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Re: [Xen-devel] poor domU VBD performance.

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] poor domU VBD performance.
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 31 Mar 2005 20:10:58 +0100
Cc: Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>, Xen development list <xen-devel@xxxxxxxxxxxxxxxxxxx>, Kurt Garloff <garloff@xxxxxxx>, Philip R Auld <pauld@xxxxxxxxxxx>, Vincent Hanquez <tab@xxxxxxxxx>, Jens Axboe <axboe@xxxxxxx>, Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
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On 31 Mar 2005, at 20:07, Keir Fraser wrote:

Since all the bio's that I queue up in a single invocation of dispatch_rw_block_io() will actually be adjacent to each other (because they're all from the same scatter-gather list)

I should add: I know that the code makes it look like each s-g element might map somewhere entirely different from the previous one, but we no longer support that mode of operation. Each VBD now always maps onto a single, entire block device or partition.

 -- Keir


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