[PATCH][X86_64] Set bit_Fast_Unaligned_Load for Excavator family CPU's

[Ondřej Bílka]

On Wed, Dec 16, 2015 at 10:03:25AM +0000, Pawar, Amit wrote:
> For latest AMD Excavator family 0x15h CPU's, it is found that by running GLIBC benchtest SSE2_Unaligned based implementations are performing faster compare to SSE2 based implementations for routines mentioned below. Based on this observation bit_Fast_Unaligned_Load flag is set for Excavator family CPU's. This makes SSE2_Unaligned implementations as default for these routines.
> 
> Routines: strcmp, strcat, strncat, stpcpy, stpncpy, strcpy, strncpy and strstr. 
> 
> Is attached patch OK for trunk ?
> 
Should be ok, while benchtests are as bad as random noise for measuring
performance I know that now amd processors are not optimized at all, I
had some patches for to improve that situation that I could ping 11th
time.

Particulary unaligned path is also better in bulldozer and these
routines are good only for older cpus of phemonII era. I recalled there
are some tweaks that I had for bulldozer but I don't remember these.