linux-kernel - [PATCH] perf/x86/intel: allow PEBS multi-entry in watermark mode

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Message-Id: <20190514003400.224340-1-eranian@google.com>
Date:   Mon, 13 May 2019 17:34:00 -0700
From:   Stephane Eranian <eranian@...gle.com>
To:     linux-kernel@...r.kernel.org
Cc:     peterz@...radead.org, ak@...ux.intel.com, kan.liang@...el.com,
        mingo@...e.hu, jolsa@...hat.com, vincent.weaver@...ne.edu
Subject: [PATCH] perf/x86/intel: allow PEBS multi-entry in watermark mode

This patch fixes an issue introduced with:

   583feb08e7f7 ("perf/x86/intel: Fix handling of wakeup_events for multi-entry PEBS")

The original patch prevented using multi-entry PEBS when wakeup_events != 0.
However given that wakeup_events is part of a union with wakeup_watermark, it
means that in watermark mode, PEBS multi-entry is also disabled which is not the
intent. This patch fixes this by checking is watermark mode is enabled.

Signed-off-by: Stephane Eranian <eranian@...gle.com>
Change-Id: I8362bbcf9035c860b64b4c2e8faf310ebd74c234
---
 arch/x86/events/intel/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 416233f92b3c..613fabba2c99 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3280,7 +3280,7 @@ static int intel_pmu_hw_config(struct perf_event *event)
 		return ret;
 
 	if (event->attr.precise_ip) {
-		if (!(event->attr.freq || event->attr.wakeup_events)) {
+		if (!(event->attr.freq || (event->attr.wakeup_events && !event->attr.watermark))) {
 			event->hw.flags |= PERF_X86_EVENT_AUTO_RELOAD;
 			if (!(event->attr.sample_type &
 			      ~intel_pmu_large_pebs_flags(event)))