On Mon, 2007-08-20 at 17:12 +0300, Avi Kivity wrote:
> Dor Laor wrote:
> > Using Rusty's code there is no waste.
> > Each descriptor has a flag (head|next). Next flag stands for pointer to
> > the
> > next descriptor with u32 next index. So the waste is 4 bytes.
> > Sg descriptors are chained on the same descriptor ring.
> >   
> 
> Block I/O can easily require 256 sglist entries, eating up your ring.

Absolutely; I think we'd want this variable sized, rather than a single
page as the current implementation does for no really sound reason.

That said, I don't have a problem with Avi's out-of-band mechanism.  A
"DMA" hypercall can follow that almost as easily, and it does give that
nice "fixed number of slots" effect.

Cheers,
Rusty.


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/
_______________________________________________
kvm-devel mailing list
kvm-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/kvm-devel

Reply via email to