[PATCH v0] lockstat: Add documentation on contention and contenting points

From: Daniel Wagner
Date: Tue Jan 13 2015 - 10:06:57 EST


Signed-off-by: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
---

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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/