[PATCH v3 2/2] perf stat: Stop repeating when ref_perf_stat() returns -1

From: Levi Yun
Date: Fri Sep 13 2024 - 06:16:06 EST


Exit when run_perf_stat() returns an error to avoid continuously
repeating the same error message. It's not expected that COUNTER_FATAL
or internal errors are recoverable so there's no point in retrying.

This fixes the following flood of error messages for permission issues,
for example when perf_event_paranoid==3:
perf stat -r 1044 -- false

Error:
Access to performance monitoring and observability operations is limited.
...
Error:
Access to performance monitoring and observability operations is limited.
...
(repeating for 1044 times).

Signed-off-by: Levi Yun <yeoreum.yun@xxxxxxx>
---
tools/perf/builtin-stat.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 954eb37ce7b8..d25528ea7e40 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2875,7 +2875,19 @@ int cmd_stat(int argc, const char **argv)
evlist__reset_prev_raw_counts(evsel_list);

status = run_perf_stat(argc, argv, run_idx);
- if (forever && status != -1 && !interval) {
+
+ /*
+ * Returns -1 for fatal errors which signifies to not continue
+ * when in repeat mode.
+ *
+ * Returns < -1 error codes when stat record is used. These
+ * result in the stat information being displayed, but writing
+ * to the file fails and is non fatal.
+ */
+ if (status == -1)
+ break;
+
+ if (forever && !interval) {
print_counters(NULL, argc, argv);
perf_stat__reset_stats();
}
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}