From 88ec7eedbbd21cad38707620ad6c48a4e9a87c18 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Fri, 17 Jan 2025 07:19:11 -0800 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar Reviewed-by: Ravi Bangoria Cc: Peter Zijlstra 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/ --- 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 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)