

On Wed, 16 May 2018 21:56:12 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:


> This also looks good to me and needs to go into stable.
> 
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thanks Masami!

-- Steve

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 13/14] tracing/selftest: Add selftests to test trace_marker histogram triggers
  2018-05-16 13:07   ` Masami Hiramatsu
@ 2018-05-16 14:06     ` Steven Rostedt
  0 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-16 14:06 UTC (permalink / raw)
  To: Masami Hiramatsu
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Namhyung Kim, Yann Ylavic, linux-rt-users

On Wed, 16 May 2018 22:07:16 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> > --- /dev/null
> > +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker.tc  
> 
> But this test actually kicks histogram, maybe
> trigger-trace-marker-hist.tc will be better, since we may need to add
> a simpler testcase just for checking whether trace-marker works with
> some actions (e.g. enable/disable other events).

OK, will update that file. Thanks for reviewing.

-- Steve

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 14/14] tracing/selftest: Add test to test hist trigger between kernel event and trace_marker
  2018-05-16  9:11   ` Namhyung Kim
@ 2018-05-16 14:09     ` Steven Rostedt
  0 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-16 14:09 UTC (permalink / raw)
  To: Namhyung Kim
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Masami Hiramatsu, Yann Ylavic, linux-rt-users,
	kernel-team

On Wed, 16 May 2018 18:11:53 +0900
Namhyung Kim <namhyung@kernel.org> wrote:

 
> > +echo "Test histogram kernel event to trace_marker latency histogram trigger"
> > +
> > +echo 'latency u64 lat' > synthetic_events
> > +echo 'hist:keys=pid:ts0=common_timestamp.usecs' > events/sched/sched_waking/trigger
> > +echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat)' > events/ftrace/print/trigger  
> 
> Shouldn't it be "onmatch(sched.sched_waking)" ?

Ug, yes! Cut-and-paste fail :-p

I tested this my hand and did it correctly, but instead of
cut-and-pasting the command line, I cut and pasted the other test and
updated it.

Thanks for reviewing Namhyung!

-- Steve

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 10/14] tracing: Document trace_marker triggers
  2018-05-16 13:55     ` Steven Rostedt
@ 2018-05-16 15:22       ` Tom Zanussi
  2018-05-16 15:26         ` Steven Rostedt
  0 siblings, 1 reply; 30+ messages in thread
From: Tom Zanussi @ 2018-05-16 15:22 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

Hi Steve,

On Wed, 2018-05-16 at 09:55 -0400, Steven Rostedt wrote:
> On Mon, 14 May 2018 16:47:07 -0500
> Tom Zanussi <tom.zanussi@linux.intel.com> wrote:
> 
> > Hi Steve,
> > 
> > This is a nice new event feature - thanks for doing it!  Some minor typo
> > comments below..
> 
> Can I get an Acked-by from you?
> 
> 
> 
> > > +3. User space creating a trigger
> > > +--------------------------------
> > > +
> > > +Writing into /sys/kernel/tracing/trace_marker writes into the ftrace
> > > +ring buffer. This can also act like an event, by writing into the trigger
> > > +file located in /sys/kernel/tracing/events/ftrace/print/
> > > +
> > > +Modifying cyclictest to write into the trace_marker file before it sleeps
> > > +and after it wakes up, something like this:
> > > +
> > > +static void traceputs(char *str)
> > > +{
> > > +	/* tracemark_fd is the trace_marker file descripto */
> > >   
> > 
> > Should be 'descriptor'?
> 
> Fixed.
> 
> 
> 
> > > + # ./cyclictest -p80 -d0 -i250 -n -a -t --tracemark -b 1000
> > > +
> > > + -p80  : run threads at priority 80
> > > + -d0   : have all threads run at the same interval
> > > + -i250 : start the interval at 250 microseconds (all threads will do this)
> > > + -n    : sleep with nanosleep
> > > + -a    : affine all threads to a separate CPU
> > > + -t    : one thread per available CPU
> > > + --tracemark : enable trace mark writing
> > > + -b 1000 : stop if any latency is greater than 1000 microseconds
> > > +
> > > +Note, the -b 1000 is used just to make --tracemark available.
> > > +
> > > +The we can see the histogram created by this with:
> > > +  
> > 
> > 'Then we can..
> 
> Fixed
> 
> 
> > > +The difference this time is that instead of using the trace_marker to start
> > > +the latency, the sched_waking event is used, matching the common_pid for the
> > > +trace_marker write with the pid that is being worken by sched_waking.
> > >   
> > 
> > s/worken/woken ?
> 
> Fixed. (It's kind of like Borken)

