From: German Gomez <german.gomez@arm.com>
To: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
acme@kernel.org
Cc: German Gomez <german.gomez@arm.com>,
Chase Conklin <chase.conklin@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>, Ian Rogers <irogers@google.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Stephane Eranian <eranian@google.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH v2] perf record/arm-spe: Override attr->sample_period for non-libpfm4 events
Date: Tue, 18 Jan 2022 14:40:54 +0000 [thread overview]
Message-ID: <20220118144054.2541-1-german.gomez@arm.com> (raw)
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.
Reported-by: Chase Conklin <chase.conklin@arm.com>
Fixes: ae5dcc8abe31 (“perf record: Prevent override of attr->sample_period for libpfm4 events”)
Signed-off-by: German Gomez <german.gomez@arm.com>
---
As suggested by Arnaldo, this v2 doesn't include a test in order to not
block this fix for longer than necessary. So the test can be sent as a
separate submission later.
Changes since v1.
- Update commit message (James Clark)
---
tools/perf/util/evsel.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index a59fb2ecb84e..86ab038f020f 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1065,6 +1065,17 @@ 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:
*
@@ -1131,14 +1142,12 @@ 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.
--
2.25.1
next reply other threads:[~2022-01-18 14:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 14:40 German Gomez [this message]
2022-01-22 20:15 ` [PATCH v2] perf record/arm-spe: Override attr->sample_period for non-libpfm4 events Arnaldo Carvalho de Melo
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