From 0cfb7a13b8e4e0afd4b856156ab16a182de7505b Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 27 Jun 2009 06:10:30 +0200 Subject: 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 Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo LKML-Reference: Signed-off-by: Ingo Molnar --- tools/perf/builtin-stat.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 8420ec58950..cdcd058fac0 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); -- cgit v1.2.3