linux-kernel - [PATCH v2] perf script: add min, max to futex-contention

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Date:   Tue, 22 Sep 2020 22:09:22 +0200
From:   Hagen Paul Pfeifer <hagen@...u.net>
To:     linux-kernel@...r.kernel.org
Cc:     Hagen Paul Pfeifer <hagen@...u.net>,
        Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH v2] perf script: add min, max to futex-contention

Average is quite informative, but the outliners - especially max - are
also of interest.

Before:

mutex-locker[793299] lock 5637ec61e080 contended 3400 times, 446 avg ns
mutex-locker[793301] lock 5637ec61e080 contended 3563 times, 385 avg ns
mutex-locker[793300] lock 5637ec61e080 contended 3110 times, 1855 avg ns

After:

mutex-locker[795251] lock 55b14e6dd080 contended 3853 times, 1279 avg ns [max: 12270 ns, min 340 ns]
mutex-locker[795253] lock 55b14e6dd080 contended 2911 times, 518 avg ns [max: 51660261 ns, min 347 ns]
mutex-locker[795252] lock 55b14e6dd080 contended 3843 times, 385 avg ns [max: 24323998 ns, min 338 ns]

Signed-off-by: Hagen Paul Pfeifer <hagen@...u.net>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
---

v2: nanosecond, not microseconds

 tools/perf/scripts/python/futex-contention.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/scripts/python/futex-contention.py b/tools/perf/scripts/python/futex-contention.py
index c440f02627dd..7e884d46f920 100644
--- a/tools/perf/scripts/python/futex-contention.py
+++ b/tools/perf/scripts/python/futex-contention.py
@@ -53,5 +53,5 @@ def trace_begin():
 def trace_end():
     for (tid, lock) in lock_waits:
         min, max, avg, count = lock_waits[tid, lock]
-        print("%s[%d] lock %x contended %d times, %d avg ns" %
-              (process_names[tid], tid, lock, count, avg))
+        print("%s[%d] lock %x contended %d times, %d avg ns [max: %d ns, min %d ns]" %
+              (process_names[tid], tid, lock, count, avg, max, min))
-- 
2.28.0