Messages in this thread | | | Subject | Re: [V2 PATCH] perf parse-events: Specially handle uncore event alias in small groups | From | "Liang, Kan" <> | Date | Wed, 25 Apr 2018 11:28:22 -0400 |
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On 4/25/2018 10:59 AM, Jiri Olsa wrote: > 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) >
Yes, there is a bug if leader and member have the same event name. I will fix it in V3. Thanks for the test.
Thanks, Kan
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