Linux 4.1 added the possibility of perf_event_open() returning
EBUSY if an existing exclusive event controls the PMU.
This was introduced by the following commit:
commit bed5b25ad9c8a2f5d735ef0bc746ec870c01c1b0
Author: Alexander Shishkin <alexander.shish...@linux.intel.com>
Date: Fri Jan 30 12:31:06 2015 +0200
perf: Add a pmu capability for "exclusive" events
Signed-off-by: Alexander Shishkin <alexander.shish...@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Kaixu Xia <kaixu....@linaro.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Mike Galbraith <efa...@gmx.de>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Robert Richter <r...@kernel.org>
Cc: Stephane Eranian <eran...@google.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: a...@infradead.org
Cc: adrian.hun...@intel.com
Cc: kan.li...@intel.com
Cc: markus.t.metz...@intel.com
Cc: mathieu.poir...@linaro.org
Signed-off-by: Vince Weaver <vincent.wea...@maine.edu>
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index b3cd93f..3d03786 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -2911,6 +2911,11 @@ the cgroup file descriptor in
.I pid
is not valid.
.TP
+.BR EBUSY " (since Linux 4.1)"
+.\" bed5b25ad9c8a2f5d735ef0bc746ec870c01c1b0
+Returned if another event already has exclusive
+access to the PMU.
+.TP
.B EFAULT
Returned if the
.I attr
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