From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: sync guest calls made async on host - SQLite performance Date: Wed, 14 Oct 2009 17:54:23 -0500 Message-ID: <4AD6569F.80803@codemonkey.ws> References: <4ACE0196.9010904@gmail.com> <4ACF89CB.5020406@gmail.com> <4AD1A27A.4060307@redhat.com> <20091013223714.GB16152@lst.de> <4AD5B00D.102@redhat.com> <20091014134122.GA14235@lst.de> <4AD602C8.4090603@redhat.com> <20091014170215.GA22621@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Matthew Tippett , Dustin Kirkland , RW , kvm@vger.kernel.org To: Christoph Hellwig Return-path: Received: from mail-yw0-f176.google.com ([209.85.211.176]:54513 "EHLO mail-yw0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758760AbZJNXAz (ORCPT ); Wed, 14 Oct 2009 19:00:55 -0400 Received: by ywh6 with SMTP id 6so288862ywh.4 for ; Wed, 14 Oct 2009 16:00:19 -0700 (PDT) In-Reply-To: <20091014170215.GA22621@lst.de> Sender: kvm-owner@vger.kernel.org List-ID: Christoph Hellwig wrote: > On Thu, Oct 15, 2009 at 01:56:40AM +0900, Avi Kivity wrote: > >> Does virtio say it has a write cache or not (and how does one say it?)? >> > > Historically it didn't and the only safe way to use virtio was in > cache=writethrough mode. Which should be the default on Ubuntu's kvm that this report is concerned with so I'm a bit confused. Avi's patch is a performance optimization, not a correctness issue? Regards, Anthony Liguori