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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 69367C433FF for ; Tue, 30 Jul 2019 15:56:34 +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 3F2AE2064A for ; Tue, 30 Jul 2019 15:56:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F2AE2064A 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]:34128 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsUUL-0002CO-H4 for qemu-devel@archiver.kernel.org; Tue, 30 Jul 2019 11:56:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48364) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsUTv-0001nj-Lg for qemu-devel@nongnu.org; Tue, 30 Jul 2019 11:56:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hsUTt-00039a-Jw for qemu-devel@nongnu.org; Tue, 30 Jul 2019 11:56:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41637) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hsUTt-00039A-Eu for qemu-devel@nongnu.org; Tue, 30 Jul 2019 11:56:05 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B06B5DF26; Tue, 30 Jul 2019 15:56:04 +0000 (UTC) Received: from redhat.com (ovpn-116-30.ams2.redhat.com [10.36.116.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4B31960BF7; Tue, 30 Jul 2019 15:56:02 +0000 (UTC) From: Juan Quintela To: Ivan Ren In-Reply-To: <1564464992-22305-1-git-send-email-ivanren@tencent.com> (Ivan Ren's message of "Tue, 30 Jul 2019 13:36:32 +0800") References: <1564464992-22305-1-git-send-email-ivanren@tencent.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) Date: Tue, 30 Jul 2019 17:56:00 +0200 Message-ID: <87d0hrjz3j.fsf@trasno.org> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 30 Jul 2019 15:56:04 +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] [PATCH] migration: always initial ram_counters for a new migration 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: , Reply-To: quintela@redhat.com Cc: dgilbert@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Ivan Ren wrote: > From: Ivan Ren > > This patch fix a multifd migration bug in migration speed calculation, this > problem can be reproduced as follows: > 1. start a vm and give a heavy memory write stress to prevent the vm be > successfully migrated to destination > 2. begin a migration with multifd > 3. migrate for a long time [actually, this can be measured by transferred bytes] > 4. migrate cancel > 5. begin a new migration with multifd, the migration will directly run into > migration_completion phase > > Reason as follows: > > Migration update bandwidth and s->threshold_size in function > migration_update_counters after BUFFER_DELAY time: > > current_bytes = migration_total_bytes(s); > transferred = current_bytes - s->iteration_initial_bytes; > time_spent = current_time - s->iteration_start_time; > bandwidth = (double)transferred / time_spent; > s->threshold_size = bandwidth * s->parameters.downtime_limit; > > In multifd migration, migration_total_bytes function return > qemu_ftell(s->to_dst_file) + ram_counters.multifd_bytes. > s->iteration_initial_bytes will be initialized to 0 at every new migration, > but ram_counters is a global variable, and history migration data will be > accumulated. So if the ram_counters.multifd_bytes is big enough, it may lead > pending_size >= s->threshold_size become false in migration_iteration_run > after the first migration_update_counters. > > Signed-off-by: Ivan Ren Reviewed-by: Juan Quintela