Commit 3b5edc04 authored by Dapeng Mi's avatar Dapeng Mi Committed by Namhyung Kim
Browse files

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: default avatarKan Liang <kan.liang@linux.intel.com>
Signed-off-by: default avatarDapeng 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: default avatarNamhyung Kim <namhyung@kernel.org>
parent 1e53e9d1
Loading
Loading
Loading
Loading
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Please to comment