From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Jan_Kundr=E1t?= Subject: Re: poor I/O performance on domU Date: Thu, 13 Jan 2005 18:08:18 +0100 Message-ID: <41E6AB02.6020801@fzu.cz> References: <41E69C98.7090804@fzu.cz> <1105635651.25281.2.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1105635651.25281.2.camel@localhost> Sender: xen-devel-admin@lists.sourceforge.net Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Anthony Liguori Cc: xen-devel List-Id: xen-devel@lists.xenproject.org Anthony Liguori wrote: > I think that's a reasonable answer. It should be easy to test though. > Try your same test on dom0 and use /dev/loopN where N is the loopback > device that has your rootfs on it. > Only rootfs is exported from loopback device and I'm benchmarking access to dom0's /dev/hda exported to domU as read-only. As the rootfs image is quite small (16MB), I can't easily test access speeds because it will fit into cache. > The difference between testing /dev/loopN access on dom0 and the virtual > block device on domU should tell you the Xen-imposed performance > penalty. > > I did a quick test on my system and there was a 50% slowdown using the > loopback device doing your test so I imagine it's that. Accessing exported loopback or some other device? -jkt -- cd /local/pub && more beer > /dev/mouth ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt