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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 B5A95C56202 for ; Fri, 20 Nov 2020 13:43:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5962C2236F for ; Fri, 20 Nov 2020 13:43:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="mDMjpFtO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728143AbgKTNnY (ORCPT ); Fri, 20 Nov 2020 08:43:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:49290 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727379AbgKTNnY (ORCPT ); Fri, 20 Nov 2020 08:43:24 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1605879802; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=tCDsQj6tpdtm2iyRBssF1fODDeRllwGPFgtsMTC3qxQ=; b=mDMjpFtOk8KMiXMpTevE0GIGE3h5IFRVt+lg+br97GPuGcyn0rxg+KaT1pG+Rz6Ym5+p5s xAZGW8fzG0syx3uoIZHkCd5780KLArCJX2II3wsCq3EdrD/HbJdSAGgkBEim4v+ZfCDWQi 7d6RD8Tfb1Zr1Jdx9NTV/1hf/LDXMew= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 4F5B3ABD6; Fri, 20 Nov 2020 13:43:22 +0000 (UTC) Message-ID: <849f846631f3014c3eff7f37a7d61493e2af66a9.camel@suse.com> Subject: Accuracy of traces sync [Was: Re: [PATCH] Fix `make -jN trace-cmd gui`] From: Dario Faggioli To: "Yordan Karadzhov (VMware)" , Steven Rostedt Cc: linux-trace-devel@vger.kernel.org Date: Fri, 20 Nov 2020 14:43:21 +0100 In-Reply-To: <02672da2-8b62-a573-786d-1cb8f5970e85@gmail.com> References: <160564780533.18208.2518938894299815863.stgit@toolbox-dario-user-work> <20201119220910.1a8ec625@oasis.local.home> <64d58c3297d6915362678c5799bd3d363489bda3.camel@suse.com> <02672da2-8b62-a573-786d-1cb8f5970e85@gmail.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-h8Y6z9ysSZ7DVD1MKL11" User-Agent: Evolution 3.38.1 (by Flathub.org) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org --=-h8Y6z9ysSZ7DVD1MKL11 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2020-11-20 at 14:32 +0200, Yordan Karadzhov (VMware) wrote: > On 20.11.20 =D0=B3. 14:06 =D1=87., Dario Faggioli wrote: > > >=20 > > Yep, sure! I followed the talks you've been giving about it at > > events, and I even played a little with what you have here: > >=20 > > https://github.com/yordan-karadzhov/kernel-shark-2.alpha > >=20 > > The host-guest tracing part, as I think you can guess. >=20 > Ciao Dario, > Hey! > I am very happy to hear that. The timestamp synchronization patches > for=20 > trace-cmd are almost ready to go upstream. >=20 Yes, I tried those patches! In fact, now that I have you here, do you mind if I change the subject and ask a quick question about them? So, you often say that "the accuracy of the synchronization protocol is XX ms". Now, I guess that means that an event in the guest and the corresponding event in the host (or vice versa) are XX ms apart. And that's even after the synchronization of the two traces, is that right? Question is, how do you measure that? Sure, I can look manually for an occurrence of the pattern that I described above: i.e., an event in the guest, then the corresponding one in the host and compute the difference between the timestamps. But do you have a way to do so automatically, or with a script/program, etc? I saw that the series included a patch which was meant at debugging and profiling PTP, but even with that one applied and having it generate the graphs, I have not been able to get that info without manual inspection. > And we are currently reviewing a beta version of KernelShark_2 that > will=20 > include the guest/host visualization. > As Steven said: stay tuned! >=20 You bet I will. :-P Thanks and Regards --=20 Dario Faggioli, Ph.D http://about.me/dario.faggioli Virtualization Software Engineer SUSE Labs, SUSE https://www.suse.com/ ------------------------------------------------------------------- <> (Raistlin Majere) --=-h8Y6z9ysSZ7DVD1MKL11 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEES5ssOj3Vhr0WPnOLFkJ4iaW4c+4FAl+3x/kACgkQFkJ4iaW4 c+59yw//QIdq3fb1fciqQulR6pcZnaV5B9aTsbiD7wTG64vUf6GAmsjrnYy6ckpU 6a4ExQFNiRbXpoZltvhi2PyiK/aMIF2/dyhNwlZNixWccH3u/bF0kKY92nWX7jHr OdopbZMr7StxnRdigchkJfzbl5H/qw4Fv1+TV7EJaP8HU5i5W1xSdkc7jBBazDen oWaj/0oLoUO2ONC4A5pjDeDI4OhaH9CtiRhnAMeSD03x9xoCXMgbr8MnUgsjFJnT PBewRCJEVawAkO669hcKgVP4fnHmhji9/N0K7MmI9egij54ciZBYjMelQ9ChOwVp nv4wYgTZkv9hsJ6AIgzQ7dywoJrFaew76kIqBtJtbZYuMb8mtTgEE3cdbJgOaQpO uLh7WZji6Buo06itGjRhTZG7TsJTPL/g6kd1qUw79eRXQXS7riDt2NFXV641ORA8 +2FDwm+j26kOoaXMOngkJjIZqchmXW63kr/9e4FyDaOx481vnzVctLs0z/gFiqOq JTmcHjg9Dn6OqRn2zqdAzuex9bzqXVFoqMjVWxl5xUKrdvqP9K/aFwmRJsH3i2AU 5oTYnie/E3GhP08MKOoFPA/rm4fKLznRKuIxaWm2SNOJDZMqen28Rh56hBg7igZe CCMBr9Ad32pp63jR9x7j/+gNG2sD619OiQQty2ibSc3aL5Iyv7Y= =p37O -----END PGP SIGNATURE----- --=-h8Y6z9ysSZ7DVD1MKL11--