[tip: perf/urgent] perf/x86/intel: Fix GRT PEBS load/store direction for latency events, to fix sample classification

[tip-bot2 for Dapeng Mi]

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     89dc568e8c0be60e05e5fcd0b528c79077d7b84b
Gitweb:        https://git.kernel.org/tip/89dc568e8c0be60e05e5fcd0b528c79077d7b84b
Author:        Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
AuthorDate:    Thu, 17 Sep 2026 09:52:23 +08:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 22 Sep 2026 11:17:00 +02:00

perf/x86/intel: Fix GRT PEBS load/store direction for latency events, to fix sample classification

On Gracemont, intel_grt_pebs_event_constraints[] applies LAT_CONSTRAINT
constraints to MEM_UOPS_RETIRED.{LOAD,STORE}_LATENCY, but does not set
explicit LOAD/STORE flags for those events.

The PEBS latency path (pebs_latency_data(), via __grt_latency_data())
uses the event flags to determine memory operation direction. Without an
explicit STORE flag, samples from MEM_UOPS_RETIRED.STORE_LATENCY can be
misclassified as LOADs.

Set explicit LOAD/STORE flags in intel_grt_pebs_event_constraints[] for:

- MEM_UOPS_RETIRED.LOAD_LATENCY
- MEM_UOPS_RETIRED.STORE_LATENCY

Also update __grt_latency_data() to explicitly interpret these flags when
assigning the sampled memory operation direction.

This fixes incorrect STORE sample classification.

Fixes: 39a41278f041 ("perf/x86/intel: Fix PEBS memory access info encoding for ADL")
Signed-off-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v7.2+
Link: https://patch.msgid.link/20260917015234.981153-2-dapeng1.mi@xxxxxxxxxxxxxxx
---
 arch/x86/events/intel/ds.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index b98029b..fff98f4 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -455,6 +455,7 @@ static inline void pebs_set_tlb_lock(u64 *val, bool tlb, bool lock)
 static u64 __grt_latency_data(struct perf_event *event, u64 status,
 			       u8 dse, bool tlb, bool lock, bool blk)
 {
+	union perf_mem_data_src src;
 	u64 val;
 
 	WARN_ON_ONCE(is_hybrid() &&
@@ -470,7 +471,16 @@ static u64 __grt_latency_data(struct perf_event *event, u64 status,
 	else
 		val |= P(BLK, NA);
 
-	return val;
+	src.val = val;
+
+	if (event->hw.flags &
+	    (PERF_X86_EVENT_PEBS_LDLAT | PERF_X86_EVENT_PEBS_LD_HSW))
+		src.mem_op = P(OP, LOAD);
+	if (event->hw.flags &
+	    (PERF_X86_EVENT_PEBS_STLAT | PERF_X86_EVENT_PEBS_ST_HSW))
+		src.mem_op = P(OP, STORE);
+
+	return src.val;
 }
 
 u64 grt_latency_data(struct perf_event *event, u64 status)
@@ -1291,8 +1301,8 @@ struct event_constraint intel_glm_pebs_event_constraints[] = {
 
 struct event_constraint intel_grt_pebs_event_constraints[] = {
 	/* Allow all events as PEBS with no flags */
-	INTEL_HYBRID_LAT_CONSTRAINT(0x5d0, 0x3),
-	INTEL_HYBRID_LAT_CONSTRAINT(0x6d0, 0x3f),
+	INTEL_HYBRID_LDLAT_CONSTRAINT(0x5d0, 0x3),
+	INTEL_HYBRID_STLAT_CONSTRAINT(0x6d0, 0x3f),
 	EVENT_CONSTRAINT_END
 };