:-)

> 
> > 
> > > 
> > > +
> > > +After running cyclictest again with the same parameters, we now have:
> > > +
> > > + # cat events/synthetic/latency/hist
> > > +# event histogram
> > > +#
> > > +# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
> > > +#
> > > +
> > > +{ lat:          7, common_pid:       2302 } hitcount:        640
> > >   
> > 
> > snip
> > 
> > > 
> > > +{ lat:         61, common_pid:       2302 } hitcount:          1
> > > +{ lat:        110, common_pid:       2302 } hitcount:          1
> > > +
> > > +Totals:
> > > +    Hits: 89565
> > > +    Entries: 158
> > > +    Dropped: 0
> > > +
> > > +This doesn't tell us any information about how late cyclictest may have
> > > +worken up, but it does show us a nice histogram of how long it took from
> > > +the time that cyclictest was worken to the time it made it into user space.
> > >   
> > 
> > A couple more that don't seem to be 'worken' ;-)
> 
> I have an itchy 'r' finger.
> 
> Thanks for the review, I just updated this.
> 
> Oh, I guess I think I prefer a "Reviewed-by" tag instead of Ack (gives
> a stronger meaning).

Sure, but noticed in the new version you just posted, that this line is
still in there for your second example:

+ # echo '!hist:keys=common_pid:vals=hitcount:lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_switch).latency($lat) if buf == "end"' > events/ftrace/print/trigger

Did you intend that, or am I missing something?

Anyway, you have my

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>

Thanks,

Tom

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 10/14] tracing: Document trace_marker triggers
  2018-05-16 15:22       ` Tom Zanussi
@ 2018-05-16 15:26         ` Steven Rostedt
  0 siblings, 0 replies; 30+ messages in thread
From: Steven Rostedt @ 2018-05-16 15:26 UTC (permalink / raw)
  To: Tom Zanussi
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Clark Williams, Karim Yaghmour, Brendan Gregg, Joel Fernandes,
	Masami Hiramatsu, Namhyung Kim, Yann Ylavic, linux-rt-users

On Wed, 16 May 2018 10:22:27 -0500
Tom Zanussi <tom.zanussi@linux.intel.com> wrote:

> Sure, but noticed in the new version you just posted, that this line is
> still in there for your second example:
> 
> + # echo '!hist:keys=common_pid:vals=hitcount:lat=common_timestamp.usecs-$ts0:sort=hitcount:size=2048:clock=global:onmatch(sched.sched_switch).latency($lat) if buf == "end"' > events/ftrace/print/trigger
> 
> Did you intend that, or am I missing something?

No, I am. From my reply, you can see I skipped it. I totally missed
that comment. I'll update that too.


> 
> Anyway, you have my
> 
> Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>

Thanks!

-- Steve

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful
  2018-05-16 14:00     ` Steven Rostedt
@ 2018-05-16 23:15       ` Masami Hiramatsu
  0 siblings, 0 replies; 30+ messages in thread
From: Masami Hiramatsu @ 2018-05-16 23:15 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: linux-kernel, Ingo Molnar, Andrew Morton, Thomas Gleixner,
	Tom Zanussi, Clark Williams, Karim Yaghmour, Brendan Gregg,
	Joel Fernandes, Namhyung Kim, Yann Ylavic, linux-rt-users

On Wed, 16 May 2018 10:00:04 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed, 16 May 2018 21:53:50 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > On Mon, 14 May 2018 16:58:56 -0400
> > Steven Rostedt <rostedt@goodmis.org> wrote:
> > 
> > > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> > > 
> > > The trigger code is picky in how it can be disabled as there may be
> > > dependencies between different events and synthetic events. Change the order
> > > on how triggers are reset.
> > > 
> > >  1) Reset triggers of all synthetic events first
> > >  2) Remove triggers with actions attached to them
> > >  3) Remove all other triggers
> > > 
> > > If this order isn't followed, then some triggers will not be reset, and an
> > > error may happen because a trigger is busy.  
> > 
> > Ah, right!
> > 
> > Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
> 
> Thanks!
> 
> > 
> > I think this should go into stable tree too.
> 
> I wonder if I should break this into two patches then.
> 
> One for the actions before attached, and one for synthetic events?
> 
> Hmm, maybe not. As it can handle not having synthetic events, it should
> be OK to let the update go to a time when they were not there.
> 
> Thoughts?

