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

[Namhyung Kim <namhyung@kernel.org>]

On Tue, Jun 2, 2020 at 1:21 AM Ian Rogers <irogers@google.com> wrote:
>
> On Mon, Jun 1, 2020 at 1:20 AM Jiri Olsa <jolsa@redhat.com> 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.

Allowed cpus?

Thanks
Namhyung