Mala Anand wrote:
> Here is a 2.5.19 patch that improves the performance of IA32 copy_to_user
> and copy_from_user routines used by :
> (1) tcpip protocol stack
> (2) file systems
This came up about a year back when zerocopy networking was merged.
Intel boxes started running more slowly purely because of the 8+8
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...
One question: have you tested on other CPU types? This problem is
very specific to Intel hardware. On AMD, the eight-byte alignement
artifact does not exist at all. It could be that your patch is not
desirable on such CPUs?
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This archive was generated by hypermail 2b29 : Sun Jun 30 2002 - 22:00:09 EST