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From: "Sam Leffler" <sam@errno.com>
To: "Mike Silbersack" <silby@silby.com>,
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Date: Tue, 25 Mar 2003 17:54:55 -0800
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Subject: Re: cvs commit: src/sys/conf options src/sys/netinet ip_output.c
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> I've been pondering where the tradeoff between avoiding memory copies and
> doing excessive scatter / gather DMA lies.  Perhaps we should be
> defragmenting any chain over a certain amount of length, no matter the
> limit imposed by the card.  This sounds like a Terry question. :)

I hit this in fast ipsec.  I do "agressive coalescing" when creating
writable mbuf chains on output.  It's a big win for various things.  Full
results will be in the paper I'm writing for bsdcon.

    Sam