[PATCH v8 0/2] Add array printing support to libtraceevent

[PATCH v8 0/2] Add array printing support to libtraceevent

[Javi Merino]

This series add support to libtraceevent for dynamic arrays in traces.
The kernel learned to create this traces in 6ea22486ba46 ("tracing: Add
array printing helper"), which was merged for v4.0-rc1.

Changes since v6[0]:
  - Call the fields of the struct print_arg_int_array "field", "count"
    and "el_size" to match the definition of __print_array as Namhyung
    Kim suggests.  Incorporate his Acked-bys.

[0] http://thread.gmane.org/gmane.linux.kernel/1897935

Javi Merino (2):
  tools lib traceevent: factor out allocating and processing args
  tools lib traceevent: Add support for __print_array()

 tools/lib/traceevent/event-parse.c | 158 +++++++++++++++++++++++++++++--------
 tools/lib/traceevent/event-parse.h |   8 ++
 2 files changed, 135 insertions(+), 31 deletions(-)

-- 
1.9.1

[PATCH v8 1/2] tools lib traceevent: factor out allocating and processing args

[Javi Merino]

The sequence of allocating the print_arg field, calling process_arg()
and verifying that the next event delimiter is repeated twice in
process_hex() and will also be used for process_int_array().  Factor it
out to a function to avoid writing the same code again and again.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Javi Merino <javi.merino@arm.com>
---
 tools/lib/traceevent/event-parse.c | 77 ++++++++++++++++++++------------------
 1 file changed, 40 insertions(+), 37 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index afe20ed9fac8..ac20601257de 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -2014,6 +2014,38 @@ process_entry(struct event_format *event __maybe_unused, struct print_arg *arg,
 	return EVENT_ERROR;
 }
 
+static int alloc_and_process_delim(struct event_format *event, char *next_token,
+				   struct print_arg **print_arg)
+{
+	struct print_arg *field;
+	enum event_type type;
+	char *token;
+	int ret = 0;
+
+	field = alloc_arg();
+	if (!field) {
+		do_warning_event(event, "%s: not enough memory!", __func__);
+		errno = ENOMEM;
+		return -1;
+	}
+
+	type = process_arg(event, field, &token);
+
+	if (test_type_token(type, token, EVENT_DELIM, next_token)) {
+		errno = EINVAL;
+		ret = -1;
+		free_arg(field);
+		goto out_free_token;
+	}
+
+	*print_arg = field;
+
+out_free_token:
+	free_token(token);
+
+	return ret;
+}
+
 static char *arg_eval (struct print_arg *arg);
 
 static unsigned long long
@@ -2486,49 +2518,20 @@ out_free:
 static enum event_type
 process_hex(struct event_format *event, struct print_arg *arg, char **tok)
 {
-	struct print_arg *field;
-	enum event_type type;
-	char *token = NULL;
-
 	memset(arg, 0, sizeof(*arg));
 	arg->type = PRINT_HEX;
 
-	field = alloc_arg();
-	if (!field) {
-		do_warning_event(event, "%s: not enough memory!", __func__);
-		goto out_free;
-	}
-
-	type = process_arg(event, field, &token);
-
-	if (test_type_token(type, token, EVENT_DELIM, ","))
-		goto out_free;
-
-	arg->hex.field = field;
-
-	free_token(token);
-
-	field = alloc_arg();
-	if (!field) {
-		do_warning_event(event, "%s: not enough memory!", __func__);
-		*tok = NULL;
-		return EVENT_ERROR;
-	}
-
-	type = process_arg(event, field, &token);
-
-	if (test_type_token(type, token, EVENT_DELIM, ")"))
-		goto out_free;
+	if (alloc_and_process_delim(event, ",", &arg->hex.field))
+		goto out;
 
-	arg->hex.size = field;
+	if (alloc_and_process_delim(event, ")", &arg->hex.size))
+		goto free_field;
 
-	free_token(token);
-	type = read_token_item(tok);
-	return type;
+	return read_token_item(tok);
 
- out_free:
-	free_arg(field);
-	free_token(token);
+free_field:
+	free_arg(arg->hex.field);
+out:
 	*tok = NULL;
 	return EVENT_ERROR;
 }
-- 
1.9.1

