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* [PATCH v0] lockstat: Add documentation on contention and contenting points
@ 2015-01-13 14:59 Daniel Wagner
  2015-01-28 19:13 ` Jonathan Corbet
  0 siblings, 1 reply; 2+ messages in thread
From: Daniel Wagner @ 2015-01-13 14:59 UTC (permalink / raw)
  To: linux-kernel; +Cc: Daniel Wagner, Peter Zijlstra, Ingo Molnar, Jonathan Corbet

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
---

I spent some time to figure out what I saw in /proc/lock_stat. Maybe
someone else has the same question.
---
 Documentation/locking/lockstat.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/locking/lockstat.txt b/Documentation/locking/lockstat.txt
index 7428773..568bbba 100644
--- a/Documentation/locking/lockstat.txt
+++ b/Documentation/locking/lockstat.txt
@@ -121,6 +121,11 @@ show the header with column descriptions. Lines 05-18 and 20-31 show the actual
 statistics. These statistics come in two parts; the actual stats separated by a
 short separator (line 08, 13) from the contention points.
 
+Lines 09-12 show the first 4 recorded contention points (the code
+which tries to get the lock) and lines 14-17 show the first 4 recorded
+contended points (the lock holder). It is possible that the max
+con-bounces point is missing in the statistics.
+
 The first lock (05-18) is a read/write lock, and shows two lines above the
 short separator. The contention points don't match the column descriptors,
 they have two: contentions and [<IP>] symbol. The second set of contention
-- 
2.1.0


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v0] lockstat: Add documentation on contention and contenting points
  2015-01-13 14:59 [PATCH v0] lockstat: Add documentation on contention and contenting points Daniel Wagner
@ 2015-01-28 19:13 ` Jonathan Corbet
  0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Corbet @ 2015-01-28 19:13 UTC (permalink / raw)
  To: Daniel Wagner; +Cc: linux-kernel, Peter Zijlstra, Ingo Molnar

On Tue, 13 Jan 2015 15:59:30 +0100
Daniel Wagner <daniel.wagner@bmw-carit.de> wrote:

> I spent some time to figure out what I saw in /proc/lock_stat. Maybe
> someone else has the same question.

I've applied this to the docs tree, thanks.

jon

^ permalink raw reply	[flat|nested] 2+ messages in thread

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