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SubjectRe: [V2 PATCH] perf parse-events: Specially handle uncore event alias in small groups
On Wed, Apr 25, 2018 at 10:42:27AM -0400, Liang, Kan wrote:
>
>
> 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.

I see, found another example from same uncore blocks and it seems to work:
# perf stat -e '{cas_count_read,cas_count_write}' -a -I 1000

but I have it aborted on:
# ./perf stat -e '{cas_count_read,cas_count_write,cas_count_read}' -a -I 1000
perf: util/evsel.c:1483: get_group_fd: Assertion `!(!leader->fd)' failed.
Aborted (core dumped)

jirka

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