Re: [PATCH] net: optimise inet_proto_csum_replace4()

From: David Miller
Date: Fri Sep 26 2014 - 16:14:53 EST

From: Christophe Leroy <christophe.leroy@xxxxxx>
Date: Tue, 23 Sep 2014 10:54:37 +0200 (CEST)

> csum_partial() is a generic function which is not optimised for small fixed
> length calculations, and its use requires to store "from" and "to" values in
> memory while we already have them available in registers. This also has impact,
> especially on RISC processors. In the same spirit as the change done by
> Eric Dumazet on csum_replace2(), this patch rewrites inet_proto_csum_replace4()
> taking into account RFC1624.
> I spotted during a NATted tcp transfert that csum_partial() is one of top 5
> consuming functions (around 8%), and the second user of csum_partial() is
> inet_proto_csum_replace4().
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>

Also applied, thanks Christophe.
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