From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755649AbdDFQSS (ORCPT ); Thu, 6 Apr 2017 12:18:18 -0400 Received: from foss.arm.com ([217.140.101.70]:45446 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755318AbdDFQSC (ORCPT ); Thu, 6 Apr 2017 12:18:02 -0400 From: Will Deacon 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 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 Message-Id: <1491495496-1524-5-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1491495496-1524-1-git-send-email-will.deacon@arm.com> References: <1491495496-1524-1-git-send-email-will.deacon@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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