[PATCH v8 2/2] tools lib traceevent: Add support for __print_array()

[Javi Merino]

Since 6ea22486ba46 ("tracing: Add array printing helper") trace can
traces with variable element size arrays.  Add support to parse them.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Javi Merino <javi.merino@arm.com>
---
 tools/lib/traceevent/event-parse.c | 93 ++++++++++++++++++++++++++++++++++++++
 tools/lib/traceevent/event-parse.h |  8 ++++
 2 files changed, 101 insertions(+)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index ac20601257de..838405ece41d 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -758,6 +758,11 @@ static void free_arg(struct print_arg *arg)
 		free_arg(arg->hex.field);
 		free_arg(arg->hex.size);
 		break;
+	case PRINT_INT_ARRAY:
+		free_arg(arg->int_array.field);
+		free_arg(arg->int_array.count);
+		free_arg(arg->int_array.el_size);
+		break;
 	case PRINT_TYPE:
 		free(arg->typecast.type);
 		free_arg(arg->typecast.item);
@@ -2537,6 +2542,32 @@ out:
 }
 
 static enum event_type
+process_int_array(struct event_format *event, struct print_arg *arg, char **tok)
+{
+	memset(arg, 0, sizeof(*arg));
+	arg->type = PRINT_INT_ARRAY;
+
+	if (alloc_and_process_delim(event, ",", &arg->int_array.field))
+		goto out;
+
+	if (alloc_and_process_delim(event, ",", &arg->int_array.count))
+		goto free_field;
+
+	if (alloc_and_process_delim(event, ")", &arg->int_array.el_size))
+		goto free_size;
+
+	return read_token_item(tok);
+
+free_size:
+	free_arg(arg->int_array.count);
+free_field:
+	free_arg(arg->int_array.field);
+out:
+	*tok = NULL;
+	return EVENT_ERROR;
+}
+
+static enum event_type
 process_dynamic_array(struct event_format *event, struct print_arg *arg, char **tok)
 {
 	struct format_field *field;
@@ -2831,6 +2862,10 @@ process_function(struct event_format *event, struct print_arg *arg,
 		free_token(token);
 		return process_hex(event, arg, tok);
 	}
+	if (strcmp(token, "__print_array") == 0) {
+		free_token(token);
+		return process_int_array(event, arg, tok);
+	}
 	if (strcmp(token, "__get_str") == 0) {
 		free_token(token);
 		return process_str(event, arg, tok);
@@ -3359,6 +3394,7 @@ eval_num_arg(void *data, int size, struct event_format *event, struct print_arg
 		break;
 	case PRINT_FLAGS:
 	case PRINT_SYMBOL:
+	case PRINT_INT_ARRAY:
 	case PRINT_HEX:
 		break;
 	case PRINT_TYPE:
@@ -3769,6 +3805,54 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 		}
 		break;
 
+	case PRINT_INT_ARRAY: {
+		void *num;
+		int el_size;
+
+		if (arg->int_array.field->type == PRINT_DYNAMIC_ARRAY) {
+			unsigned long offset;
+			struct format_field *field =
+				arg->int_array.field->dynarray.field;
+			offset = pevent_read_number(pevent,
+						    data + field->offset,
+						    field->size);
+			num = data + (offset & 0xffff);
+		} else {
+			field = arg->int_array.field->field.field;
+			if (!field) {
+				str = arg->int_array.field->field.name;
+				field = pevent_find_any_field(event, str);
+				if (!field)
+					goto out_warning_field;
+				arg->int_array.field->field.field = field;
+			}
+			num = data + field->offset;
+		}
+		len = eval_num_arg(data, size, event, arg->int_array.count);
+		el_size = eval_num_arg(data, size, event,
+				       arg->int_array.el_size);
+		for (i = 0; i < len; i++) {
+			if (i)
+				trace_seq_putc(s, ' ');
+
+			if (el_size == 1) {
+				trace_seq_printf(s, "%u", *(uint8_t *)num);
+			} else if (el_size == 2) {
+				trace_seq_printf(s, "%u", *(uint16_t *)num);
+			} else if (el_size == 4) {
+				trace_seq_printf(s, "%u", *(uint32_t *)num);
+			} else if (el_size == 8) {
+				trace_seq_printf(s, "%llu", *(uint64_t *)num);
+			} else {
+				trace_seq_printf(s, "BAD SIZE:%d 0x%x",
+						 el_size, *(uint8_t *)num);
+				el_size = 1;
+			}
+
+			num += el_size;
+		}
+		break;
+	}
 	case PRINT_TYPE:
 		break;
 	case PRINT_STRING: {
@@ -5259,6 +5343,15 @@ static void print_args(struct print_arg *args)
 		print_args(args->hex.size);
 		printf(")");
 		break;
+	case PRINT_INT_ARRAY:
+		printf("__print_array(");
+		print_args(args->int_array.field);
+		printf(", ");
+		print_args(args->int_array.count);
+		printf(", ");
+		print_args(args->int_array.el_size);
+		printf(")");
+		break;
 	case PRINT_STRING:
 	case PRINT_BSTRING:
 		printf("__get_str(%s)", args->string.string);
diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index 7a3873ff9a4f..94c514a0f045 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -245,6 +245,12 @@ struct print_arg_hex {
 	struct print_arg	*size;
 };
 
