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=-13.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 7B001C433ED for ; Fri, 23 Apr 2021 15:49:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 321CE613E1 for ; Fri, 23 Apr 2021 15:49:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231445AbhDWPua (ORCPT ); Fri, 23 Apr 2021 11:50:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230294AbhDWPua (ORCPT ); Fri, 23 Apr 2021 11:50:30 -0400 Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com [IPv6:2607:f8b0:4864:20::834]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7CFBC061574 for ; Fri, 23 Apr 2021 08:49:53 -0700 (PDT) Received: by mail-qt1-x834.google.com with SMTP id u8so36632739qtq.12 for ; Fri, 23 Apr 2021 08:49:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=eeu8xMGkdnS5HMwLj7trKy/RiVMahP7x1qhJLmXfrkE=; b=gGnivacxU9bYFNLSoVNiwDhslkTDUXNGWaZmgrJYicbXsmgycvMU7jUu3ZrjwVPsct pHuy2oeJSA6Fnj9ZQVeyAk4vdHx/bMpE4kPl4R//UF2nScaZ6DYYKMCzE+HkmbABSALX D+eRImw0TAZgaGtJ/DwOZoygCtEqSnIAJBUIcsxzK1vTPix+GWmAqEHfr4qqO8vNwSlZ KS+SyQhAZkojh7CpRCixujHRvPX24Stba4H77HuiN1XIhQX5VSjUQfrLB5Xz9wD4OdAU SIiJWpvowz6V2FCiuAE3xVeCk7oHkIdV+5m5BapAY6L6sASfuPypZKtuT8maNdaa2jdY zNaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=eeu8xMGkdnS5HMwLj7trKy/RiVMahP7x1qhJLmXfrkE=; b=LbWis7mB2QpWscoaDnVEleza6tqBH6Iw0AYWDzstiodxnGhkQwASuvh9aV24VfVw3M JUCVe6gQ3TPGhp+NpcrixB/cgNxiMatvyPBgLOs8tdDQffvedpahKgUdvJ4R3qkczPiw kLNoGjjQ/LiEbBiesM8c7LyJlTRYR/4p+vPPhFOUe6MJHpPHth/2TE/tIflkxIKJFAOt mpBrhhVEY0cax77OY/v/7OH8Bg0T4SpqWVh6o35zr8uKXuRm20DD73GUtTNsuZTRkWh1 N57/Xa2zgyVCLtIE1KpWm2weTqTiWyAGRd0QDRGvMIph7E5eLZY3j9UzvoqwE6zZwVtT xxLQ== X-Gm-Message-State: AOAM531X5kRqq/TDi+8kY9PL3QZZChFV+mgIf5dUlgoybxY2B+CSlBQ9 n1qDQtLULA31c4tac1Dza+0ybd0zbO/sSVsY5F4mdg== X-Google-Smtp-Source: ABdhPJzN6diwL1uiaHNXB755M2hR/E8WFK02dS3YR2XPBxByHtOBTMSklV9X0UYXorzf0/hXpTkjdgdFdJ17YUkof2k= X-Received: by 2002:ac8:7766:: with SMTP id h6mr4466057qtu.258.1619192992858; Fri, 23 Apr 2021 08:49:52 -0700 (PDT) MIME-Version: 1.0 References: <20210422153845.3e6e9304@gandalf.local.home> <20210422154830.52f3e4f5@gandalf.local.home> <20210422160313.2eee1f77@gandalf.local.home> <20210423073309.240599e1@gandalf.local.home> In-Reply-To: <20210423073309.240599e1@gandalf.local.home> From: Joel Fernandes Date: Fri, 23 Apr 2021 11:49:41 -0400 Message-ID: Subject: Re: Instructions for clock sync for tracing host/guest To: Steven Rostedt Cc: Tzvetomir Stoyanov , "Yordan Karadzhov (VMware)" , Linux Trace Devel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Fri, Apr 23, 2021 at 7:33 AM Steven Rostedt wrote: > > Hi Joel, > > FYI, VMware gave everyone the day off today, so don't expect any real > responses till next week. Got it. > On Fri, 23 Apr 2021 04:37:40 -0400 > Joel Fernandes wrote: > > > Apologies for the top post as I'm on Gmail mobile and only half awake at > > 4.30am. I should check but can we just scrape the crosvm PIDs from the > > host trace itself ? The vCPU threads are in scheduler events in the host > > trace. Of course that wouldn't work if we don't have events. Let me know if > > that works for you or if I should find another way. > > > > By the way if sync is supposed to fall back to the ptp algo, why did it not > > fallback for me? > > If both guest and host support an algo, it will use the one that has the > best synchronization (like KVM). If the guest says it supports KVM and the > host says it supports KVM, then it will use it. The question now remains, > did one of them lie? ;-) Good question, will try to debug and see what each said. > > Other thoughts: > > - it would be cool if trace cmd agent was run by the host directly on the > > guest. That might eliminate a step. I can try to see if that's possible > > with crosvm but it's not super high priority. > > Not sure what you mean by that. I meant that currently, doing "trace-cmd agent" in the guest is an extra step. I'd rather the "trace-cmd record" on the host spawn the agent within the guest somehow, thus eliminating that extra step. > > Yes thanks for sending me any patches and happy to try. > > Feel free to send us patches too! ;-) Yes, certainly. My first attempt was to see if I could hit the ground running with my VM problems, if trace-cmd was in sufficient shape. Looks like trace-cmd is almost there and happy to help with the best of my ability to write any patches. > Anyway, see you next week. You too, thanks, -Joel > > -- Steve