Messages in this thread | | | Date | Wed, 13 Mar 2024 11:11:42 +0000 | Subject | Re: [PATCH 05/10] drivers/perf: Use PERF_PMU_CAP_NO_SAMPLING consistently | From | James Clark <> |
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On 12/03/2024 17:34, Robin Murphy wrote: > Our system PMUs fundamentally cannot support the current notion of > sampling events, so now that the core capability has been clarified, > apply it consistently and purge yet more boilerplate. > > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > drivers/perf/alibaba_uncore_drw_pmu.c | 6 +----- > drivers/perf/amlogic/meson_ddr_pmu_core.c | 3 ++- > drivers/perf/arm-cci.c | 3 ++- > drivers/perf/arm-ccn.c | 12 +----------- > drivers/perf/arm-cmn.c | 3 ++- > drivers/perf/arm_cspmu/arm_cspmu.c | 17 ++++------------- > drivers/perf/arm_dmc620_pmu.c | 4 ++-- > drivers/perf/arm_dsu_pmu.c | 12 +----------- > drivers/perf/arm_smmuv3_pmu.c | 6 +----- > drivers/perf/cxl_pmu.c | 3 ++- > drivers/perf/dwc_pcie_pmu.c | 5 +---- > drivers/perf/fsl_imx8_ddr_perf.c | 3 ++- > drivers/perf/fsl_imx9_ddr_perf.c | 3 ++- > drivers/perf/hisilicon/hisi_pcie_pmu.c | 4 ++-- > drivers/perf/hisilicon/hisi_uncore_pmu.c | 3 ++- > drivers/perf/hisilicon/hns3_pmu.c | 4 ++-- > drivers/perf/marvell_cn10k_ddr_pmu.c | 6 +----- > drivers/perf/qcom_l2_pmu.c | 7 +------ > drivers/perf/qcom_l3_pmu.c | 7 +------ > drivers/perf/thunderx2_pmu.c | 4 ++-- > drivers/perf/xgene_pmu.c | 4 ++-- > 21 files changed, 36 insertions(+), 83 deletions(-) > [...] > > diff --git a/drivers/perf/arm-ccn.c b/drivers/perf/arm-ccn.c > index ce26bb773a56..4114349e62dd 100644 > --- a/drivers/perf/arm-ccn.c > +++ b/drivers/perf/arm-ccn.c > @@ -713,7 +713,6 @@ static void arm_ccn_pmu_event_release(struct perf_event *event) > static int arm_ccn_pmu_event_init(struct perf_event *event) > { > struct arm_ccn *ccn; > - struct hw_perf_event *hw = &event->hw; > u32 node_xp, type, event_id; > int valid; > int i; > @@ -721,16 +720,6 @@ static int arm_ccn_pmu_event_init(struct perf_event *event) > > ccn = pmu_to_arm_ccn(event->pmu); > > - if (hw->sample_period) { > - dev_dbg(ccn->dev, "Sampling not supported!\n"); > - return -EOPNOTSUPP; > - } > - > - if (has_branch_stack(event)) { > - dev_dbg(ccn->dev, "Can't exclude execution levels!\n"); > - return -EINVAL; > - } > -
[...]
> diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c > index f5ea5acaf2f3..3424d165795c 100644 > --- a/drivers/perf/arm_dsu_pmu.c > +++ b/drivers/perf/arm_dsu_pmu.c > @@ -544,23 +544,12 @@ static int dsu_pmu_event_init(struct perf_event *event) > { > struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu); > > - /* We don't support sampling */ > - if (is_sampling_event(event)) { > - dev_dbg(dsu_pmu->pmu.dev, "Can't support sampling events\n"); > - return -EOPNOTSUPP; > - } > - > /* We cannot support task bound events */ > if (event->cpu < 0 || event->attach_state & PERF_ATTACH_TASK) { > dev_dbg(dsu_pmu->pmu.dev, "Can't support per-task counters\n"); > return -EINVAL; > } > > - if (has_branch_stack(event)) { > - dev_dbg(dsu_pmu->pmu.dev, "Can't support filtering\n"); > - return -EINVAL; > - } > -
I'm assuming that this and the other has_branch_stack() check were removed because branch stacks don't actually do anything unless sampling is enabled?
It's a small difference that there is now no error message if you ask for branch stacks, but it wouldn't have done anything anyway? I suppose this error message was also not applied very consistently across the different devices.
James
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