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RE: [Xen-devel] [Patch] Buffer disk I/O requests

To: "Han, Weidong" <weidong.han@xxxxxxxxx>, "Keir Fraser" <keir@xxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [Patch] Buffer disk I/O requests
From: "Ian Pratt" <Ian.Pratt@xxxxxxxxxxxx>
Date: Mon, 14 May 2007 14:02:07 +0100
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Thread-topic: [Xen-devel] [Patch] Buffer disk I/O requests
> Buffered disk I/O improves disk I/O port access performance. It's
> similar to buffered vga which is mmio. We ran SysBench random file I/O
> test and found it reached about 10% improvement.

How does it compare to just using the SCSI HBA support that got checked
in a few days ago (in the qemu-dm 0.9.0 upgrade)?

If we're going to add support for enabling buffering of ioport accesses
beyond what we currently special case for the VGA it should be via a
generic interface used by qemu to register sets of ports with xen and
configure how they will be handled. 


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