From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: linux-aio usable? Date: Mon, 08 Mar 2010 11:10:29 +0200 Message-ID: <4B94BF05.20609@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Bernhard Schmidt Return-path: Received: from mx1.redhat.com ([209.132.183.28]:8491 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752676Ab0CHJKq (ORCPT ); Mon, 8 Mar 2010 04:10:46 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 03/08/2010 03:46 AM, Bernhard Schmidt wrote: > Hi, > > sorry for this pretty generic question, I did not find any real pros and > cons on the net anywhere, but I might just have missed them. > > In a pure x86_64 environment (~2.6.32 vanilla kernel, 0.12.3 qemu-kvm), > is enabling linux-aio in KVM a good idea? Yes. > What are the > advantages/disadvantages? It's faster. > Are there any potential pitfalls? > It won't work well unless running on a block device (partition or LVM). > The reason I'm asking is that there has been some traffic on the list > about it, so it seems to be something people want to get working. > qemu-kvm in Ubuntu Lucid is currently not compiled with that option. > I've made a local version with aio and it seems to work fine (and > performs a bit better at first glance). > > Is there any reason one should not compile that feature by default? > Not to my knowledge. > Does it do anything if not explicitly run with aio=native? > IIUC, no. -- error compiling committee.c: too many arguments to function