Checksum/copy (was: Re: cvs commit: src/sys/netinet ip_output.c)

From: Nate Lawson <>
Date: Wed, 26 Mar 2003 13:50:27 -0800 (PST)
On Tue, 25 Mar 2003, Mike Silbersack wrote:
> On Tue, 25 Mar 2003, Doug Ambrisko wrote:
> > Maybe an extent count could be used that said how long the chain is.
> >
> > As Sam mentioned having little things scattered around is not good thing.
> > Memory and CPU can be a lot faster then the I/O bus.
> >
> > Doug A.
> I think we could inexpensively walk the mbuf chain at the end of ip_output
> and do the counting there.  Realistically, the same chain will be rewalked
> very soon afterword when the network card tries to set up the DMA
> transfers / etc.

I don't want to hijack the thread too much, but has thought gone into a
combined checksum and copy function?  The first mention I can remember of
this is in RFC 817 p. 19-20.

Received on Wed Mar 26 2003 - 13:50:27 UTC