From patchwork Fri Jan 13 16:03:47 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 91461 Delivered-To: patch@linaro.org Received: by 10.140.20.99 with SMTP id 90csp258887qgi; Fri, 13 Jan 2017 08:04:55 -0800 (PST) X-Received: by 10.99.97.196 with SMTP id v187mr24589274pgb.175.1484323494912; Fri, 13 Jan 2017 08:04:54 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id b31si13116727pli.65.2017.01.13.08.04.54; Fri, 13 Jan 2017 08:04:54 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752310AbdAMQEe (ORCPT + 25 others); Fri, 13 Jan 2017 11:04:34 -0500 Received: from foss.arm.com ([217.140.101.70]:49242 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751773AbdAMQEN (ORCPT ); Fri, 13 Jan 2017 11:04:13 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4E8BC1610; Fri, 13 Jan 2017 08:04:12 -0800 (PST) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 22BE03F5B6; Fri, 13 Jan 2017 08:04:12 -0800 (PST) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 08DA81AE3838; Fri, 13 Jan 2017 16:04:11 +0000 (GMT) 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: [RFC PATCH v2 08/10] perf/core: Add PERF_AUX_FLAG_COLLISION to report colliding samples Date: Fri, 13 Jan 2017 16:03:47 +0000 Message-Id: <1484323429-15231-9-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1484323429-15231-1-git-send-email-will.deacon@arm.com> References: <1484323429-15231-1-git-send-email-will.deacon@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk 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(+) -- 2.1.4 diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index c66a485a24ac..68a4e542968e 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 0x03 /* sample collided with another */ #define PERF_FLAG_FD_NO_GROUP (1UL << 0) #define PERF_FLAG_FD_OUTPUT (1UL << 1)