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SubjectRe: [V2 PATCH] perf parse-events: Specially handle uncore event alias in small groups
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On 4/25/2018 10:23 AM, Jiri Olsa wrote:
> On Wed, Apr 25, 2018 at 06:50:18AM -0700, kan.liang@linux.intel.com wrote:
>> From: Kan Liang <kan.liang@linux.intel.com>
>>
>> Perf stat doesn't count the uncore event aliases from the same uncore
>> block in a group, for example:
>>
>> perf stat -e '{unc_m_cas_count.all,unc_m_clockticks}' -a -I 1000
>> # time counts unit events
>> 1.000447342 <not counted> unc_m_cas_count.all
>> 1.000447342 <not counted> unc_m_clockticks
>> 2.000740654 <not counted> unc_m_cas_count.all
>> 2.000740654 <not counted> unc_m_clockticks
>>
>> The output is very misleading. It gives a wrong impression that the
>> uncore event doesn't work.
>>
>> An uncore block could be composed by several PMUs. An uncore event alias
>> is a joint name which means the same event runs on all PMUs of a block.
>> Perf doesn't support mixed events from different PMUs in the same group.
>> It is wrong to put uncore event aliases in a big group.
>>
>> The right way is to split the big group into multiple small groups which
>> only include the events from the same PMU.
>> Only uncore event aliases from the same uncore block should be specially
>> handled here. It doesn't make sense to mix the uncore events with other
>> uncore events from different blocks or even core events in a group.
>>
>> With the patch:
>> # time counts unit events
>> 1.001557653 140,833 unc_m_cas_count.all
>> 1.001557653 1,330,231,332 unc_m_clockticks
>> 2.002709483 85,007 unc_m_cas_count.all
>> 2.002709483 1,429,494,563 unc_m_clockticks
>
> hum, I still can see the original behaviour even with the patch:
>

That's because the data_reads and clockticks are from different uncore
blocks. The data_reads is a IMC event. The clockticks is a CBOX event.

The patch only supports the events from the same uncore blocks in group.

Thanks,
Kan


> [jolsa@krava perf]$ sudo ./perf stat -e '{data_reads,clockticks}' -a -I 1000
> # time counts unit events
> 1.000184929 <not counted> MiB data_reads
> 1.000184929 <not supported> clockticks
> 2.000552765 <not counted> MiB data_reads
> 2.000552765 <not supported> clockticks
> 3.000846298 <not counted> MiB data_reads
> 3.000846298 <not supported> clockticks
> 4.001044852 <not counted> MiB data_reads
> 4.001044852 <not supported> clockticks
> 5.001247131 <not counted> MiB data_reads
> 5.001247131 <not supported> clockticks
> ^C 5.546917060 <not counted> MiB data_reads
> 5.546917060 <not supported> clockticks
>
>
> jirka
>

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