From: Will Deacon <will.deacon@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: marc.zyngier@arm.com, mark.rutland@arm.com, kim.phillips@arm.com,
alex.bennee@linaro.org, christoffer.dall@linaro.org,
tglx@linutronix.de, peterz@infradead.org,
alexander.shishkin@linux.intel.com, robh@kernel.org,
suzuki.poulose@arm.com, pawel.moll@arm.com,
mathieu.poirier@linaro.org, mingo@redhat.com,
linux-kernel@vger.kernel.org, Will Deacon <will.deacon@arm.com>
Subject: [PATCH v2 4/6] perf/core: Add PERF_AUX_FLAG_COLLISION to report colliding samples
Date: Thu, 6 Apr 2017 17:18:14 +0100 [thread overview]
Message-ID: <1491495496-1524-5-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1491495496-1524-1-git-send-email-will.deacon@arm.com>
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.
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
include/uapi/linux/perf_event.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index c66a485a24ac..f4e3a21cade5 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -885,6 +885,7 @@ 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_COLLISION 0x08 /* sample collided with another */
#define PERF_FLAG_FD_NO_GROUP (1UL << 0)
#define PERF_FLAG_FD_OUTPUT (1UL << 1)
--
2.1.4
next prev parent reply other threads:[~2017-04-06 16:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-06 16:18 [PATCH v2 0/6] Add support for the ARMv8.2 Statistical Profiling Extension Will Deacon
2017-04-06 16:18 ` [PATCH v2 1/6] perf/core: Keep AUX flags in the output handle Will Deacon
2017-04-06 16:18 ` [PATCH v2 2/6] genirq: export irq_get_percpu_devid_partition to modules Will Deacon
2017-04-06 16:18 ` [PATCH v2 3/6] perf/core: Export AUX buffer helpers " Will Deacon
2017-04-06 16:18 ` Will Deacon [this message]
2017-04-06 16:18 ` [PATCH v2 5/6] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Will Deacon
2017-04-06 18:33 ` Kim Phillips
2017-04-06 18:45 ` Mark Rutland
2017-04-07 10:52 ` Kim Phillips
2017-04-07 11:31 ` Mark Rutland
2017-04-07 15:22 ` Kim Phillips
2017-04-06 16:18 ` [PATCH v2 6/6] dt-bindings: Document devicetree binding for ARM SPE Will Deacon
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