Re: interesting paper at usenix...

[Matt Fleming <mjf%NetBSD.org@localhost>]

On Wed, Jun 25, 2008 at 02:10:05PM -0400, Perry E. Metzger wrote:
> 
> There's a paper on TCP receive path being presented today. Dunno how I
> feel about the ideas described but they are claiming very large
> speedups in Linux. It might be worth looking at whether the ideas are
> good and can be applied to NetBSD's stack.
> 
> http://www.usenix.org/events/usenix08/tech/full_papers/menon/menon_html/index.html
> 
> 

It is an interesting paper, though I'm a little skeptical that they
achieve the speed up they claim.

I don't think packet aggregation is feasible for NetBSD in general
because of this statement,

"Packet aggregation is done only for valid TCP packets, i.e., those with
a valid TCP and IP checksum. We verify only the IP checksum field of the
network TCP packet before it is used for aggregation. For the TCP
checksum, we assume the common case that the NIC supports checksum
offloading, and has validated the TCP checksum. This is because
verifying the TCP checksum in software would make the aggregation
expensive."

Matt