diff options
author | Namhyung Kim <namhyung@kernel.org> | 2025-04-09 18:02:52 -0700 |
---|---|---|
committer | Namhyung Kim <namhyung@kernel.org> | 2025-04-11 09:22:49 -0700 |
commit | 2b70702917337a8d6d07f03eed961e0119091647 (patch) | |
tree | 583a8f1a42cdc166e141770f50b6bb7e7ec0a8c6 /rust/helpers/workqueue.c | |
parent | 1293dacbbd43ab9848ac4655f6f2ba1dcc5a96ad (diff) | |
download | linux-2b70702917337a8d6d07f03eed961e0119091647.tar.gz linux-2b70702917337a8d6d07f03eed961e0119091647.tar.bz2 linux-2b70702917337a8d6d07f03eed961e0119091647.zip |
perf tools: Remove evsel__handle_error_quirks()
The evsel__handle_error_quirks() is to fixup invalid event attributes on
some architecture based on the error code. Currently it's only used for
AMD to disable precise_ip not to use IBS which has more restrictions.
But the commit c33aea446bf555ab changed call evsel__precise_ip_fallback
for any errors so there's no difference with the above function. To
make matter worse, it caused a problem with branch stack on Zen3.
The IBS doesn't support branch stack so it should use a regular core
PMU event. The default event is set precise_max and it starts with 3.
And evsel__precise_ip_fallback() tries with it and reduces the level one
by one. At last it tries with 0 but it also failed on Zen3 since the
branch stack is not supported for the cycles event.
At this point, evsel__precise_ip_fallback() restores the original
precise_ip value (3) in the hope that it can succeed with other modifier
(like exclude_kernel). Then evsel__handle_error_quirks() see it has
precise_ip != 0 and make it retry with 0. This created an infinite
loop.
Before:
$ perf record -b -vv |& grep removing
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
removing precise_ip on AMD
...
After:
$ perf record -b true
Error:
Failure to open event 'cycles:P' on PMU 'cpu' which will be removed.
Invalid event (cycles:P) in per-thread mode, enable system wide with '-a'.
Error:
Failure to open any events for recording.
Fixes: c33aea446bf555ab ("perf tools: Fix precise_ip fallback logic")
Tested-by: Chun-Tse Shao <ctshao@google.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20250410010252.402221-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'rust/helpers/workqueue.c')
0 files changed, 0 insertions, 0 deletions