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
Committer testing:
[root@seventh ~]# perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}'
WARNING: grouped events cpus do not match, disabling group:
anon group { power/energy-cores/, cycles }
anon group { instructions, power/energy-cores/ }
^C
Performance counter stats for 'system wide':
12.62 Joules power/energy-cores/
106,920,637 cycles
80,228,899 instructions # 0.75 insn per cycle
12.62 Joules power/energy-cores/
14.514476987 seconds time elapsed
[root@seventh ~]#
But if we put compatible events in each group it works:
[root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' -a sleep 2
Performance counter stats for 'system wide':
1.95 Joules power/energy-cores/
0.92 Joules power/energy-ram/
29,305,715 instructions # 1.03 insn per cycle
28,423,338 cycles
2.001438142 seconds time elapsed
[root@seventh ~]#
This needs improvement tho:
[root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' sleep 2
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (power/energy-cores/).
/bin/dmesg | grep -i perf may provide additional information.
[root@seventh ~]#
We need to emit a better message, one stating that the power/ events
can't be used for a specific workload, instead it is per-cpu or system
wide.
Fixes: 6a4bb04caa ("perf tools: Enable grouping logic for parsed events")
Co-developed-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200602101736.GE1112120@krava
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
a9a1790247