From: sashiko-bot@kernel.org
To: "Dapeng Mi" <dapeng1.mi@linux.intel.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 02/15] perf/x86/intel: Reset active_fixed_ctrl_val on CPU teardown
Date: Mon, 28 Sep 2026 08:02:54 +0000 [thread overview]
Message-ID: <20260928080255.1013B1F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260928074309.898043-3-dapeng1.mi@linux.intel.com>
> cpuc->active_fixed_ctrl_val tracks the value currently programmed into
> MSR_CORE_PERF_FIXED_CTR_CTRL, and reprogramming is skipped when the new
> value matches the cached one.
>
> After a CPU offline/online cycle, MSR_CORE_PERF_FIXED_CTR_CTRL may return
> to its reset state, but active_fixed_ctrl_val may still hold the
> pre-offline value. If the next computed fixed_ctrl_val matches that stale
> cache entry, the MSR update is incorrectly skipped, leaving
> MSR_CORE_PERF_FIXED_CTR_CTRL uninitialized for fixed counters and
> resulting in errors in fixed counter counting or samplig.
>
> Clear active_fixed_ctrl_val and MSR_CORE_PERF_FIXED_CTR_CTRL during CPU
> teardown so MSR_CORE_PERF_FIXED_CTR_CTRL is always reprogrammed when the
> CPU comes back online.
>
> Fixes: fae9ebde9696 ("perf/x86/intel: Optimize FIXED_CTR_CTRL access")
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260928074309.898043-1-dapeng1.mi@linux.intel.com?part=2
next prev parent reply other threads:[~2026-09-28 8:02 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-28 7:42 [PATCH 00/15] perf/x86: Fix sampling bugs and relax slots-event grouping Dapeng Mi
2026-09-28 7:42 ` [PATCH 01/15] perf/x86/intel: Guard leader sibling walk on nr_siblings Dapeng Mi
2026-09-28 8:00 ` sashiko-bot
2026-09-28 7:42 ` [PATCH 02/15] perf/x86/intel: Reset active_fixed_ctrl_val on CPU teardown Dapeng Mi
2026-09-28 8:02 ` sashiko-bot [this message]
2026-09-28 7:42 ` [PATCH 03/15] perf/x86/intel: Reset active_pebs_data_cfg " Dapeng Mi
2026-09-28 8:07 ` sashiko-bot
2026-09-28 7:42 ` [PATCH 04/15] perf/x86/intel: Reset cached acr_cfg_b[] and cfg_c_val[] " Dapeng Mi
2026-09-28 8:01 ` sashiko-bot
2026-09-28 7:42 ` [PATCH 05/15] perf/x86/intel: Pass correct PEBS counter mask to no-drain update path Dapeng Mi
2026-09-28 7:58 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 06/15] perf/x86/intel: Limit PEBS counter iteration to valid array bounds Dapeng Mi
2026-09-28 8:00 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 07/15] perf/x86/intel: Reject SAMPLE_READ for no-counter-snapshot ACR events Dapeng Mi
2026-09-28 8:04 ` sashiko-bot
2026-09-29 6:08 ` Mi, Dapeng
2026-09-29 19:02 ` Falcon, Thomas
2026-09-30 1:12 ` Mi, Dapeng
2026-09-28 7:43 ` [PATCH 08/15] perf/x86/intel: Fix stale PEBS count without counter-group support Dapeng Mi
2026-09-28 8:02 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 09/15] perf/x86/intel: Refactor intel_pmu_drain_arch_pebs() Dapeng Mi
2026-09-28 7:57 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 10/15] perf/x86/intel: Refactor intel_pmu_drain_pebs_icl() Dapeng Mi
2026-09-28 7:59 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 11/15] perf/x86/intel: Fix invalid PEBS counts with counter-group support Dapeng Mi
2026-09-28 8:00 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 12/15] perf/x86/intel: Make ACR static_call update architectural Dapeng Mi
2026-09-28 8:02 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 13/15] perf/x86: Validate event type before topdown/mem-loads classification Dapeng Mi
2026-09-28 8:01 ` sashiko-bot
2026-09-28 7:43 ` [PATCH 14/15] perf/core: Add event_caps dependency flags Dapeng Mi
2026-09-28 8:05 ` sashiko-bot
2026-09-29 6:34 ` Mi, Dapeng
2026-09-28 7:43 ` [PATCH 15/15] perf/x86/intel: Allow Topdown metrics with a non-leader slots event Dapeng Mi
2026-09-28 8:12 ` sashiko-bot
2026-09-29 7:04 ` Mi, Dapeng
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