+struct print_arg_int_array {
+	struct print_arg	*field;
+	struct print_arg	*count;
+	struct print_arg	*el_size;
+};
+
 struct print_arg_dynarray {
 	struct format_field	*field;
 	struct print_arg	*index;
@@ -273,6 +279,7 @@ enum print_arg_type {
 	PRINT_FLAGS,
 	PRINT_SYMBOL,
 	PRINT_HEX,
+	PRINT_INT_ARRAY,
 	PRINT_TYPE,
 	PRINT_STRING,
 	PRINT_BSTRING,
@@ -292,6 +299,7 @@ struct print_arg {
 		struct print_arg_flags		flags;
 		struct print_arg_symbol		symbol;
 		struct print_arg_hex		hex;
+		struct print_arg_int_array	int_array;
 		struct print_arg_func		func;
 		struct print_arg_string		string;
 		struct print_arg_bitmask	bitmask;
-- 
1.9.1

Re: [PATCH v8 2/2] tools lib traceevent: Add support for __print_array()

[Steven Rostedt]

On Fri,  6 Mar 2015 18:35:18 +0000
Javi Merino <javi.merino@arm.com> wrote:

> Since 6ea22486ba46 ("tracing: Add array printing helper") trace can
> traces with variable element size arrays.  Add support to parse them.
> 
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>

Both patches look fine to me. You can add my:

Acked-by: Steven Rostedt <rostedt@goodmis.org>


> Acked-by: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Javi Merino <javi.merino@arm.com>
> ---
>  tools/lib/traceevent/event-parse.c | 93 ++++++++++++++++++++++++++++++++++++++
>  tools/lib/traceevent/event-parse.h |  8 ++++
>  2 files changed, 101 insertions(+)
> 


> +		if (arg->int_array.field->type == PRINT_DYNAMIC_ARRAY) {
> +			unsigned long offset;
> +			struct format_field *field =
> +				arg->int_array.field->dynarray.field;
> +			offset = pevent_read_number(pevent,
> +						    data + field->offset,
> +						    field->size);
> +			num = data + (offset & 0xffff);

Unrelated to this patch set, but we really should make that 0xffff a
named define. Something like this perhaps?

#define DYNAMIC_OFFSET_MASK 0xffff
#define DYNAMIC_LENGTH_SHIFT 16

and even add:

#define dynamic_offset(num) ((num) & DYNAMIC_OFFSET_MASK)
#define dynamic_length(num) ((num) >> DYNAMIC_LENGTH_SHIFT)

and use these macros instead.

Again, this has nothing to do with the acceptance of this patch set.
Just something that this patch set reminds me that we should do.

-- Steve

> +		} else {
> +			field = arg->int_array.field->field.field;
> +			if (!field) {
> +				str = arg->int_array.field->field.name;
> +				field = pevent_find_any_field(event, str);
> +				if (!field)
> +					goto out_warning_field;
> +				arg->int_array.field->field.field = field;
> +			}
> +			num = data + field->offset;