linux-kernel - [tip:perf/stat] perf event, x86: Use better stalled cycles metric

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Message-ID: <tip-7y40wib8n1eqio7hjpn2dsrm@git.kernel.org>
Date:	Thu, 28 Apr 2011 06:54:56 GMT
From:	tip-bot for Ingo Molnar <mingo@...e.hu>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, acme@...hat.com, hpa@...or.com,
	mingo@...hat.com, a.p.zijlstra@...llo.nl, fweisbec@...il.com,
	tglx@...utronix.de, mingo@...e.hu
Subject: [tip:perf/stat] perf event, x86: Use better stalled cycles metric

Commit-ID:  8a850cadca0e387c87a0911a61e99fd66aeb57ec
Gitweb:     http://git.kernel.org/tip/8a850cadca0e387c87a0911a61e99fd66aeb57ec
Author:     Ingo Molnar <mingo@...e.hu>
AuthorDate: Thu, 28 Apr 2011 11:16:44 +0200
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Thu, 28 Apr 2011 08:39:33 +0200

perf event, x86: Use better stalled cycles metric

Use the UOPS_EXECUTED.*,c=1,i=1 event on Intel CPUs - it is a rather
good indicator of CPU execution stalls, more sensitive and more inclusive
than the 0xa2 resource stalls event (which does not count nearly as many
stall types).

Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Link: http://lkml.kernel.org/n/tip-7y40wib8n1eqio7hjpn2dsrm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/kernel/cpu/perf_event_intel.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 067a48b..1ea9422 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1413,8 +1413,8 @@ static __init int intel_pmu_init(void)
 		x86_pmu.enable_all = intel_pmu_nhm_enable_all;
 		x86_pmu.extra_regs = intel_nehalem_extra_regs;
 
-		/* Install the stalled-cycles event: 0xff: All reasons, 0xa2: Resource stalls */
-		intel_perfmon_event_map[PERF_COUNT_HW_STALLED_CYCLES] = 0xffa2;
+		/* Install the stalled-cycles event: UOPS_EXECUTED.CORE_ACTIVE_CYCLES,c=1,i=1 */
+		intel_perfmon_event_map[PERF_COUNT_HW_STALLED_CYCLES] = 0x1803fb1;
 
 		if (ebx & 0x40) {
 			/*
--
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