diff mbox series

[v3,2/4] perf record: Prevent override of attr->sample_period for libpfm4 events

Message ID 20200912025655.1337192-3-irogers@google.com
State Not Applicable
Delegated to: BPF Maintainers
Headers show
Series Fixes for setting event freq/periods | expand

Commit Message

Ian Rogers Sept. 12, 2020, 2:56 a.m. UTC 
From: Stephane Eranian <eranian@google.com>

Before:
$ perf record -c 10000 --pfm-events=cycles:period=77777

Would yield a cycles event with period=10000, instead of 77777.

This was due to an ordering issue between libpfm4 parsing
the event string and perf record initializing the event.

This patch fixes the problem by preventing override for
events with attr->sample_period != 0 by the time
perf_evsel__config() is invoked. This seems to have been the
intent of the author.

Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/evsel.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 3e985016da7e..459b51e90063 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -976,8 +976,7 @@  void evsel__config(struct evsel *evsel, struct record_opts *opts,
 	 * We default some events to have a default interval. But keep
 	 * it a weak assumption overridable by the user.
 	 */
-	if (!attr->sample_period || (opts->user_freq != UINT_MAX ||
-				     opts->user_interval != ULLONG_MAX)) {
+	if (!attr->sample_period) {
 		if (opts->freq) {
 			attr->freq		= 1;
 			attr->sample_freq	= opts->freq;