>> >         2) We either need huge descriptors or some chaining
>mechanism to
>> >         handle scatter-gather.
>> >
>>
>> Or, my preference, have a small sglist in the descriptor;
>
>
>Define "small" ;)
>
>There a certainly patterns that cannot/will-not take advantage of SG
>(for instance, your typical network rx path), and therefore the sg
>entries are wasted in some cases.  Since they need to be (IMHO) u64,
>they suck down at least 8 bytes a piece.  Because of this I elected to
>use the model of one pointer per descriptor, with an external
descriptor
>for SG.  What are your thoughts on this?

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.

-------------------------------------------------------------------------
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