From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: Too much VCPUS makes domU high CPU utiliazation Date: Wed, 18 May 2011 12:39:50 -0400 Message-ID: <20110518163950.GA20543@dumpdata.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: MaoXiaoyun Cc: george.dunlap@eu.citrix.com, xen devel List-Id: xen-devel@lists.xenproject.org On Thu, May 19, 2011 at 12:19:11AM +0800, MaoXiaoyun wrote: > > HI: > > I have a host with 16 physical CPUS. Dom0 has 4 VCPUS. > > When only start a domU-A(windows 2003 x86 64rc 2) with 16 VCPUS, it starts quickly and eveything is fine. > > But if I first start domU-B, which has 2VCPUS, domU-C 4VCPUS, and domU-D 8 VCPUS, later I start DomUA again, > (so we have total 34 VCPUS, plus dom0), it will takes very long time for domU-A to start ,and during the start, its CPU > utilizaiton is around 800% from xm top, after its start, it response very slow in VNC, ans CPU utiliazation keeps high. > And right after I destoy other 3 domUs, domUA CPU drops to normal. You might be missing some patches for the Dom0 irq round-robin code. Is your Dom0 2.6.32 pvops? Look for these patches in your git log: xen: events: Remove redundant clear of l2i at end of round-robin loop xen: events: Make round-robin scan fairer by snapshotting each l2 word once only xen: events: Clean up round-robin evtchn scan. xen: events: Make last processed event channel a per-cpu variable. xen: events: Process event channels notifications in round-robin order. > > It might relate to CPU schedule, btw, my xen is 4.0.1. > > Any comments? > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel