Commit-ID: 0cfb7a13b8e4e0afd4b856156ab16a182de7505b
Gitweb: http://git.kernel.org/tip/0cfb7a13b8e4e0afd4b856156ab16a182de7505b
Author: Ingo Molnar <mingo@xxxxxxx>
AuthorDate: Sat, 27 Jun 2009 06:10:30 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
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@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
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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