Re: [PATCH v6 03/13] alpha/perf: clear PERF_HES_UPTODATE when an event starts counting

[sashiko-bot@kernel.org]

> alpha_pmu_add() sets PERF_HES_UPTODATE and maybe_change_configuration()
> then programs and enables the counter, but nothing clears the flag until
> the first alpha_pmu_start(). In that window alpha_pmu_stop() with
> PERF_EF_UPDATE skips the count update, because the flag claims the count
> is current. Since the next reload rewrites the counter, everything
> counted since the event was added is lost.
> 
> perf_adjust_freq_unthr_events() does this on the first tick
> after an event in frequency mode is scheduled in, which is the default
> for perf record, and it then sees no count to adjust the period with.
> 
> Clear the flag where the event starts counting. alpha_pmu_add() cannot
> do it, since the event is not programmed until the PMU is enabled, and
> stopping it before then must not read the counter.
> 
> Fixes: a4eaf7f14675 ("perf: Rework the PMU methods")
> Assisted-by: Claude:claude-opus-5-5
> Reviewed-by: Magnus Lindholm <linmag7@gmail.com>
> Tested-by: Magnus Lindholm <linmag7@gmail.com>
> Signed-off-by: Matt Turner <mattst88@gmail.com>

Sashiko has reviewed this patch and found no issues.

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