[PATCH] perf stat: Do not show stats if workload fails

From: David Ahern
Date: Fri Dec 20 2013 - 00:52:44 EST


Currently perf-stat attempts to show counter stats even if the workload
is bogus:

$ perf stat -- foo
foo: No such file or directory

Performance counter stats for 'foo':

<not counted> task-clock
<not counted> context-switches
<not counted> cpu-migrations
<not counted> page-faults
<not counted> cycles
<not counted> stalled-cycles-frontend
<not counted> stalled-cycles-backend
<not counted> instructions
<not counted> branches
<not counted> branch-misses

0.009769943 seconds time elapsed

It is impossible to differentiate all the failure modes, but it seems
reasonable that if the workload handling fails, perf-stat should not try
to print stats.

With this change:

$ perf stat -v -- foo
Failed to start workload

Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
---
tools/perf/builtin-stat.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index dab98b50c9fe..d6e6a0b031d9 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -586,7 +586,11 @@ static int __run_perf_stat(int argc, const char **argv)
clock_gettime(CLOCK_MONOTONIC, &ref_time);

if (forks) {
- perf_evlist__start_workload(evsel_list);
+ if (perf_evlist__start_workload(evsel_list) != 0) {
+ pr_err("Failed to start workload\n");
+ return -1;
+ }
+
handle_initial_delay();

if (interval) {
@@ -1793,7 +1797,10 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
run_idx + 1);

status = run_perf_stat(argc, argv);
- if (forever && status != -1) {
+ if (status < 0)
+ break;
+
+ if (forever) {
print_stat(argc, argv);
perf_stat__reset_stats(evsel_list);
}
--
1.8.3.4 (Apple Git-47)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/