Re: efficient copy_to_user and copy_from_user routines in Linux Kernel

Date: Tue Jun 25 2002 - 12:43:23 EST


> I changed tcp to use a different copy if either source or dest were
> not eight-byte aligned, and found that the resulting improvement
> across a mixed networking load was only 1%. Your numbers are higher,
> so perhaps there are different alignments in the mix...

Did you look at sender or changed both of the functions?

After that accident TCP was changed and it does not use copy_from_user more,
it does copy_and_csum even when no checksum is required. So, his results
on sender side (except for strange anomaly at msg size 8K) just confirm
nil effect of copy_from_user.

What's about copy_to_user, we forgot about this at all,
worrying mostly about sender side. :-)

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This archive was generated by hypermail 2b29 : Sun Jun 30 2002 - 22:00:09 EST