2023-07-10 12:28:27

by James Clark

Subject: [PATCH 2/4] perf/x86: Remove unused PERF_PMU_CAP_HETEROGENEOUS_CPUS capability

Since commit bd2756811766 ("perf: Rewrite core context handling") the
relationship between perf_event_context and PMUs has changed so that
the error scenario that PERF_PMU_CAP_HETEROGENEOUS_CPUS originally
silenced no longer exists.

Remove the capability to avoid confusion that it actually influences
any perf core behavior. This change should be a no-op.

Signed-off-by: James Clark <[email protected]>
---
arch/x86/events/core.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 9d248703cbdd..2353aaf0b248 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2168,7 +2168,6 @@ static int __init init_hw_perf_events(void)
hybrid_pmu->pmu = pmu;
hybrid_pmu->pmu.type = -1;
hybrid_pmu->pmu.attr_update = x86_pmu.attr_update;
- hybrid_pmu->pmu.capabilities |= PERF_PMU_CAP_HETEROGENEOUS_CPUS;
hybrid_pmu->pmu.capabilities |= PERF_PMU_CAP_EXTENDED_HW_TYPE;

err = perf_pmu_register(&hybrid_pmu->pmu, hybrid_pmu->name,
--
2.34.1

2023-07-10 17:09:35

by Ian Rogers

Subject: Re: [PATCH 2/4] perf/x86: Remove unused PERF_PMU_CAP_HETEROGENEOUS_CPUS capability

On Mon, Jul 10, 2023 at 5:22 AM James Clark <[email protected]> wrote:
>
> Since commit bd2756811766 ("perf: Rewrite core context handling") the
> relationship between perf_event_context and PMUs has changed so that
> the error scenario that PERF_PMU_CAP_HETEROGENEOUS_CPUS originally
> silenced no longer exists.
>
> Remove the capability to avoid confusion that it actually influences
> any perf core behavior. This change should be a no-op.
>
> Signed-off-by: James Clark <[email protected]>

Acked-by: Ian Rogers <[email protected]>

Thanks,
Ian

> ---
> arch/x86/events/core.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index 9d248703cbdd..2353aaf0b248 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -2168,7 +2168,6 @@ static int __init init_hw_perf_events(void)
> hybrid_pmu->pmu = pmu;
> hybrid_pmu->pmu.type = -1;
> hybrid_pmu->pmu.attr_update = x86_pmu.attr_update;
> - hybrid_pmu->pmu.capabilities |= PERF_PMU_CAP_HETEROGENEOUS_CPUS;
> hybrid_pmu->pmu.capabilities |= PERF_PMU_CAP_EXTENDED_HW_TYPE;
>
> err = perf_pmu_register(&hybrid_pmu->pmu, hybrid_pmu->name,
> --
> 2.34.1
>