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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 010EAC76195 for ; Thu, 18 Jul 2019 09:37:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4DFE2173E for ; Thu, 18 Jul 2019 09:37:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389453AbfGRJhX (ORCPT ); Thu, 18 Jul 2019 05:37:23 -0400 Received: from foss.arm.com ([217.140.110.172]:56222 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726665AbfGRJhX (ORCPT ); Thu, 18 Jul 2019 05:37:23 -0400 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 A992D28; Thu, 18 Jul 2019 02:37:22 -0700 (PDT) Received: from dawn-kernel.cambridge.arm.com (unknown [10.1.197.116]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 89B973F71A; Thu, 18 Jul 2019 02:37:20 -0700 (PDT) Subject: Re: [PATCHv8 2/5] arm64: dts: qcom: msm8998: Add Coresight support To: saiprakash.ranjan@codeaurora.org, gregkh@linuxfoundation.org, mathieu.poirier@linaro.org, leo.yan@linaro.org, alexander.shishkin@linux.intel.com, mike.leach@linaro.org, robh+dt@kernel.org, bjorn.andersson@linaro.org, devicetree@vger.kernel.org, david.brown@linaro.org, mark.rutland@arm.com Cc: rnayak@codeaurora.org, vivek.gautam@codeaurora.org, sibis@codeaurora.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, marc.w.gonzalez@free.fr References: <3b192063-f31f-b861-d913-61d737cecc57@arm.com> <4854b0f7-6a81-bc87-3e63-d2b7c68a44f6@codeaurora.org> From: Suzuki K Poulose Message-ID: <281e3548-af53-f9a7-b9e4-813b448ab078@arm.com> Date: Thu, 18 Jul 2019 10:37:19 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <4854b0f7-6a81-bc87-3e63-d2b7c68a44f6@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 18/07/2019 10:14, Sai Prakash Ranjan wrote: > Hi Suzuki, > > On 7/18/2019 1:58 PM, Suzuki K Poulose wrote: >> Hi Sai, >> >> >>         etr@6048000 { >>> +            compatible = "arm,coresight-tmc", "arm,primecell"; >>> +            reg = <0x06048000 0x1000>; >>> + >>> +            clocks = <&rpmcc RPM_SMD_QDSS_CLK>, <&rpmcc >>> RPM_SMD_QDSS_A_CLK>; >>> +            clock-names = "apb_pclk", "atclk"; >>> +            arm,scatter-gather; >> >> Please could you confirm that you have tested the scatter-gather mode >> with ETR ? Either via perf/sysfs. Please could you share your results ? >> Unless verified >> this is going to be fatal for the system. >> >> Similarly for other platforms. >> > > Yes I have tested with scatter-gather mode with ETR on all platforms > which I have posted via sysfs(not perf) before on previous versions of > this patch series and no issues were found. And I suppose this was > discussed in v2 of this patch series [1]. Using the sysfs doesn't guarantee that the ETR actually uses SG mode, unless the buffer size selected is > 1M, which is why I am more interested in the perf usage. Alternatively you may configure a larger buffer size (say, 8MB) via: echo 0x800000 > /sys/bus/coresight/.../tmc_etr0/buffer_size > > As said in one of the series initially [1], QCOM msm downstream kernels > have been using scatter gather mode and we haven't seen any fatal issues. > > [1] https://patchwork.kernel.org/patch/10769535/ I haven't seen any test results there either. Cheers Suzuki