Re: [PATCH 6/8] perf/amd/ibs: Add pmu specific minimum period

[Namhyung Kim <namhyung@kernel.org>]

On Tue, Oct 08, 2024 at 11:16:43AM +0530, Ravi Bangoria wrote:
> >> @@ -295,10 +296,14 @@ static int perf_ibs_init(struct perf_event *event)
> >>  			/* raw max_cnt may not be set */
> >>  			return -EINVAL;
> >>  
> >> -		/* Silently mask off lower nibble. IBS hw mandates it. */
> >> -		hwc->sample_period &= ~0x0FULL;
> >> -		if (!hwc->sample_period)
> >> -			hwc->sample_period = 0x10;
> >> +		if (event->attr.freq) {
> >> +			hwc->sample_period = perf_ibs->min_period;
> >> +		} else {
> >> +			/* Silently mask off lower nibble. IBS hw mandates it. */
> >> +			hwc->sample_period &= ~0x0FULL;
> >> +			if (hwc->sample_period < perf_ibs->min_period)
> >> +				return -EINVAL;
> > 
> > Maybe it needs to check perf_ibs->max_period as well.
> 
> We do allow event with sample_period > pmu->max_period and handle it with
> "period_left" logic.

Oh, ok then.

Thanks,
Namhyung