[PATCH] perf arm-spe: Report error if set frequency
Namhyung Kim
namhyung at kernel.org
Wed Feb 26 23:05:08 PST 2025
Hello,
On Mon, Feb 17, 2025 at 08:20:08AM +0000, Leo Yan wrote:
> On Wed, Feb 05, 2025 at 06:30:09PM +0000, Leo Yan wrote:
> > When users set the parameter '-F' to specify frequency for Arm SPE, the
> > tool reports error:
> >
> > perf record -F 1000 -e arm_spe_0// -- sleep 1
> > Error:
> > Invalid event (arm_spe_0//) in per-thread mode, enable system wide with '-a'.
> >
> > The output logs are confused and it does not give the correct reminding.
> > Arm SPE does not support frequency setting given it adopts a statistical
> > based approach.
> >
> > Alternatively, Arm SPE supports setting period. This commit adds a
> > for frequency setting. It reports error and reminds users to set period
> > instead.
> >
> > After:
> >
> > perf record -F 100 -e arm_spe_0// -- sleep 1
> > Arm SPE: Frequency is not supported. Check manual 'man perf-record' on how to set period.
> >
> > Signed-off-by: Leo Yan <leo.yan at arm.com>
>
> Gentle ping.
Sorry for the late reply.
Isn't it just -c <period> to set period for Arm SPE? If so, it'd be
better to say that explicitly.
Thanks,
Namhyung
>
> > ---
> > tools/perf/arch/arm64/util/arm-spe.c | 20 ++++++++++++++++++++
> > 1 file changed, 20 insertions(+)
> >
> > diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> > index 4301181b8e45..baef0812dc19 100644
> > --- a/tools/perf/arch/arm64/util/arm-spe.c
> > +++ b/tools/perf/arch/arm64/util/arm-spe.c
> > @@ -40,6 +40,19 @@ struct arm_spe_recording {
> > bool *wrapped;
> > };
> >
> > +/* Iterate config list to detect if the "freq" parameter is set */
> > +static bool arm_spe_is_set_freq(struct evsel *evsel)
> > +{
> > + struct evsel_config_term *term;
> > +
> > + list_for_each_entry(term, &evsel->config_terms, list) {
> > + if (term->type == EVSEL__CONFIG_TERM_FREQ)
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
> > /*
> > * arm_spe_find_cpus() returns a new cpu map, and the caller should invoke
> > * perf_cpu_map__put() to release the map after use.
> > @@ -389,6 +402,13 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
> > return -EINVAL;
> > }
> > opts->full_auxtrace = true;
> > +
> > + if (opts->user_freq != UINT_MAX ||
> > + arm_spe_is_set_freq(evsel)) {
> > + pr_err("Arm SPE: Frequency is not supported. "
> > + "Check manual 'man perf-record' on how to set period.\n");
> > + return -EINVAL;
> > + }
> > }
> > }
> >
> > --
> > 2.34.1
> >
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