Re: [PATCHv2] perf stat: Ensure group is defined on top of the same cpu mask

From: Jiri Olsa
Date: Tue Jun 02 2020 - 04:16:05 EST


On Tue, Jun 02, 2020 at 11:47:19AM +0900, Namhyung Kim wrote:
> On Tue, Jun 2, 2020 at 1:21 AM Ian Rogers <irogers@xxxxxxxxxx> wrote:
> >
> > On Mon, Jun 1, 2020 at 1:20 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> > >
> > > Jin Yao reported the issue (and posted first versions of this change)
> > > with groups being defined over events with different cpu mask.
> > >
> > > This causes assert aborts in get_group_fd, like:
> > >
> > > # perf stat -M "C2_Pkg_Residency" -a -- sleep 1
> > > perf: util/evsel.c:1464: get_group_fd: Assertion `!(fd == -1)' failed.
> > > Aborted
> > >
> > > All the events in the group have to be defined over the same
> > > cpus so the group_fd can be found for every leader/member pair.
> > >
> > > Adding check to ensure this condition is met and removing the
> > > group (with warning) if we detect mixed cpus, like:
> > >
> > > $ sudo perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}'
> > > WARNING: event cpu maps do not match, disabling group:
> > > anon group { power/energy-cores/, cycles }
> > > anon group { instructions, power/energy-cores/ }
> > >
> > > Ian asked also for cpu maps details, it's displayed in verbose mode:
> > >
> > > $ sudo perf stat -e '{cycles,power/energy-cores/}' -v
> > > WARNING: group events cpu maps do not match, disabling group:
> > > anon group { power/energy-cores/, cycles }
> > > power/energy-cores/: 0
> > > cycles: 0-7
> > > anon group { instructions, power/energy-cores/ }
> > > instructions: 0-7
> > > power/energy-cores/: 0
> >
> > This is great! A nit, would 'grouped events cpus do not match' read
> > better? I think the cpu map is more of an internal naming convention.

ok

>
> Allowed cpus?

hum, what you mean?

jirka

>
> Thanks
> Namhyung
>