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

[Ravi Bangoria]

>> @@ -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.

Thanks,
Ravi