From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Question on skip_emulated_instructions() Date: Thu, 08 Apr 2010 10:37:06 +0300 Message-ID: <4BBD87A2.5000909@redhat.com> References: <4BBAB46B.9010405@lab.ntt.co.jp> <20100406100522.GW5235@redhat.com> <20100407154324.GF303@redhat.com> <4BBCC2C9.1040301@redhat.com> <4BBD6959.6080003@lab.ntt.co.jp> <20100408065620.GH303@redhat.com> <4BBD8628.3060904@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , kvm@vger.kernel.org, Marcelo Tosatti To: Yoshiaki Tamura Return-path: Received: from mx1.redhat.com ([209.132.183.28]:29842 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751969Ab0DHHhK (ORCPT ); Thu, 8 Apr 2010 03:37:10 -0400 In-Reply-To: <4BBD8628.3060904@lab.ntt.co.jp> Sender: kvm-owner@vger.kernel.org List-ID: On 04/08/2010 10:30 AM, Yoshiaki Tamura wrote: > > To answer your question, it should be possible to implement. > The down side is that after going into KVM to make the guest state to > consistent, we need to go back to qemu to actually transfer the guest, > and this bounce would introduce another overhead if I'm understanding > correctly. Yes. It should be around a microsecond or so, given you will issue I/O after this I don't think this will affect performance. > And yes, all I need is some consistent state to resume VM from, which > must be able to continue I/O operations, like writing to disks and > sending ack over the network. If I can guarantee this, sending the VM > state after completing output is acceptable. > I suggest you start with this. If it turns out performance is severely impacted, we can revisit instruction completion. If performance is satisfactory, then we'll be able to run Kemari with older kernels. -- error compiling committee.c: too many arguments to function