From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM call agenda for Feb 9 Date: Tue, 09 Feb 2010 16:18:33 +0200 Message-ID: <4B716EB9.2060006@redhat.com> References: <20100209012851.GJ25751@x200.localdomain> <4B710714.1020109@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org To: Chris Wright Return-path: Received: from mx1.redhat.com ([209.132.183.28]:64586 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754508Ab0BIOSl (ORCPT ); Tue, 9 Feb 2010 09:18:41 -0500 In-Reply-To: <4B710714.1020109@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 02/09/2010 08:56 AM, Avi Kivity wrote: > On 02/09/2010 03:28 AM, Chris Wright wrote: >> Please send in any agenda items you are interested in covering. > > hpet overhead on large smp guests > > I measured hpet consuming about a half a core's worth of cpu on an > idle Windows 2008 R2 64-way guest. This is mostly due to futex > contention, likely from the qemu mutex. > > Options: > - ignore, this is about 1% of the entire system (but overhead might > increase greatly if a workload triggers more hpet accesses) > - push hpet into kernel, with virtio-net, virtio-blk, and kernel-hpet, > there's little reason to exit into qemu > - rcuify/fine-grain qemu locks > - implement hyper-v timers -- error compiling committee.c: too many arguments to function