From: Peter Zijlstra <peterz@infradead.org>
To: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>,
Eranian Stephane <eranian@google.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Dapeng Mi <dapeng1.mi@intel.com>, Zide Chen <zide.chen@intel.com>,
Falcon Thomas <thomas.falcon@intel.com>,
Xudong Hao <xudong.hao@intel.com>
Subject: Re: [PATCH] perf: Fix 0 count issue of cpu-clock
Date: Tue, 18 Nov 2025 11:50:06 +0100 [thread overview]
Message-ID: <20251118105006.GO3245006@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20251112080526.3971392-1-dapeng1.mi@linux.intel.com>
On Wed, Nov 12, 2025 at 04:05:26PM +0800, Dapeng Mi wrote:
> Currently cpu-clock event always returns 0 count, e.g.,
>
> perf stat -e cpu-clock -- sleep 1
>
> Performance counter stats for 'sleep 1':
> 0 cpu-clock # 0.000 CPUs utilized
> 1.002308394 seconds time elapsed
>
> The root cause is the commit 'bc4394e5e79c ("perf: Fix the throttle
> error of some clock events")' adds PERF_EF_UPDATE flag check before
> calling cpu_clock_event_update() to update the count, however the
> PERF_EF_UPDATE flag is never set when the cpu-clock event is stopped in
> counting mode (pmu->dev() -> cpu_clock_event_del() ->
> cpu_clock_event_stop()). This leads to the cpu-clock event count is
> never updated.
>
> To fix this issue, force to set PERF_EF_UPDATE flag for cpu-clock event
> just like what task-clock does. Besides, or flags with PERF_EF_UPDATE
> for task-clock although currently the flags argument would always be 0.
>
> Fixes: bc4394e5e79c ("perf: Fix the throttle error of some clock events")
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> ---
So I'm forever struggling to find what tree a particular commit is in,
but afaict the above fingered commit is already in Linus' tree and so
this should go to perf/urgent, right?
next prev parent reply other threads:[~2025-11-18 10:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-12 8:05 Dapeng Mi
2025-11-12 16:42 ` Ian Rogers
2025-11-17 17:04 ` Ian Rogers
2025-11-18 1:43 ` Namhyung Kim
2025-11-18 10:50 ` Peter Zijlstra [this message]
2025-11-18 11:03 ` Peter Zijlstra
2025-11-18 11:04 ` Peter Zijlstra
2025-11-18 11:22 ` Mi, Dapeng
2025-11-18 11:24 ` Peter Zijlstra
2025-12-05 23:44 ` Ian Rogers
2025-12-08 5:16 ` Mi, Dapeng
2025-11-20 9:47 ` [tip: perf/urgent] " tip-bot2 for Dapeng Mi
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