On Tue, May 21, 2019 at 02:40:50PM -0700, kan.li...@linux.intel.com wrote:
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index e9075d57853d..07ecfe75f0e6 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -91,16 +91,20 @@ u64 x86_perf_event_update(struct perf_event *event)
> new_raw_count) != prev_raw_count)
> goto again;
>
> - /*
> - * Now we have the new raw value and have updated the prev
> - * timestamp already. We can now calculate the elapsed delta
> - * (event-)time and add that to the generic event.
> - *
> - * Careful, not all hw sign-extends above the physical width
> - * of the count.
> - */
> - delta = (new_raw_count << shift) - (prev_raw_count << shift);
> - delta >>= shift;
> + if (unlikely(hwc->flags & PERF_X86_EVENT_UPDATE))
> + delta = x86_pmu.metric_update_event(event, new_raw_count);
> + else {
> + /*
> + * Now we have the new raw value and have updated the prev
> + * timestamp already. We can now calculate the elapsed delta
> + * (event-)time and add that to the generic event.
> + *
> + * Careful, not all hw sign-extends above the physical width
> + * of the count.
> + */
> + delta = (new_raw_count << shift) - (prev_raw_count << shift);
> + delta >>= shift;
> + }
>
> local64_add(delta, &event->count);
> local64_sub(delta, &hwc->period_left);
> @@ -1186,6 +1194,9 @@ int x86_perf_event_set_period(struct perf_event *event)
> if (idx == INTEL_PMC_IDX_FIXED_BTS)
> return 0;
>
> + if (x86_pmu.set_period && x86_pmu.set_period(event))
> + goto update_userpage;
> +
> /*
> * If we are way outside a reasonable range then just skip forward:
> */
> @@ -1234,6 +1245,7 @@ int x86_perf_event_set_period(struct perf_event *event)
> (u64)(-left) & x86_pmu.cntval_mask);
> }
>
> +update_userpage:
> perf_event_update_userpage(event);
>
> return ret;
*groan*.... that's pretty terrible.