I think the latest test-set can be run on the any stable kernel,
and this correctly checks existence of the knob, so you don't need
to split it.

Thank you, 

> 
> -- Steve
> 
> > 
> > Thank you!
> > 
> > > 
> > > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > > ---
> > >  .../testing/selftests/ftrace/test.d/functions | 21 ++++++++++++++++---
> > >  1 file changed, 18 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> > > index 2a4f16fc9819..8393b1c06027 100644
> > > --- a/tools/testing/selftests/ftrace/test.d/functions
> > > +++ b/tools/testing/selftests/ftrace/test.d/functions
> > > @@ -15,14 +15,29 @@ reset_tracer() { # reset the current tracer
> > >      echo nop > current_tracer
> > >  }
> > >  
> > > -reset_trigger() { # reset all current setting triggers
> > > -    grep -v ^# events/*/*/trigger |
> > > +reset_trigger_file() {
> > > +    # remove action triggers first
> > > +    grep -H ':on[^:]*(' $@ |
> > > +    while read line; do
> > > +        cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> > > +	file=`echo $line | cut -f1 -d:`
> > > +	echo "!$cmd" >> $file
> > > +    done
> > > +    grep -Hv ^# $@ |
> > >      while read line; do
> > >          cmd=`echo $line | cut -f2- -d: | cut -f1 -d" "`
> > > -	echo "!$cmd" > `echo $line | cut -f1 -d:`
> > > +	file=`echo $line | cut -f1 -d:`
> > > +	echo "!$cmd" > $file
> > >      done
> > >  }
> > >  
> > > +reset_trigger() { # reset all current setting triggers
> > > +    if [ -d events/synthetic ]; then
> > > +        reset_trigger_file events/synthetic/*/trigger
> > > +    fi
> > > +    reset_trigger_file events/*/*/trigger
> > > +}
> > > +
> > >  reset_events_filter() { # reset all current setting filters
> > >      grep -v ^none events/*/*/filter |
> > >      while read line; do
> > > -- 
> > > 2.17.0
> > > 
> > >   
> > 
> > 
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 30+ messages in thread

end of thread, other threads:[~2018-05-16 23:15 UTC | newest]

Thread overview: 30+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-05-14 20:58 [PATCH v2 00/14] tracing: Add triggers to trace_marker writes Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 01/14] tracing: Do not reference event data in post call triggers Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 02/14] tracing: Add __find_event_file() to find event files without restrictions Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 03/14] tracing: Have event_trace_init() called by trace_init_tracefs() Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 04/14] tracing: Add brackets in ftrace event dynamic arrays Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 05/14] tracing: Do not show filter file for ftrace internal events Steven Rostedt
2018-05-16  9:10   ` Namhyung Kim
2018-05-16 10:44     ` Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 06/14] tracing: Add trigger file for trace_markers tracefs/ftrace/print Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 07/14] tracing: Have zero size length in filter logic be full string Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 08/14] tracing: Prevent further users of zero size static arrays in trace events Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 09/14] tracing: Allow histogram triggers to access ftrace internal events Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 10/14] tracing: Document trace_marker triggers Steven Rostedt
2018-05-14 21:47   ` Tom Zanussi
2018-05-16 13:55     ` Steven Rostedt
2018-05-16 15:22       ` Tom Zanussi
2018-05-16 15:26         ` Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 11/14] ftrace/selftest: Have the reset_trigger code be a bit more careful Steven Rostedt
2018-05-16 12:53   ` Masami Hiramatsu
2018-05-16 14:00     ` Steven Rostedt
2018-05-16 23:15       ` Masami Hiramatsu
2018-05-14 20:58 ` [PATCH v2 12/14] ftrace/selftest: Fix reset_trigger() to handle triggers with filters Steven Rostedt
2018-05-16 12:56   ` Masami Hiramatsu
2018-05-16 14:04     ` Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 13/14] tracing/selftest: Add selftests to test trace_marker histogram triggers Steven Rostedt
2018-05-16 13:07   ` Masami Hiramatsu
2018-05-16 14:06     ` Steven Rostedt
2018-05-14 20:58 ` [PATCH v2 14/14] tracing/selftest: Add test to test hist trigger between kernel event and trace_marker Steven Rostedt
2018-05-16  9:11   ` Namhyung Kim
2018-05-16 14:09     ` Steven Rostedt

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).