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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 C568DC74A4B for ; Thu, 11 Jul 2019 10:24:50 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9BB2E20872 for ; Thu, 11 Jul 2019 10:24:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9BB2E20872 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40194 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hlWFt-0004w2-Na for qemu-devel@archiver.kernel.org; Thu, 11 Jul 2019 06:24:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33469) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hlWFM-0004NS-Fc for qemu-devel@nongnu.org; Thu, 11 Jul 2019 06:24:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hlWFL-0001D5-AD for qemu-devel@nongnu.org; Thu, 11 Jul 2019 06:24:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:25470) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hlWFL-0001Cr-4c for qemu-devel@nongnu.org; Thu, 11 Jul 2019 06:24:15 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2C5F63082145; Thu, 11 Jul 2019 10:24:14 +0000 (UTC) Received: from work-vm (unknown [10.36.118.40]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6141D194B5; Thu, 11 Jul 2019 10:24:13 +0000 (UTC) Date: Thu, 11 Jul 2019 11:24:10 +0100 From: "Dr. David Alan Gilbert" To: Lin Ma Message-ID: <20190711102410.GH3971@work-vm> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Thu, 11 Jul 2019 10:24:14 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] migrate_set_speed has no effect if the guest is using hugepages. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "qemu-devel@nongnu.org" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Lin Ma (LMa@suse.com) wrote: > Hi all, Hi Lin, > When I live migrate a qemu/kvm guest, If the guest is using huge pages, I found that > the migrate_set_speed command had no effect during stage 2. Can you explain what you mean by 'stage 2'? > It was caused by commit 4c011c3 postcopy: Send whole huge pages > > I'm wondering that is it by design or is it a bug waiting for fix? This is the first report I've seen for it. How did you conclude that 4c011c3 caused it? While I can see it might have some effect on the bandwidth management, I'm surprised it has this much effect. What size huge pages are you using - 2MB or 1GB? I can imagine we might have a problem that since we only do the sleep between the hugepages, if we were using 1GB hugepages then we'd see [sleep][sleep] which isn't as smooth as it used to be. Can you give me some more details of your test? Dave > > Thanks, > Lin -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK