This is a note to let you know that I've just added the patch titled
perf evsel: Override attr->sample_period for non-libpfm4 events
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-evsel-override-attr-sample_period-for-non-libpfm4-events.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3606c0e1a1050d397ad759a62607e419fd8b0ccb Mon Sep 17 00:00:00 2001
From: German Gomez <german.gomez@xxxxxxx>
Date: Tue, 18 Jan 2022 14:40:54 +0000
Subject: perf evsel: Override attr->sample_period for non-libpfm4 events
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From: German Gomez <german.gomez@xxxxxxx>
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@xxxxxxx>
Signed-off-by: German Gomez <german.gomez@xxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: KP Singh <kpsingh@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Martin KaFai Lau <kafai@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Yonghong Song <yhs@xxxxxx>
Cc: bpf@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Link: http://lore.kernel.org/lkml/20220118144054.2541-1-german.gomez@xxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -1014,6 +1014,17 @@ struct evsel_config_term *__evsel__get_c
return found_term;
}
+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:
*
@@ -1080,14 +1091,12 @@ 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.
Patches currently in stable-queue which might be from german.gomez@xxxxxxx are
queue-5.10/perf-evsel-override-attr-sample_period-for-non-libpfm4-events.patch
