From: German Gomez german.gomez@arm.com
commit 3606c0e1a1050d397ad759a62607e419fd8b0ccb upstream.
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: ae5dcc8abe31 (“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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/perf/util/evsel.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)
--- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1064,6 +1064,17 @@ void __weak arch_evsel__fixup_new_cycles { }
+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, * 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.