perf evsel: Override attr->sample_period for non-libpfm4 events

A previous patch preventing "attr->sample_period" values from being
overridden in pfm events changed a related behaviour in arm-spe.

Before said patch:

  perf record -c 10000 -e arm_spe_0// -- sleep 1

Would yield an SPE event with period=10000. After the patch, the period
in "-c 10000" was being ignored because the arm-spe code initializes
sample_period to a non-zero value.

This patch restores the previous behaviour for non-libpfm4 events.

Fixes: d101152eb3d9 (“perf record: Prevent override of attr->sample_period for libpfm4 events”)
Reported-by: Chase Conklin <chase.conklin@arm.com>
Signed-off-by: German Gomez <german.gomez@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220118144054.2541-1-german.gomez@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index fb0a2debf01546187680c8b214296ebb6bdd0d13..22d3267ce29413dfd212c55b09bca871d0367d15 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1064,6 +1064,17 @@ void __weak arch_evsel__fixup_new_cycles(struct perf_event_attr *attr __maybe_un
 {
 }
 
+static void evsel__set_default_freq_period(struct record_opts *opts,
+                                          struct perf_event_attr *attr)
+{
+       if (opts->freq) {
+               attr->freq = 1;
+               attr->sample_freq = opts->freq;
+       } else {
+               attr->sample_period = opts->default_interval;
+       }
+}
+
 /*
  * The enable_on_exec/disabled value strategy:
  *
@@ -1130,14 +1141,12 @@ 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) {
-               if (opts->freq) {
-                       attr->freq              = 1;
-                       attr->sample_freq       = opts->freq;
-               } else {
-                       attr->sample_period = opts->default_interval;
-               }
-       }
+       if ((evsel->is_libpfm_event && !attr->sample_period) ||
+           (!evsel->is_libpfm_event && (!attr->sample_period ||
+                                        opts->user_freq != UINT_MAX ||
+                                        opts->user_interval != ULLONG_MAX)))
+               evsel__set_default_freq_period(opts, attr);
+
        /*
         * If attr->freq was set (here or earlier), ask for period
         * to be sampled.