perf x86/topdown: Don't move topdown metric events in group
authorDapeng Mi <dapeng1.mi@linux.intel.com>
Fri, 13 Sep 2024 08:47:09 +0000 (08:47 +0000)
committerNamhyung Kim <namhyung@kernel.org>
Mon, 30 Sep 2024 22:23:44 +0000 (15:23 -0700)
commit3b5edc0421e2598a0ae7f0adcd592017f37e3cdf
tree264c7ac7df76dd1b571ae683c5604e34380b7c5b
parent1e53e9d1787babb1544eaec7c7fdcb78a4a20a13
perf x86/topdown: Don't move topdown metric events in group

when running below perf command, we say error is reported.

perf record -e "{slots,instructions,topdown-retiring}:S" -vv -C0 sleep 1

------------------------------------------------------------
perf_event_attr:
  type                             4 (cpu)
  size                             168
  config                           0x400 (slots)
  sample_type                      IP|TID|TIME|READ|CPU|PERIOD|IDENTIFIER
  read_format                      ID|GROUP|LOST
  disabled                         1
  sample_id_all                    1
  exclude_guest                    1
------------------------------------------------------------
sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
------------------------------------------------------------
perf_event_attr:
  type                             4 (cpu)
  size                             168
  config                           0x8000 (topdown-retiring)
  { sample_period, sample_freq }   4000
  sample_type                      IP|TID|TIME|READ|CPU|PERIOD|IDENTIFIER
  read_format                      ID|GROUP|LOST
  freq                             1
  sample_id_all                    1
  exclude_guest                    1
------------------------------------------------------------
sys_perf_event_open: pid -1  cpu 0  group_fd 5  flags 0x8
sys_perf_event_open failed, error -22

Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for
event (topdown-retiring).

The reason of error is that the events are regrouped and
topdown-retiring event is moved to closely after the slots event and
topdown-retiring event needs to do the sampling, but Intel PMU driver
doesn't support to sample topdown metrics events.

For topdown metrics events, it just requires to be in a group which has
slots event as leader. It doesn't require topdown metrics event must be
closely after slots event. Thus it's a overkill to move topdown metrics
event closely after slots event in events regrouping and furtherly cause
the above issue.

Thus don't move topdown metrics events forward if they are already in a
group.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20240913084712.13861-4-dapeng1.mi@linux.intel.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
tools/perf/arch/x86/util/evlist.c