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Subject[PATCH v2]: fix Haswell precise store data source encoding

This patch fixes a bug in precise_store_data_hsw() whereby
it would set the data source memory level to the wrong value.

As per the the SDM Vol 3b Table 18-41 (Layout of Data Linear
Address Information in PEBS Record), when status bit 0 is set
this is a L1 hit, otherwise this is a L1 miss.

This patch encodes the memory level according to the specification.

In V2, we added the filtering on the store events.
Only the following events produce L1 information:
* MEM_UOPS_RETIRED.STLB_MISS_STORES
* MEM_UOPS_RETIRED.LOCK_STORES
* MEM_UOPS_RETIRED.SPLIT_STORES
* MEM_UOPS_RETIRED.ALL_STORES

Signed-off-by: Stephane Eranian <eranian@google.com>

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index ae96cfa..980970c 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -108,15 +108,31 @@ static u64 precise_store_data(u64 status)
return val;
}

-static u64 precise_store_data_hsw(u64 status)
+static u64 precise_store_data_hsw(struct perf_event *event, u64 status)
{
union perf_mem_data_src dse;
+ u64 cfg = event->hw.config & INTEL_ARCH_EVENT_MASK;

dse.val = 0;
dse.mem_op = PERF_MEM_OP_STORE;
dse.mem_lvl = PERF_MEM_LVL_NA;
+
+ /*
+ * L1 info only valid for following events:
+ *
+ * MEM_UOPS_RETIRED.STLB_MISS_STORES
+ * MEM_UOPS_RETIRED.LOCK_STORES
+ * MEM_UOPS_RETIRED.SPLIT_STORES
+ * MEM_UOPS_RETIRED.ALL_STORES
+ */
+ if (cfg != 0x12d0 && cfg != 0x22d0 && cfg != 0x42d0 && cfg != 0x82d0)
+ return dse.mem_lvl;
+
if (status & 1)
- dse.mem_lvl = PERF_MEM_LVL_L1;
+ dse.mem_lvl = PERF_MEM_LVL_L1 | PERF_MEM_LVL_HIT;
+ else
+ dse.mem_lvl = PERF_MEM_LVL_L1 | PERF_MEM_LVL_MISS;
+
/* Nothing else supported. Sorry. */
return dse.val;
}
@@ -887,7 +903,7 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
data.data_src.val = load_latency_data(pebs->dse);
else if (event->hw.flags & PERF_X86_EVENT_PEBS_ST_HSW)
data.data_src.val =
- precise_store_data_hsw(pebs->dse);
+ precise_store_data_hsw(event, pebs->dse);
else
data.data_src.val = precise_store_data(pebs->dse);
}

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