Messages in this thread | | | From | Ian Rogers <> | Date | Mon, 10 Jul 2023 09:04:40 -0700 | Subject | Re: [PATCH 1/4] arm_pmu: Add PERF_PMU_CAP_EXTENDED_HW_TYPE capability |
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On Mon, Jul 10, 2023 at 5:22 AM James Clark <james.clark@arm.com> wrote: > > This capability gives us the ability to open PERF_TYPE_HARDWARE and > PERF_TYPE_HW_CACHE events on a specific PMU for free. All the > implementation is contained in the Perf core and tool code so no change > to the Arm PMU driver is needed. > > The following basic use case now results in Perf opening the event on > all PMUs rather than picking only one in an unpredictable way: > > $ perf stat -e cycles -- taskset --cpu-list 0,1 stress -c 2 > > Performance counter stats for 'taskset --cpu-list 0,1 stress -c 2': > > 963279620 armv8_cortex_a57/cycles/ (99.19%) > 752745657 armv8_cortex_a53/cycles/ (94.80%) > > Fixes: 55bcf6ef314a ("perf: Extend PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE") > Suggested-by: Ian Rogers <irogers@google.com> > Signed-off-by: James Clark <james.clark@arm.com>
Acked-by: Ian Rogers <irogers@google.com>
Thanks, Ian
> --- > drivers/perf/arm_pmu.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index 277e29fbd504..d8844a9461a2 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -875,8 +875,13 @@ struct arm_pmu *armpmu_alloc(void) > * configuration (e.g. big.LITTLE). This is not an uncore PMU, > * and we have taken ctx sharing into account (e.g. with our > * pmu::filter callback and pmu::event_init group validation). > + * > + * PERF_PMU_CAP_EXTENDED_HW_TYPE is required to open the legacy > + * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE events on a > + * specific PMU. > */ > - .capabilities = PERF_PMU_CAP_HETEROGENEOUS_CPUS | PERF_PMU_CAP_EXTENDED_REGS, > + .capabilities = PERF_PMU_CAP_HETEROGENEOUS_CPUS | PERF_PMU_CAP_EXTENDED_REGS | > + PERF_PMU_CAP_EXTENDED_HW_TYPE, > }; > > pmu->attr_groups[ARMPMU_ATTR_GROUP_COMMON] = > -- > 2.34.1 >
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