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=-4.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 B9222C433E6 for ; Wed, 10 Feb 2021 11:24:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81C0964E3B for ; Wed, 10 Feb 2021 11:24:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229977AbhBJLYN (ORCPT ); Wed, 10 Feb 2021 06:24:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230450AbhBJLVv (ORCPT ); Wed, 10 Feb 2021 06:21:51 -0500 Received: from mail-wm1-x32c.google.com (mail-wm1-x32c.google.com [IPv6:2a00:1450:4864:20::32c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ECBCC0613D6 for ; Wed, 10 Feb 2021 03:21:11 -0800 (PST) Received: by mail-wm1-x32c.google.com with SMTP id i9so1516829wmq.1 for ; Wed, 10 Feb 2021 03:21:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=pZ2lOhhp7f49tVbAR+Dtsh5OoXbTNMSyeigjok338EE=; b=MfzakXwxt4AJwUDYIVb3ykWWpSDBD/cMkBlJLEaBTBjdOowcoRv30y0TL9eTVRKgWC vec8Cp8U/aQslzc6V9f4t9E1DjdkqcJTp77w0vB9MwanIe2ks8BOx0QE4oVxQkxwY9E1 III3UZWf6LrgZILb+nPattMu2tRRxXMyDWayOjHV6qD1ARWyG5tDW01epRbH5mHOTM/k 3YDQaIE3TupLll4+t3QNwYNcR0qlIaGteLXcWfFvHJZlkaOVvQxeiy54qKWMWinxCpke J7EWmItlqbrBaZKtiKQLI6skD4H9jlpeq3V/T72YuvtkNq7jlV9kK9V+e11f7zgx963P 7XQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=pZ2lOhhp7f49tVbAR+Dtsh5OoXbTNMSyeigjok338EE=; b=M+TeARdArR5Re+9uz5tuZqTrlBjJvHonMXwh9Ac5/hVIlac5qzrxWSiima3DrfdDQ5 B9ryzSJwaD2aPNI2zrOpq1sKKW9MCIGUJzfOj6UL40FrFLBIp3sbeLkHa1oFDChomRqb r530ke/r2baYDhvcLbpaVGbOXbVxOWFTFxOUcQa/1hAkCE9RiLM2W9k87w4av92TLeqd d8zBRkWVtcAXEwumjB/F2fxiS1QbL5IDE526zCxXHWscBtuBSpEKVdI/bR1S6HPR+pkT pTy7T3zSv9wG1oZ0N4lY1voMdO/FUYxWM0x5Qb4Y2GEMGzO36lFh1KtVRC9tmnqFwBmF BqEw== X-Gm-Message-State: AOAM530hjGZiTJOS1d+OH6tclp/gQ428y3ameEYlU17wlVuhy8UlSr0G i8kJxxldiIPbW5JAQX73ui9MOXcw2n4= X-Google-Smtp-Source: ABdhPJzUI4XIRYTh4EWkV1K5fsSqIEhbUDutJY3UMEWLBohI8WSU9VZPHm+o+n+KlO+NunY47ZZIkg== X-Received: by 2002:a1c:1f4d:: with SMTP id f74mr2514718wmf.133.1612956069949; Wed, 10 Feb 2021 03:21:09 -0800 (PST) Received: from [192.168.0.108] ([95.87.199.218]) by smtp.gmail.com with ESMTPSA id g62sm2014483wmf.46.2021.02.10.03.21.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Feb 2021 03:21:09 -0800 (PST) Subject: Re: Kernelshark v2 all-black plots area To: Dario Faggioli , Linux Trace Devel References: <89dbef38a1050c31390ce263d51fff1f72a42164.camel@suse.com> From: "Yordan Karadzhov (VMware)" Message-ID: <38b5ea14-cea2-1268-13ef-539fe421e442@gmail.com> Date: Wed, 10 Feb 2021 13:21:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org Hi Dario, On 9.02.21 г. 18:13 ч., Dario Faggioli wrote: > Indeed it does, thanks a lot again. > > Now, if I try "KVM Combo Plot": > - I still see super weird results if I use the KVM clock from last > patch in Tzvetomir series (but I guess I'll report it there). Can you share a screenshot of the one that looks weird. And please do some deeper zooming because it is very hard to judge about the quality of the sync from such a broad time window. > - If I use PTP, that kind of works. > > If I trace a `sleep 1` on the host, the result is like this: > > http://xenbits.xen.org/people/dariof/kernelshark-v2-ptp.png Is this a PTP synchronization? > > So, there is ~ 1 sec of data from the guest, coming from trace-cmd > agent. The host, however, went on and traced a little bit longer, even > after closing the connection. It's not too terrible, I'm just curious > whether this is known or it's something weird and it's only me seeing > it. I think this is normal. But anyway Ceco (Tzvetomir) is the right person to answer questions about the timestamp synchronization. Unfortunately he is on vacation till the end of the week. Thanks a lot! Yordan > > Evaluating the correctness and the accuracy of the synchronization is a > little bit of a challenge, especially for me that I'm not used to it. > And, at least in part, because I still don't have this change in the > kernel I'm using right now, so some kvm_entry trace points are not > recorded, which means it's tricky pairing VMEntries and VMExits: > > https://lore.kernel.org/lkml/160873470698.11652.13483635328769030605.stgit@Wayrath/ > > It should come with 5.11, but I think I'll quickly apply it to the 5.10 > that I'm running, to try to understand better hat's going on.