Re: [PATCH] net: optimise csum_replace4()

From: Eric Dumazet
Date: Tue Sep 23 2014 - 07:08:25 EST


On Tue, 2014-09-23 at 10:54 +0200, Christophe Leroy wrote:
> 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().
>
> I have proposed the same modification to inet_proto_csum_replace4() in another
> patch.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>

Thanks Christophe, this looks good to me.

Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>


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