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RE: [Xen-devel] Add multi-page shared ring support toxen-blkfront/back

To: "Paul Durrant" <paul.durrant@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] Add multi-page shared ring support toxen-blkfront/back
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Wed, 13 Jan 2010 07:58:47 +1100
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Thread-topic: [Xen-devel] Add multi-page shared ring support toxen-blkfront/back
> 
> Paul Durrant wrote:
> > These patches add support for multi-page shared rings to
xen-blkfront/back.
> > Shared rings must always be a power of 2 in size and so the size is
> controlled
> > by the new 'max_ring_page_order' module parameter of xen-blkback.
This
> defaults
> > to 0 so operationally there should be no difference with these
patches in
> place.
> > The maximum value of 'max_ring_page_order' is currently limited to 2
> > (i.e. 4 pages).
> > xen-blkfront will always use the largest shared ring size supported
by the
> back
> > end. To override this and continue to use a single page ring, as
before, set
> the
> > 'allow_multi_page_ring' module parameter to 0.
> >
> 
> I don't know why git-send-email seems to have sent my patch series
into
> a black hole. Here they are as attachments this time.
> 

I received the 1/2 and 2/2 emails containing the patches.

Is there any measurable performance increase with this update? I assume
it means that you can have more read/write operations on the ring at
once? What would be useful to me is larger read/write operations...

James

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