[PATCH] perf, x86: Report TSX transaction abort cost as weight

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

[This requires one patch to the user space code to revert
afab87b91f3f331d so that --weight works again without perf mem.
The patch has been submitted separately]

Use the existing weight reporting facility to report the transaction
abort cost, that is the number of cycles wasted in aborts.
Haswell reports this in the PEBS record.

This was in fact the original user for weight.

This is a very useful sort key to concentrate on the most
costly aborts and a good metric for TSX tuning.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 3065c57..8959cc7 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -838,6 +838,12 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
 		x86_pmu.intel_cap.pebs_format >= 1)
 		data.addr = pebs->dla;
 
+	if ((event->attr.sample_type & PERF_SAMPLE_WEIGHT) &&
+	    !fll &&
+	    (x86_pmu.intel_cap.pebs_format >= 2) &&
+	    pebs_hsw->tsx_tuning)
+		data.weight = pebs_hsw->tsx_tuning & 0xffffffff;
+
 	if (has_branch_stack(event))
 		data.br_stack = &cpuc->lbr_stack;
 
-- 
1.8.1.4

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