linux-kernel - [PATCH] perf tools: fix guest mode monitoring on AMD

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Message-ID: <20120227173351.GA6945@quad>
Date:	Mon, 27 Feb 2012 18:33:51 +0100
From:	Stephane Eranian <eranian@...gle.com>
To:	linux-kernel@...r.kernel.org
Cc:	acme@...hat.com, robert.richter@....com, peterz@...radead.org,
	mingo@...e.hu, joro@...tes.org, gleb@...hat.com
Subject: [PATCH] perf tools: fix guest mode monitoring on AMD

Commit:

1aed267 perf kvm: Do guest-only counting by default
 
introduced a bug on AMD systems whereby simple commands:

$ perf stat ls
Performance counter stats for 'ls':
                 0 cycles                    #    0.000 GHz                    
       0.003704596 seconds time elapsed

would not count anything anymore. Same results for perf record.

I tracked it down to guest mode exclusion being enabled
by default leading to attr->exclude_guest = 1. When
not operating under any sort of virtualization, this
causes the PMU not to count anything.

The fix disables guest exclusion by default.

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

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 8109a90..c1017b3 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -6,7 +6,7 @@
  * XXX We need to find a better place for these things...
  */
 bool perf_host  = true;
-bool perf_guest = false;
+bool perf_guest = true;
 
 void event_attr_init(struct perf_event_attr *attr)
 {
--
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