From: Luo Gengkun Date: Wed, 23 Apr 2025 06:47:24 +0000 (+0000) Subject: perf/x86: Fix non-sampling (counting) events on certain x86 platforms X-Git-Tag: v6.15-rc4~5^2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=1a97fea9db9e9b9c4839d4232dde9f505ff5b4cc;p=linux-2.6-block.git perf/x86: Fix non-sampling (counting) events on certain x86 platforms Perf doesn't work at perf stat for hardware events on certain x86 platforms: $perf stat -- sleep 1 Performance counter stats for 'sleep 1': 16.44 msec task-clock # 0.016 CPUs utilized 2 context-switches # 121.691 /sec 0 cpu-migrations # 0.000 /sec 54 page-faults # 3.286 K/sec cycles instructions branches branch-misses The reason is that the check in x86_pmu_hw_config() for sampling events is unexpectedly applied to counting events as well. It should only impact x86 platforms with limit_period used for non-PEBS events. For Intel platforms, it should only impact some older platforms, e.g., HSW, BDW and NHM. Fixes: 88ec7eedbbd2 ("perf/x86: Fix low freqency setting issue") Signed-off-by: Luo Gengkun Signed-off-by: Ingo Molnar Reviewed-by: Kan Liang Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Link: https://lore.kernel.org/r/20250423064724.3716211-1-luogengkun@huaweicloud.com --- diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 6866cc5acb0b..3a4f031d2f44 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -629,7 +629,7 @@ 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.freq && x86_pmu.limit_period) { + if (is_sampling_event(event) && !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)