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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6201AC61DA4 for ; Thu, 9 Mar 2023 11:39:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231560AbjCILjC (ORCPT ); Thu, 9 Mar 2023 06:39:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231452AbjCILjB (ORCPT ); Thu, 9 Mar 2023 06:39:01 -0500 Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 877906A9F1 for ; Thu, 9 Mar 2023 03:39:00 -0800 (PST) Received: by mail-pl1-x62b.google.com with SMTP id n6so1649245plf.5 for ; Thu, 09 Mar 2023 03:39:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1678361940; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=kYsJiKyy+lTF4z1H2mSxKLr6ADWPzBDDBXemJTJ36Ks=; b=qrYsSdWwsRhgnb8uDOtCBtoRToUCHBFxclejPIK5uKZNh5GhkUHLsx+shQWLFKnQRb lxqZQ7iqj1Rp1ij8OB5I0DCtrrEKznEBMWwEe6u77MBH82sEen6sPY+AK54YhhVv6Zov vVErC58toiN46BPkGNds4B1oKmfDQo1P/GuPXKmcewJs6zIMxMm2vzB9g83cmrN9i5As 3jOPPHhtpAPnN92dBR7TQxAt+FDacKrAzodTNH8J3HQmZbftdnunON5V2OXxGUfugwm2 fiLZlmKMfYQPp/+CjWQfWUNFi6694qDSqu+QN+UfHSYk0Ofg9B5XTmduB99kk4/x/5ov zsgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678361940; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=kYsJiKyy+lTF4z1H2mSxKLr6ADWPzBDDBXemJTJ36Ks=; b=Q8CZUqVo8FcvmlldsJy/ksh10ncitKut7awuNZlqPxhg9tmwwbnPu7lfa+hAPZrmW4 S2sjbe1Ng6+tnio/z3TlBwjXptxtK8cJp9dRVRbYzyEez3ptfndtLU+Xm+ItCY8lrr4M xR1RuLyuNexAvPINp+DNoz9QlZsahTpbmwYMDywFLVW02J16bRsYvGh56VMoCbVbqCQN +tRX1sgT/0MDgcKRSh9XrEWSZZkLo0/TqxNR6lyzXpk0vGGZh3cGYmS4AKY3d9H/AbJQ I5h34uUcKa75H345+j/LwZBzY7QcT814cbqZTG5wKuJeDaYFYOHTJPW8GxWxLJ86hBuq akVw== X-Gm-Message-State: AO0yUKU/Zmz/TPdYS/GtMHYEi0f4UAGn4ghYhzaNikBzzyK/JSfn1K9S WX6nCWjTC43zYxNgDK4MONwyNw== X-Google-Smtp-Source: AK7set9BcKzdqEvVwBm1rR1GGtYhrdXP+ByCdfjj8e7gOOwRGmWRyMbWRum5esDB5AWQTC0hTpRL3g== X-Received: by 2002:a17:90b:4a4c:b0:237:9cc7:28a4 with SMTP id lb12-20020a17090b4a4c00b002379cc728a4mr22842172pjb.14.1678361939798; Thu, 09 Mar 2023 03:38:59 -0800 (PST) Received: from leoy-yangtze.lan ([107.151.177.133]) by smtp.gmail.com with ESMTPSA id mm14-20020a17090b358e00b0023493354f37sm1427084pjb.26.2023.03.09.03.38.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Mar 2023 03:38:59 -0800 (PST) Date: Thu, 9 Mar 2023 19:38:51 +0800 From: Leo Yan To: Yang Shi Cc: James Clark , linux-perf-users@vger.kernel.org, LAK , coresight@lists.linaro.org, Linux Kernel Mailing List , mathieu.poirier@linaro.org, adrian.hunter@intel.com, Jiri Olsa , acme@redhat.com, mike.leach@linaro.org, Will Deacon , suzuki.poulose@arm.com Subject: Re: [BUG] perf: No samples found when using kcore + coresight Message-ID: <20230309113851.GF19253@leoy-yangtze.lan> References: <8ca2b07e-674e-afb6-ff12-87504f51f252@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org Hi Yang, On Wed, Mar 08, 2023 at 11:56:38AM -0800, Yang Shi wrote: [...] > > Dumping raw events could show the events from the bad data file. But > > it has zero samples after event collapse. > > > > The only difference is --kcore inserted a new text_poke dummy event. > > It seems coresight also inserted a dummy event with my command but > > your command didn't. So it seems like the two dummy events confused > > event collapse. > > > > The text_poke dummy event is added by commit > > f42c0ce573df79d1b8bd169008c994dcdd43585a ("perf record: Always get > > text_poke events with --kcore option"). If I reverted this commit, > > then it works. But I'm not sure whether this is the right fix or real > > root cause or not. Or coresight shouldn't insert its own dummy event? > > It seems like coresight needs to insert the dummy event if > full_auxtrace is on IIUC. So it sounds like event collapse can't > handle such a case? I am struggling to understand the meaning "event collapse" :) I reviewed your shared dump, the bad and good perf data both contain the dummy event with 'text_poke = 1'. Could you confirm the shared dump in your previous email is correct or not? > I also tried v5.19 (before "perf record: Always > get text_poke events with --kcore option", which was merged in v6.0), > it works. So it seems like a regression. Yeah, we need to fix it. I am not sure the Linux kernel for Arm64 supports text poke or not (kernel needs some specific handling when alter instructions), the kernel change is the prerequisites. On the other hand, in the current code cs-etm misses to handle the event PERF_RECORD_TEXT_POKE in the function cs_etm__process_event(). This might be the cause for the failure. Do you mind to share the bad perf.data file with James and me? Thanks, Leo