From 82bf311e15d22e2fa45423b1fb4a21cf925381fe Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 26 Jul 2017 14:02:06 +0200 Subject: perf stat: Use group read for event groups Make perf stat use group read if there are groups defined. The group read will get the values for all member of groups within a single syscall instead of calling read syscall for every event. We can see considerable less amount of kernel cycles spent on single group read, than reading each event separately, like for following perf stat command: # perf stat -e {cycles,instructions} -I 10 -a sleep 1 Monitored with "perf stat -r 5 -e '{cycles:u,cycles:k}'" Before: 24,325,676 cycles:u 297,040,775 cycles:k 1.038554134 seconds time elapsed After: 25,034,418 cycles:u 158,256,395 cycles:k 1.036864497 seconds time elapsed The perf_evsel__open fallback changes contributed by Andi Kleen. Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170726120206.9099-4-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/counts.h | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/perf/util/counts.h') diff --git a/tools/perf/util/counts.h b/tools/perf/util/counts.h index 34d8baaf558a..cb45a6aecf9d 100644 --- a/tools/perf/util/counts.h +++ b/tools/perf/util/counts.h @@ -12,6 +12,7 @@ struct perf_counts_values { }; u64 values[3]; }; + bool loaded; }; struct perf_counts { -- cgit v1.2.3