On Tue, May 01, 2018 at 07:31:36AM -0700, [email protected] wrote: > From: Kan Liang <[email protected]> > > 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 > > Reported-by: Andi Kleen <[email protected]> > Signed-off-by: Kan Liang <[email protected]> > --- > > Changes since V4: > - Add WARN_ON when failing to alloc an array for leaders > - Add comments to explain why it has to go through the whole group
Acked-by: Jiri Olsa <[email protected]> thanks, jirka
