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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 9A787C4743D for ; Wed, 9 Jun 2021 01:40:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7503561182 for ; Wed, 9 Jun 2021 01:40:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232109AbhFIBmX (ORCPT ); Tue, 8 Jun 2021 21:42:23 -0400 Received: from mail-pj1-f53.google.com ([209.85.216.53]:34720 "EHLO mail-pj1-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231344AbhFIBmV (ORCPT ); Tue, 8 Jun 2021 21:42:21 -0400 Received: by mail-pj1-f53.google.com with SMTP id g6-20020a17090adac6b029015d1a9a6f1aso2730092pjx.1 for ; Tue, 08 Jun 2021 18:40:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=/d3k4uICSgLjCjjIICNIctgXwaLJ2Iz2BJO+iXE+CTE=; b=Ce1GhVArmiYuuqT3j94UWVmFQjeZPH3AVVC2vYIteA7rQdnD0WFRDvMmtGayLw+riE Sp6so76C+tLWPyEOllGZzFeMuO3ooazJwBFesKhcWXaWAfwVPx1hmzILRlRt1Kbf648j ZhCkC7sb07qz2RjQcnXgzD11+7EvDvyxfJaFQeZNDo5K9zLTfAIRovvm9SqucfB8y8Pg aZ0mEqBWkPv4puVReUYxXzc49m9jaEUKPj2DAUr4oe/hRbmaeBMeyHQZ7yAx9kaHGeFh 1CBxvjDOrMiKF6MaC0CW4475LMcDvZp2k0ew8w/rkX0KgiJgmb916EC+3X1yjlMAPRfu h3QQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=/d3k4uICSgLjCjjIICNIctgXwaLJ2Iz2BJO+iXE+CTE=; b=GJetSkgywzOdUTb7yvdMy/hODPEk6H7ot4Z2ZX05qjF8rlUdffV2lThY6BYXZ05pj7 xSTLXw0mnmNoPrzoWYk+0uryPwzVtOrdbd5adGC4ugC4JcEMaP1MjUM7A7rdlwMOrYs6 8tkKf26683z3n5gavdDG+Lv9agL4CFkngxJUyEORpYov7PZVx8XyYXfMqt/joaQ3ifoJ yGegScJn1HRwIvLZfDanMzIPfUAFCPVJW+Tc14bqJs5bcNnHlLIwXWjsLzQJt8p0sDyo 5XVjfnVc/3waes8smu6Er9OS4AI+055LJYGUJisMvyGUfHxaDOXlmwpKWe4viKLipRly 4/kA== X-Gm-Message-State: AOAM532trFOWb827V8YE5FJy81lJ0F5+nXsrhnwIZnXX1ZkCSa5QVH0V q3wsZh/UHixUwDRFielhERnTxQ== X-Google-Smtp-Source: ABdhPJy0fGqUCQQPXLN28cPcP97FKbCAmwU7xD+S4UOlHjhmhegG8QJK9GpXyIrEx+rq3flbIZuqvg== X-Received: by 2002:a17:90a:a393:: with SMTP id x19mr238868pjp.1.1623202755591; Tue, 08 Jun 2021 18:39:15 -0700 (PDT) Received: from leoy-ThinkPad-X240s (ec2-18-167-84-74.ap-east-1.compute.amazonaws.com. [18.167.84.74]) by smtp.gmail.com with ESMTPSA id f17sm12272157pgm.37.2021.06.08.18.39.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Jun 2021 18:39:15 -0700 (PDT) Date: Wed, 9 Jun 2021 09:39:09 +0800 From: Leo Yan To: Mathieu Poirier Cc: Arnaldo Carvalho de Melo , Suzuki K Poulose , Mike Leach , Alexander Shishkin , John Garry , Will Deacon , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Namhyung Kim , Daniel Kiss , Denis Nikitin , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH v1 1/3] coresight: etm-perf: Correct buffer syncing for snapshot Message-ID: <20210609013909.GE4640@leoy-ThinkPad-X240s> References: <20210528161552.654907-1-leo.yan@linaro.org> <20210528161552.654907-2-leo.yan@linaro.org> <20210608214149.GA331611@p14s> <20210609013555.GD4640@leoy-ThinkPad-X240s> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210609013555.GD4640@leoy-ThinkPad-X240s> Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Wed, Jun 09, 2021 at 09:35:55AM +0800, Leo Yan wrote: [...] > > The problem with this approach is that if the AUX buffer is 4MB and the CS > > buffer is 1MB then we only record 1MB, but because of N:1 topologies we may not > > be able to do better. I haven't looked at the code yet, something I will do > > tomorrow. > > Yes, the fixing in this patch copies the trace data is limited by the > CoreSight bounce buffer length. So if CoreSight buffer length is > 1MiB, then we have no chance to allocate 4MiB for AUX buffer. Sorry for typo, just correct: if CoreSight buffer length is 1MiB, then we have no chance to *copy* 4MiB trace data for AUX buffer.