Re: Big git diff speedup by avoiding x86 "fast string" memcmp

[J. R. Okajima]

Nick Piggin:
> It's not scaling but just single threaded performance. gcc turns memcmp
> into rep cmp, which has quite a long latency, so it's not appripriate
> for short strings.

Honestly speaking I doubt how this 'long *' approach is effective
(Of course it never means that your result (by 'char *') is doubtful).
But is the "rep cmp has quite a long latency" issue generic for all x86
architecture, or Westmere system specific?


J. R. Okajima
--
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/