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X-CSE-ConnectionGUID: 18SD1lkQSiqYl4tKsmm5yQ== X-CSE-MsgGUID: Ic8gkgynQ7KzOzDsYfCNPw== X-IronPort-AV: E=McAfee;i="6800,10657,11616"; a="65414375" X-IronPort-AV: E=Sophos;i="6.19,314,1754982000"; d="scan'208";a="65414375" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2025 03:22:32 -0800 X-CSE-ConnectionGUID: +m502a7QQImov0dHMYxTbA== X-CSE-MsgGUID: +SLceNaBQWuQjelYYKboCg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,314,1754982000"; d="scan'208";a="191173168" Received: from dapengmi-mobl1.ccr.corp.intel.com (HELO [10.124.240.213]) ([10.124.240.213]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2025 03:22:27 -0800 Message-ID: Date: Tue, 18 Nov 2025 19:22:24 +0800 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] perf: Fix 0 count issue of cpu-clock To: Peter Zijlstra Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Ian Rogers , Adrian Hunter , Alexander Shishkin , Andi Kleen , Eranian Stephane , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Dapeng Mi , Zide Chen , Falcon Thomas , Xudong Hao References: <20251112080526.3971392-1-dapeng1.mi@linux.intel.com> <20251118110309.GP3245006@noisy.programming.kicks-ass.net> <20251118110417.GI4068168@noisy.programming.kicks-ass.net> Content-Language: en-US From: "Mi, Dapeng" In-Reply-To: <20251118110417.GI4068168@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/18/2025 7:04 PM, Peter Zijlstra wrote: > On Tue, Nov 18, 2025 at 12:03:09PM +0100, Peter Zijlstra wrote: >> On Wed, Nov 12, 2025 at 04:05:26PM +0800, Dapeng Mi wrote: >> >>> diff --git a/kernel/events/core.c b/kernel/events/core.c >>> index f6a08c73f783..77d3af5959c1 100644 >>> --- a/kernel/events/core.c >>> +++ b/kernel/events/core.c >>> @@ -11964,7 +11964,7 @@ static int cpu_clock_event_add(struct perf_event *event, int flags) >>> >>> static void cpu_clock_event_del(struct perf_event *event, int flags) >>> { >>> - cpu_clock_event_stop(event, flags); >>> + cpu_clock_event_stop(event, flags | PERF_EF_UPDATE); >>> } >>> >>> static void cpu_clock_event_read(struct perf_event *event) >>> @@ -12043,7 +12043,7 @@ static int task_clock_event_add(struct perf_event *event, int flags) >>> >>> static void task_clock_event_del(struct perf_event *event, int flags) >>> { >>> - task_clock_event_stop(event, PERF_EF_UPDATE); >>> + task_clock_event_stop(event, flags | PERF_EF_UPDATE); >>> } >> I think it can both just be: PERF_EF_UPDATE. The only pmu::del() caller >> hands in flags=0, but if there were to be flags added, we'd have to >> audit all del methods anyway. >> >> Also, the few comments we do have already note that ->del() must do >> ->stop(EF_UPDATE). > Updated patch now sits in queue/perf/urgent. Hi Peter, Thanks for merging. If we decide not to or the "flags", then the last sentence "Besides, or flags with PERF_EF_UPDATE for task-clock although currently the flags argument would always be 0." in the commit message should be dropped as well. :) https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?h=perf/urgent&id=cfaecad27435b4eb6a22bb9d008fec4984e03a21 Thanks, Dapeng Mi