From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Windows slow boot: contractor wanted Date: Tue, 21 Aug 2012 12:00:03 +0300 Message-ID: <50334E13.8020100@redhat.com> References: <20120816104727.GA17166@alpha.arachsys.com> <502CDC0D.9080004@redhat.com> <20120817123642.GA16736@alpha.arachsys.com> <5030F273.5080706@redhat.com> <20120820135656.GA16676@alpha.arachsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Rik van Riel To: Richard Davies Return-path: Received: from mx1.redhat.com ([209.132.183.28]:7028 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752597Ab2HUJAU (ORCPT ); Tue, 21 Aug 2012 05:00:20 -0400 In-Reply-To: <20120820135656.GA16676@alpha.arachsys.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/20/2012 04:56 PM, Richard Davies wrote: > We're running host kernel 3.5.1 and qemu-kvm 1.1.1. > > I hadn't though about it, but I agree this is related to cpu overcommit. The > slow boots are intermittent (and infrequent) with cpu overcommit whereas I > don't think it occurs without cpu overcommit. > > In addition, if there is a slow boot ongoing, and you kill some other VMs to > reduce cpu overcommit then this will sometimes speed it up. > > I guess the question is why even with overcommit most boots are fine, but > some small fraction then go slow? Could be a bug. The scheduler and the spin-loop handling code fight each other instead of working well. Please provide snapshots of 'perf top' while a slow boot is in progress. -- error compiling committee.c: too many arguments to function