From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 09/10] Exit loop if we have been there too long Date: Wed, 01 Dec 2010 14:35:57 +0200 Message-ID: <4CF6412D.5030601@redhat.com> References: <9b23b9b4cee242591bdb356c838a9cfb9af033c1.1290552026.git.quintela@redhat.com> <4CF45D67.5010906@codemonkey.ws> <4CF4A478.8080209@redhat.com> <4CF5008F.2090306@codemonkey.ws> <4CF5030B.40703@redhat.com> <4CF50783.90402@codemonkey.ws> <4CF509C1.9@redhat.com> <20101201102034.07eff649.yoshikawa.takuya@oss.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Takuya Yoshikawa , Anthony Liguori , Paolo Bonzini , qemu-devel@nongnu.org, kvm-devel To: Juan Quintela Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43397 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751461Ab0LAMgF (ORCPT ); Wed, 1 Dec 2010 07:36:05 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 12/01/2010 03:52 AM, Juan Quintela wrote: > > - 512GB guest is really the target? > > no, problems exist with smaller amounts of RAM. with 16GB guest it is > trivial to get 1s stalls, 64GB guest, 3-4s, with more memory, migration > is flaky to say the less. > > > - how much cpu time can we use for these things? > > the problem here is that we are forced to walk the bitmap too many > times, we want to do it less times. How much time is spent walking bitmaps? Are you sure this is the problem? > > - how many dirty pages do we have to care? > > default values and assuming 1Gigabit ethernet for ourselves ~9.5MB of > dirty pages to have only 30ms of downtime. 1Gb/s * 30ms = 100 MB/s * 30 ms = 3 MB. -- error compiling committee.c: too many arguments to function