Messages in this thread Patch in this message | | | Date | Sat, 27 Jun 2009 04:31:25 GMT | From | tip-bot for Ingo Molnar <> | Subject | [tip:perfcounters/urgent] perf stat: Add -n/--null option to run without counters |
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Commit-ID: 0cfb7a13b8e4e0afd4b856156ab16a182de7505b Gitweb: http://git.kernel.org/tip/0cfb7a13b8e4e0afd4b856156ab16a182de7505b Author: Ingo Molnar <mingo@elte.hu> AuthorDate: Sat, 27 Jun 2009 06:10:30 +0200 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Sat, 27 Jun 2009 06:11:24 +0200
perf stat: Add -n/--null option to run without counters
Allow a no-counters run. This can be useful to measure just elapsed wall-clock time - or to assess the raw overhead of perf stat itself, without running any counters.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- tools/perf/builtin-stat.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 8420ec5..cdcd058 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -70,6 +70,7 @@ static int run_count = 1; static int inherit = 1; static int scale = 1; static int target_pid = -1; +static int null_run = 0; static int fd[MAX_NR_CPUS][MAX_COUNTERS]; @@ -461,6 +462,8 @@ static const struct option options[] = { "be more verbose (show counter open errors, etc)"), OPT_INTEGER('r', "repeat", &run_count, "repeat command and print average + stddev (max: 100)"), + OPT_BOOLEAN('n', "null", &null_run, + "null run - dont start any counters"), OPT_END() }; @@ -476,7 +479,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix) if (run_count <= 0 || run_count > MAX_RUN) usage_with_options(stat_usage, options); - if (!nr_counters) + if (!null_run && !nr_counters) nr_counters = 8; nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
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