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From: Jeff Dike <jdike@addtoit.com>
To: Chris Lightfoot <chris@ex-parrot.com>
Cc: user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [uml-devel] UBD performance
Date: Sun, 9 Oct 2005 14:45:42 -0400	[thread overview]
Message-ID: <20051009184542.GC4901@ccure.user-mode-linux.org> (raw)
In-Reply-To: <z/jPSbKkgHHL.jbObjJNOGZsiVW/jm0lNOg@sphinx.mythic-beasts.com>

On Sat, Oct 08, 2005 at 05:32:10PM +0100, Chris Lightfoot wrote:
> Jeff Dike also has an AIO reimplementation of UBD in the
> works, but I haven't had a chance to look at it yet.

Why don't you look at UML with the AIO stuff applied?  It's pretty certain 
that the one-at-a-time pseudo-AIO gives you close to synchronous
performance when you have a lot of IO.  The AIO work is intended to
fix that, and if it doesn't, I like to know why.

If you do want to play with the current stuff, I think you can wash
out the effects of the pseudo-AIO stuff by slowing down the host and
having it do symchronous I/O.  If there is still a major difference
between UML and the host, it would be interesting to know why.

				Jeff


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  parent reply	other threads:[~2005-10-09 18:52 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-08 16:32 [uml-devel] UBD performance Chris Lightfoot
2005-10-09  8:49 ` [uml-devel] " Chris Lightfoot
2005-10-09 18:45 ` Jeff Dike [this message]
2005-10-09 22:51   ` [uml-devel] " Chris Lightfoot
2005-10-10  1:35     ` Jeff Dike
2005-10-10  9:10       ` Chris Lightfoot
2005-10-10 14:38         ` Jeff Dike
2005-10-10 15:44           ` Chris Lightfoot

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