From: Kan Liang Date: Tue, 1 Oct 2024 02:14:31 +0000 (-0700) Subject: perf jevents: Don't stop at the first matched pmu when searching a events table X-Git-Tag: v6.13-rc1~68^2~199 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=8d7f85e323ea402005fa83ddbdf5d00292d77098;p=linux-block.git perf jevents: Don't stop at the first matched pmu when searching a events table The "perf all PMU test" fails on a Coffee Lake machine. The failure is caused by the below change in the commit e2641db83f18 ("perf vendor events: Add/update skylake events/metrics"). + { + "BriefDescription": "This 48-bit fixed counter counts the UCLK cycles", + "Counter": "FIXED", + "EventCode": "0xff", + "EventName": "UNC_CLOCK.SOCKET", + "PerPkg": "1", + "PublicDescription": "This 48-bit fixed counter counts the UCLK cycles.", + "Unit": "cbox_0" } The other cbox events have the unit name "CBOX", while the fixed counter has a unit name "cbox_0". So the events_table will maintain separate entries for cbox and cbox_0. The perf_pmus__print_pmu_events() calculates the total number of events, allocate an aliases buffer, store all the events into the buffer, sort, and print all the aliases one by one. The problem is that the calculated total number of events doesn't match the stored events in the aliases buffer. The perf_pmu__num_events() is used to calculate the number of events. It invokes the pmu_events_table__num_events() to go through the entire events_table to find all events. Because of the pmu_uncore_alias_match(), the suffix of uncore PMU will be ignored. So the events for cbox and cbox_0 are all counted. When storing events into the aliases buffer, the perf_pmu__for_each_event() only process the events for cbox. Since a bigger buffer was allocated, the last entry are all 0. When printing all the aliases, null will be outputted, and trigger the failure. The mismatch was introduced from the commit e3edd6cf6399 ("perf pmu-events: Reduce processed events by passing PMU"). The pmu_events_table__for_each_event() stops immediately once a pmu is set. But for uncore, especially this case, the method is wrong and mismatch what perf does in the perf_pmu__num_events(). With the patch, $ perf list pmu | grep -A 1 clock.socket unc_clock.socket [This 48-bit fixed counter counts the UCLK cycles. Unit: uncore_cbox_0 $ perf test "perf all PMU test" 107: perf all PMU test : Ok Reported-by: kernel test robot Closes: https://lore.kernel.org/all/202407101021.2c8baddb-oliver.sang@intel.com/ Fixes: e3edd6cf6399 ("perf pmu-events: Reduce processed events by passing PMU") Signed-off-by: Kan Liang Reviewed-by: Ian Rogers Cc: Sandipan Das Cc: Benjamin Gray Cc: Xu Yang Cc: John Garry Link: https://lore.kernel.org/r/20241001021431.814811-1-irogers@google.com Signed-off-by: Namhyung Kim --- diff --git a/tools/perf/pmu-events/empty-pmu-events.c b/tools/perf/pmu-events/empty-pmu-events.c index c592079982fb..873e9fb2041f 100644 --- a/tools/perf/pmu-events/empty-pmu-events.c +++ b/tools/perf/pmu-events/empty-pmu-events.c @@ -380,7 +380,7 @@ int pmu_events_table__for_each_event(const struct pmu_events_table *table, continue; ret = pmu_events_table__for_each_event_pmu(table, table_pmu, fn, data); - if (pmu || ret) + if (ret) return ret; } return 0; diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py index bb0a5d92df4a..d46a22fb5573 100755 --- a/tools/perf/pmu-events/jevents.py +++ b/tools/perf/pmu-events/jevents.py @@ -930,7 +930,7 @@ int pmu_events_table__for_each_event(const struct pmu_events_table *table, continue; ret = pmu_events_table__for_each_event_pmu(table, table_pmu, fn, data); - if (pmu || ret) + if (ret) return ret; } return 0;