Messages in this thread | | | From | Peter Newman <> | Date | Tue, 16 Aug 2022 19:00:29 +0200 | Subject | Re: [PATCH v3] perf/arm: adjust hwevents mappings on boot |
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On Tue, Aug 16, 2022 at 4:18 PM Mark Rutland <mark.rutland@arm.com> wrote: > On big.LITTLE systems this is array is shared by multiple PMUs, so this cannot > be altered based on a single PMU. > > Rather than applying a fixup, could we special-case this at mapping time? > > Does the following work for you? > > Thanks > Mark. > > ---->8---- > From 6cf78ec72194296e8d0c87572b81f2b02a097918 Mon Sep 17 00:00:00 2001 > From: Mark Rutland <mark.rutland@arm.com> > Date: Tue, 16 Aug 2022 15:16:23 +0100 > Subject: [PATCH] arm64: pmuv3: dynamically map > PERF_COUNT_HW_BRANCH_INSTRUCTIONS > > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Peter Newman <peternewman@google.com> Tested-by: Peter Newman <peternewman@google.com>
> --- > arch/arm64/kernel/perf_event.c | 27 +++++++++++++++++++++++---- > 1 file changed, 23 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c > index cb69ff1e61380..0435adee5cab8 100644 > --- a/arch/arm64/kernel/perf_event.c > +++ b/arch/arm64/kernel/perf_event.c > @@ -45,7 +45,6 @@ static const unsigned armv8_pmuv3_perf_map[PERF_COUNT_HW_MAX] = { > [PERF_COUNT_HW_INSTRUCTIONS] = ARMV8_PMUV3_PERFCTR_INST_RETIRED, > [PERF_COUNT_HW_CACHE_REFERENCES] = ARMV8_PMUV3_PERFCTR_L1D_CACHE, > [PERF_COUNT_HW_CACHE_MISSES] = ARMV8_PMUV3_PERFCTR_L1D_CACHE_REFILL, > - [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = ARMV8_PMUV3_PERFCTR_PC_WRITE_RETIRED, > [PERF_COUNT_HW_BRANCH_MISSES] = ARMV8_PMUV3_PERFCTR_BR_MIS_PRED, > [PERF_COUNT_HW_BUS_CYCLES] = ARMV8_PMUV3_PERFCTR_BUS_CYCLES, > [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = ARMV8_PMUV3_PERFCTR_STALL_FRONTEND, > @@ -1050,6 +1049,28 @@ static void armv8pmu_reset(void *info) > armv8pmu_pmcr_write(pmcr); > } > > +static int __armv8_pmuv3_map_event_id(struct arm_pmu *armpmu, > + struct perf_event *event) > +{ > + if (event->attr.type == PERF_TYPE_HARDWARE && > + event->attr.config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) { > + > + if (test_bit(ARMV8_PMUV3_PERFCTR_PC_WRITE_RETIRED, > + armpmu->pmceid_bitmap)) > + return ARMV8_PMUV3_PERFCTR_PC_WRITE_RETIRED; > + > + if (test_bit(ARMV8_PMUV3_PERFCTR_BR_RETIRED, > + armpmu->pmceid_bitmap)) > + return ARMV8_PMUV3_PERFCTR_BR_RETIRED; > + > + return HW_OP_UNSUPPORTED; > + } > + > + return armpmu_map_event(event, &armv8_pmuv3_perf_map, > + &armv8_pmuv3_perf_cache_map, > + ARMV8_PMU_EVTYPE_EVENT); > +} > + > static int __armv8_pmuv3_map_event(struct perf_event *event, > const unsigned (*extra_event_map) > [PERF_COUNT_HW_MAX], > @@ -1061,9 +1082,7 @@ static int __armv8_pmuv3_map_event(struct perf_event *event, > int hw_event_id; > struct arm_pmu *armpmu = to_arm_pmu(event->pmu); > > - hw_event_id = armpmu_map_event(event, &armv8_pmuv3_perf_map, > - &armv8_pmuv3_perf_cache_map, > - ARMV8_PMU_EVTYPE_EVENT); > + hw_event_id = __armv8_pmuv3_map_event_id(armpmu, event); > > if (armv8pmu_event_is_64bit(event)) > event->hw.flags |= ARMPMU_EVT_64BIT; > -- > 2.30.2 >
Hi Mark,
I can confirm that your patch fixes the issue we saw.
Thank you for coming back with this quickly, it looks like a better solution to me.
Which branch were you going to apply it to?
Thanks! -Peter
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