Re: [PATCH RFC] [X86] performance improvement for memcpy_64.S byfast string.

[H. Peter Anvin]

On 11/11/2009 12:34 PM, Cyrill Gorcunov wrote:
>                        			memcpy_orig	memcpy_new
> TPT: Len 1024, alignment  8/ 0:		490		570
> TPT: Len 2048, alignment  8/ 0:		826		329
> TPT: Len 3072, alignment  8/ 0:		441		464
> TPT: Len 4096, alignment  8/ 0:		579		596
> TPT: Len 5120, alignment  8/ 0:		723		729
> TPT: Len 6144, alignment  8/ 0:		859		861
> TPT: Len 7168, alignment  8/ 0:		996		994
> TPT: Len 8192, alignment  8/ 0:		1165		1127
> TPT: Len 9216, alignment  8/ 0:		1273		1260
> TPT: Len 10240, alignment  8/ 0:	1402		1395
> TPT: Len 11264, alignment  8/ 0:	1543		1525
> TPT: Len 12288, alignment  8/ 0:	1682		1659
> TPT: Len 13312, alignment  8/ 0:	1869		1815
> TPT: Len 14336, alignment  8/ 0:	1982		1951
> TPT: Len 15360, alignment  8/ 0:	2185		2110
> 
> I've run this test a few times and results almost the same,
> with alignment 1024, 3072, 4096, 5120, 6144, new version a bit slowly.
> 

Was the result for 2048 consistent (it seems odd in the extreme)... the
discrepancy between this result and Ling's results bothers me; perhaps
the right answer is to leave the current code for Core2 and use new code
(with a lower than 1024 threshold?) for NHM and K8?

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/