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SubjectRe: IPv4 kernel messages

On Tue, 8 Sep 1998, Jamie Lokier wrote:

> Really, the right MMX checksum on the P5 should max out the memory
> busses. The overhead would be in the FPU context save/restore and
> switching to MMX mode.

hm, nope. Even on the PII i can barely make it a win. The problem is that
to generate IP checksums we have to do addition with carry - on the MMX
engine which has no carry, no flags and no branch instructions and no
effective ways of mixing integer and MMX instructions. Thus my code is
quite tricky and it saturates the PII completely so i'm not surprised at
all that it does not play well on a P5.

-- mingo


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