From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EA30C433E0 for ; Wed, 27 Jan 2021 14:16:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E138F207B7 for ; Wed, 27 Jan 2021 14:16:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233925AbhA0OPf (ORCPT ); Wed, 27 Jan 2021 09:15:35 -0500 Received: from foss.arm.com ([217.140.110.172]:48390 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232605AbhA0ONN (ORCPT ); Wed, 27 Jan 2021 09:13:13 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8BA471FB; Wed, 27 Jan 2021 06:12:23 -0800 (PST) Received: from [10.57.40.145] (unknown [10.57.40.145]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B8C853F68F; Wed, 27 Jan 2021 06:12:21 -0800 (PST) Subject: Re: [PATCH V3 14/14] coresight: etm-perf: Add support for trace buffer format To: Peter Zijlstra , Anshuman Khandual Cc: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, mathieu.poirier@linaro.org, mike.leach@linaro.org, lcherian@marvell.com, linux-kernel@vger.kernel.org, Leo Yan References: <1611737738-1493-1-git-send-email-anshuman.khandual@arm.com> <1611737738-1493-15-git-send-email-anshuman.khandual@arm.com> From: Suzuki K Poulose Message-ID: Date: Wed, 27 Jan 2021 14:12:15 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter On 1/27/21 12:54 PM, Peter Zijlstra wrote: > On Wed, Jan 27, 2021 at 02:25:38PM +0530, Anshuman Khandual wrote: > >> It is possible to have a >> perf session where some events end up collecting the trace >> in TMC-ETR while the others in TRBE. Thus we need a way >> to identify the type of the trace for each AUX record. > >> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h >> index 9a5ca45..169e6b3 100644 >> --- a/include/uapi/linux/perf_event.h >> +++ b/include/uapi/linux/perf_event.h >> @@ -1111,6 +1111,10 @@ enum perf_callchain_context { >> #define PERF_AUX_FLAG_COLLISION 0x08 /* sample collided with another */ >> #define PERF_AUX_FLAG_PMU_FORMAT_TYPE_MASK 0xff00 /* PMU specific trace format type */ >> >> +/* CoreSight PMU AUX buffer formats */ >> +#define PERF_AUX_FLAG_CORESIGHT_FORMAT_CORESIGHT 0x0000 /* Default for backward compatibility */ >> +#define PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW 0x0100 /* Raw format of the source */ > > Would CORESIGHT_FORMAT_ETR / CORESIGHT_FORMAT_TRBE be better names? > Not really. The format used by the ETR is CORESIGHT frame formatting. And there are other sinks that uses the formatting. e.g, TMC-ETB (a sink with internal memory), TMC-ETF (trace fifo with internal memory). So it is really not tied to ETR. As for TRBE, it simply pumps the data thrown at it to the memory. As such calling it TRBE format would be confusing as the format of the buffer is really Raw trace thrown at it. This can be inferred from the ETM/ETE looking at the ID registers, which the userspace perf already captures in the perf.data. So the decoder perf can look at the perf.data and the AUX records to interpret the buffer correctly. Suzuki