On Mon, Sep 16, 2019 at 06:41:22AM -0700, [email protected] wrote:
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index 71f3086a8adc..7ec0f350d2ac 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -2262,6 +2262,11 @@ static int icl_set_topdown_event_period(struct
> perf_event *event)
> local64_set(&hwc->period_left, 0);
> }
>
> + if ((hwc->saved_slots) && is_first_topdown_event_in_group(event)) {
> + wrmsrl(MSR_CORE_PERF_FIXED_CTR3, hwc->saved_slots);
> + wrmsrl(MSR_PERF_METRICS, hwc->saved_metric);
> + }
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 61448c19a132..c125068f2e16 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -133,6 +133,9 @@ struct hw_perf_event {
>
> struct hw_perf_event_extra extra_reg;
> struct hw_perf_event_extra branch_reg;
> +
> + u64 saved_slots;
> + u64 saved_metric;
> };
> struct { /* software */
> struct hrtimer hrtimer;
Normal counters save their counter value in hwc->period_left, why does
slots need a new word for that?
And since using METRIC means non-sampling, why can't we stick that
saved_metric field in one of the unused sampling fields?
ISTR asking this before...
