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authorWill Deacon <will.deacon@arm.com>2016-09-23 14:05:12 +0100
committerWill Deacon <will.deacon@arm.com>2017-10-18 12:53:31 +0100
commit085b30625e39df67d7320f22269796276c6b0c11 (patch)
tree9a894a6253b6ccd4126bb921fbdc465a3182daa0
parentbc1d202023eb66f088f736ba423bee1cf135c720 (diff)
downloadop-kernel-dev-085b30625e39df67d7320f22269796276c6b0c11.zip
op-kernel-dev-085b30625e39df67d7320f22269796276c6b0c11.tar.gz
perf/core: Add PERF_AUX_FLAG_COLLISION to report colliding samples
The ARM SPE architecture permits an implementation to ignore a sample if the sample is due to be taken whilst another sample is already being produced. In this case, it is desirable to report the collision to userspace, as they may want to lower the sample period. This patch adds a PERF_AUX_FLAG_COLLISION flag, so that such events can be relayed to userspace. Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--include/uapi/linux/perf_event.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 140ae63..7ca1b22 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -941,6 +941,7 @@ enum perf_callchain_context {
#define PERF_AUX_FLAG_TRUNCATED 0x01 /* record was truncated to fit */
#define PERF_AUX_FLAG_OVERWRITE 0x02 /* snapshot from overwrite mode */
#define PERF_AUX_FLAG_PARTIAL 0x04 /* record contains gaps */
+#define PERF_AUX_FLAG_COLLISION 0x08 /* sample collided with another */
#define PERF_FLAG_FD_NO_GROUP (1UL << 0)
#define PERF_FLAG_FD_OUTPUT (1UL << 1)
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