perf_counter: Provide a way to enable counters on exec
This provides a way to mark a counter to be enabled on the next
exec. This is useful for measuring the total activity of a
program without including overhead from the process that
launches it.
This also changes the perf stat command to use this new
facility.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <19017.43927.838745.689203@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 201ef23..2e03524 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -116,8 +116,9 @@
fd[cpu][counter], strerror(errno));
}
} else {
- attr->inherit = inherit;
- attr->disabled = 1;
+ attr->inherit = inherit;
+ attr->disabled = 1;
+ attr->enable_on_exec = 1;
fd[0][counter] = sys_perf_counter_open(attr, pid, -1, -1, 0);
if (fd[0][counter] < 0 && verbose)
@@ -262,7 +263,6 @@
* Enable counters and exec the command:
*/
t0 = rdclock();
- prctl(PR_TASK_PERF_COUNTERS_ENABLE);
close(go_pipe[1]);
wait(&status);