Re: [PATCH] perf: Fix 0 count issue of cpu-clock

[Peter Zijlstra <peterz@infradead.org>]

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).