diff options
| author | Kan Liang <kan.liang@linux.intel.com> | 2025-01-17 18:19:11 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-02-25 16:54:14 +0300 |
| commit | 88ec7eedbbd21cad38707620ad6c48a4e9a87c18 (patch) | |
| tree | 3db1ada398a43fbf771ca0febf20e0d1c2c48564 | |
| parent | bddf10d26e6e5114e7415a0e442ec6f51a559468 (diff) | |
| download | linux-88ec7eedbbd21cad38707620ad6c48a4e9a87c18.tar.xz | |
perf/x86: Fix low freqency setting issue
Perf doesn't work at low frequencies:
$ perf record -e cpu_core/instructions/ppp -F 120
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument)
for event (cpu_core/instructions/ppp).
"dmesg | grep -i perf" may provide additional information.
The limit_period() check avoids a low sampling period on a counter. It
doesn't intend to limit the frequency.
The check in the x86_pmu_hw_config() should be limited to non-freq mode.
The attr.sample_period and attr.sample_freq are union. The
attr.sample_period should not be used to indicate the frequency mode.
Fixes: c46e665f0377 ("perf/x86: Add INST_RETIRED.ALL workarounds")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250117151913.3043942-1-kan.liang@linux.intel.com
Closes: https://lore.kernel.org/lkml/20250115154949.3147-1-ravi.bangoria@amd.com/
| -rw-r--r-- | arch/x86/events/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 8f218ac0d445..2092d615333d 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -628,7 +628,7 @@ int x86_pmu_hw_config(struct perf_event *event) if (event->attr.type == event->pmu->type) event->hw.config |= x86_pmu_get_event_config(event); - if (event->attr.sample_period && x86_pmu.limit_period) { + if (!event->attr.freq && x86_pmu.limit_period) { s64 left = event->attr.sample_period; x86_pmu.limit_period(event, &left); if (left > event->attr.sample_period) |