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SubjectRe: Speed of memcpy, csum_partial and csum_partial_copy
> My point is that you may be able to make memcpy, csum_partial and
> csum_partial_copy faster by preloading the data into the cache -- just
> touch every 32nd byte before the csum+copy loop.

Its questionable that is worth while as the csum stuff is almost always
coming to or from cache, L2 cache at least.

> My other point is that csum_partial_copy looks like it could run 33%
> faster, when everything is in the CPU cache, by rearranging the
> instructions in the loop to pair fully -- I think that adcl can pair but
> only in the U pipe. (I could be wrong about this. If adcl can pair
> anywhere, there are still write-then-read dependencies that prevent
> pairing in that code).

Several people have sped the checksum/copy code up over time. If you can
speed it further then you will be number 4, and since the performance of
these routines is very critical then the patches will be welcome.


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