Re: [rc4-amd64] RC4 optimized for AMD64

[dean gaudet]

On Tue, 2 Nov 2004, Denis Vlasenko wrote:

> On Monday 01 November 2004 22:44, dean gaudet wrote:
> > note that 
> > p4 would prefer "sub $1, %r11b" here instead of dec... but the difference 
> > is likely minimal.
> 
> p4 is not the only x86 CPU on the planet. Why should I use
> longer instruction then?

you're asking about spending one byte?  one byte extra for code which 
could perform better on more CPUs?

i could equally well say "k8 is not the only x86-64 cpu on the planet".

i really don't care whether this change is made or not, i only mentioned a 
general perf rule.

go ahead and use -Os for the rest of the kernel if you're worried about 
size, it'll likely go faster.  but spending 1 byte in code which is perf 
critical is nothing.

-dean
-
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/