The following commit has been merged into the perf/urgent branch of tip: Commit-ID: 88ec7eedbbd21cad38707620ad6c48a4e9a87c18 Gitweb: https://git.kernel.org/tip/88ec7eedbbd21cad38707620ad6c48a4e9a87c18 Author: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> AuthorDate: Fri, 17 Jan 2025 07:19:11 -08:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 25 Feb 2025 14:54:14 +01:00 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@xxxxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Reviewed-by: Ravi Bangoria <ravi.bangoria@xxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20250117151913.3043942-1-kan.liang@xxxxxxxxxxxxxxx Closes: https://lore.kernel.org/lkml/20250115154949.3147-1-ravi.bangoria@xxxxxxx/ --- arch/x86/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 8f218ac..2092d61 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)
