Re: [PATCH V4 03/16] perf, x86: use context switch callback to flush LBR stack

[Peter Zijlstra]

On Mon, Jun 30, 2014 at 04:50:40PM +0800, Yan, Zheng wrote:
> @@ -185,6 +185,23 @@ void intel_pmu_lbr_enable(struct perf_event *event)
>               return;
>  
>       /*
> +      * It is necessary to flush the stack on context switch. This happens
> +      * when the branch stack does not tag its entries with the pid of the
> +      * current task.

Did you mean to say: "This happens _because_ the branch stack does not
tag its entries with the pid of the current task." ?

> +      */
> +     if (sched_in) {
> +             intel_pmu_lbr_reset();
> +             cpuc->lbr_context = ctx;
> +     }
> +}

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