perf record: Prevent override of attr->sample_period for libpfm4 events

Before:

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

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

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

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

Signed-off-by: Stephane Eranian <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Athira Jajeev <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Yonghong Song <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Ian Rogers <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: Stephane Eranian

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;