Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17C60C6FD1E for ; Tue, 7 Mar 2023 10:33:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230300AbjCGKdj (ORCPT ); Tue, 7 Mar 2023 05:33:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230129AbjCGKdD (ORCPT ); Tue, 7 Mar 2023 05:33:03 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 13F0D26A3; Tue, 7 Mar 2023 02:32:47 -0800 (PST) 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 0956B113E; Tue, 7 Mar 2023 02:33:30 -0800 (PST) Received: from [192.168.1.3] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 090593F71A; Tue, 7 Mar 2023 02:32:44 -0800 (PST) Message-ID: <8ca2b07e-674e-afb6-ff12-87504f51f252@arm.com> Date: Tue, 7 Mar 2023 10:32:33 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [BUG] perf: No samples found when using kcore + coresight To: Yang Shi Cc: linux-perf-users@vger.kernel.org, LAK , coresight@lists.linaro.org, Linux Kernel Mailing List , leo.yan@linaro.org, mathieu.poirier@linaro.org, adrian.hunter@intel.com, Jiri Olsa , acme@redhat.com, mike.leach@linaro.org, Will Deacon , suzuki.poulose@arm.com References: Content-Language: en-US From: James Clark In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/03/2023 21:13, Yang Shi wrote: > Hi, > > I'm seeking some help regarding perf record --kcore + coresight. When > I tracing with perf record --kcore -e cs_etm ... , perf report shows > "The perf.data/data data has no samples!". > > I tried other combinations: > 1. perf record --kcore (w/o using coresight): works > 2. perf record -e cs_etm ... : works > 3. Manually copy kcore with perf buildid-cache, then run perf record > -e cs_etm... : works > > So just "perf record --kcore -e cs_etm ..." doesn't work. > > I'm using v6.2 kernel and the perf is built from the same kernel > source with OpenCSD 1.4. Also attached the sample file generated by > perf. > > Any suggestion is appreciated. > > Thanks, > Yang Hi Yang, I don't see any issue with this command and I still get samples: perf record -e cs_etm// --kcore -- true You might want to try running both record and report in verbose and stdio mode (-vvv --stdio) to see if you see any warnings. I can't think of any way --kcore would cause an issue because all it does is save kcore into the .debug cache rather than affecting the actual perf.data file. Are you running perf report in the same place the recording was made? Or on another system? James