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| author | Ingo Molnar <mingo@elte.hu> | 2011-04-28 18:17:11 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-04-28 08:39:39 +0200 |
| commit | f9cef0a90c4e7637f1ec98474a1a099aec45eb65 (patch) | |
| tree | 6a7b6bd456a274070f83d75fa1e7f97d90f32e8e /tools/perf | |
| parent | perf event, x86: Use better stalled cycles metric (diff) | |
| download | linux-f9cef0a90c4e7637f1ec98474a1a099aec45eb65.tar.xz linux-f9cef0a90c4e7637f1ec98474a1a099aec45eb65.zip | |
perf stat: Add --sync/-S option
--sync will tell perf stat to run sync() before starting a command.
This allows IO-heavy tests to be used with --repeat, without one
iteration impacting the other.
Elapsed time will stabilize for example:
before: 3.971525714 seconds time elapsed ( +- 8.56% )
after: 3.211098537 seconds time elapsed ( +- 1.52% )
So measurements will be more accurate.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-7y40wib8n1eqio7hjpn1dsrm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools/perf')
| -rw-r--r-- | tools/perf/builtin-stat.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 003caa857a44..5658a770dbd7 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -128,6 +128,7 @@ static pid_t target_tid = -1; static pid_t child_pid = -1; static bool null_run = false; static bool detailed_run = false; +static bool sync_run = false; static bool big_num = true; static int big_num_opt = -1; static const char *cpu_list; @@ -819,6 +820,8 @@ static const struct option options[] = { "null run - dont start any counters"), OPT_BOOLEAN('d', "detailed", &detailed_run, "detailed run - start a lot of events"), + OPT_BOOLEAN('S', "sync", &sync_run, + "call sync() before starting a run"), OPT_CALLBACK_NOOPT('B', "big-num", NULL, NULL, "print large numbers with thousands\' separators", stat__set_big_num), @@ -944,6 +947,10 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used) for (run_idx = 0; run_idx < run_count; run_idx++) { if (run_count != 1 && verbose) fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1); + + if (sync_run) + sync(); + status = run_perf_stat(argc, argv); } |