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SubjectRe: [V2 PATCH] perf parse-events: Specially handle uncore event alias in small groups
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:

[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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