linux-kernel - Re: [PATCH V2 0/5] Several fixes for group flag and counters-snapshotting

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Message-ID: <c919a36c-f343-48ce-a262-401159c5bf30@linux.intel.com>
Date: Thu, 24 Apr 2025 12:00:02 -0400
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: mingo@...hat.com, acme@...nel.org, namhyung@...nel.org,
 irogers@...gle.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 0/5] Several fixes for group flag and
 counters-snapshotting



On 2025-04-24 10:25 a.m., Peter Zijlstra wrote:
> On Thu, Apr 24, 2025 at 06:47:13AM -0700, kan.liang@...ux.intel.com wrote:
>> From: Kan Liang <kan.liang@...ux.intel.com>
>>
>> The patch series includes several fixes for the new Intel features.
>>
>> The first 4 patches are to fix the group flag issue which impacts the
>> branch counters, PEBS counters-snapshotting and ACR.
>> The V1 can be found at
>> https://lore.kernel.org/lkml/20250423221015.268949-1-kan.liang@linux.intel.com/
>>
>> The last patch is to fix an issue of counters-snapshotting.
>> The V1 can be found at
>> https://lore.kernel.org/lkml/20250204210514.4089680-1-kan.liang@linux.intel.com/
>>
>> Kan Liang (5):
>>   perf/x86/intel: Only check the group flag for X86 leader
>>   perf/x86/intel: Check the X86 leader for pebs_counter_event_group
>>   perf/x86/intel: Check the X86 leader for ACR group
>>   perf/x86: Optimize the is_x86_event
>>   perf/x86/intel/ds: Fix counter backwards of non-precise events
>>     counters-snapshotting
> 
> It didn't apply cleanly,

Sorry for it.

> but I stomped on it and pushed out new
> perf/urgent and perf/core branches that contain these patches. Hopefully
> I didn't mess it up ;-)

Something is missed in this patch 5d4d71ebc737 ("perf/x86/intel: Only
check the group flag for X86 leader")

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index a73b1ff031b2..1f72a4f77b5c 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -119,7 +119,7 @@ static inline bool check_leader_group(struct
perf_event *leader, int flags)

 static inline bool is_branch_counters_group(struct perf_event *event)
 {
-	return check_leader_group(event->group_leader, PERF_X86_EVENT_PEBS_CNTR);
+	return check_leader_group(event->group_leader,
PERF_X86_EVENT_BRANCH_COUNTERS);
 }

 static inline bool is_pebs_counter_event_group(struct perf_event *event)
@@ -1123,7 +1123,6 @@ static struct perf_pmu_format_hybrid_attr
format_attr_hybrid_##_name = {\
 	.pmu_type	= _pmu,                                         \
 }

-int is_x86_event(struct perf_event *event);
 struct pmu *x86_get_pmu(unsigned int cpu);
 extern struct x86_pmu x86_pmu __read_mostly;


Thanks,
Kan