6.6-stable review patch. If anyone has any objections, please let me know.
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From: Luo Gengkun luogengkun@huaweicloud.com
[ Upstream commit 1a97fea9db9e9b9c4839d4232dde9f505ff5b4cc ]
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 <not supported> cycles <not supported> instructions <not supported> branches <not supported> 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 luogengkun@huaweicloud.com Signed-off-by: Ingo Molnar mingo@kernel.org Reviewed-by: Kan Liang kan.liang@linux.intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@redhat.com Cc: Mark Rutland mark.rutland@arm.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Ravi Bangoria ravi.bangoria@amd.com Link: https://lore.kernel.org/r/20250423064724.3716211-1-luogengkun@huaweicloud.co... Signed-off-by: Sasha Levin sashal@kernel.org --- 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 1458ccaa6a057..ad63bd408cd90 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -623,7 +623,7 @@ int x86_pmu_hw_config(struct perf_event *event) if (event->attr.type == event->pmu->type) event->hw.config |= event->attr.config & X86_RAW_EVENT_MASK;
- 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)