Re: Possible improvement to pipe throughput

Matthias Urlichs (
Fri, 27 Sep 1996 12:54:25 +0100

In, article <>,
"David S. Miller" <> writes:
> Implementing this for the pipe case might be useful, it will give us a
> better idea how difficult page flipping in the networking layer will
> be for us to implement.
Damn difficult.

The problem is, we need to get the data _after_ all the headers into a
specific position. This would mean that the code which reads the IP frame
from the card only reads the IP header, then the TCP code reads the TCP
header and figures out where on the flip-out page to put the data. After
that, you check the TCP checksum, and if it doesn't match you undo the
effects of all of the above. :-/

This is certainly possible. Whether it's a good idea to totally rewrite
the IP stack to do it is another question entirely, and I for one would
answer it with a resounding "You must be crazy".

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