Re: LuaJIT2 performance for number crunching

[KHMan <keinhong@...>]

On 2/17/2011 12:17 AM, Miles Bader wrote:
> KHMan writes:
> > > > Sorry to barge in, it is a worrying difference. One thing is bugging me:
> > > > Is the C code running SSE2? IIRC gcc -O2 does not normally enable SSE2.
> > >
> > > It will enable it by default when it thinks it's possible.
> >
> > But this is not standard behaviour. I haven't heard of such a change
> > in gcc default behaviour from the past few release notices. Would be
> > much obliged if you can correct me on this.
>
> It is on x86_64 systems, using the x86_64 abi; e.g.:

Okay, I do know the x86_64 ABI. You need SSE2 for that, no ifs or 
buts. I think that this:

    It will enable it by default when it thinks it's possible.

is pretty ambiguous (I did not think you meant 64-bit since it 
wasn't optional for the 64-bit ABI) and thus confused me.

Unfortunately, I did not detect in the discussion which ABI 
Francesco was using, or else I wasn't paying sufficient attention.

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia