Re: [patches] [PATCH] [8/35] x86_64: a memcpy that tries toreducecache pressure

From: Jan Beulich
Date: Mon Apr 30 2007 - 03:26:03 EST


>+ testb $8, %dxl /* rdx is 3,5,6,7,9..15 */

Could you use the more conventional name %dl (or whatever is being meant)
here?

>+.L42:
>+ prefetchnta 128(%rsi)

I think I commented similarly on a previous version of the patch: This will
- result in still bringing the first 128 bytes into the cache
- prevent caching of memory beyond the buffer being dealt with

>+ sfence

Similarly, I continue to believe this is wrong here (again I commented before
that this is likely unnecessary, or if at all, it should be an lfence).

>+ orl %edx, %edx

Operations of this type generally should use 'test', not 'or' or 'and'.

Jan


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