Re: 5.1 a little slower than 5.0.2

[Asko Kauppi <asko.kauppi@...>]

If this kind of performance gains (magnitude 10%!) are easily gained, 
even if they're platform specific, I would like them to be used out of 
the box. :)  The reason?  People will be comparing Lua with other 
scripting languages (s.a. Python) in real world situations, and most 
likely using x86 platforms doing that.

-ak

25.9.2004 kello 19:03, Mike Pall kirjoitti:

 Hi,
> Following up to myself:
> >   A combined inline assembler replacement may speed up the code quite
> >   a bit. Anyone know what the fastest way to determine whether a 
> > double
> >   fits into an int is on x86?
>
> Well, it's simpler than I thought: the FPU already stores overflow and
> precision loss bits in the status word. You just have to check them 
> after
> the fistpl instruction.
>
> >                 -O     -O2    -O3 -fomit-frame-pointer
> > lua-5.0.2       3.30   3.40   3.60
> > lua-5.1-work0   3.72   4.30   3.44
> > lua-5.1-work2   4.03   4.18   3.50
>
> Trying the same tests with the appended patch:
>
> lua-5.1-work2a    3.82   4.07   3.28
>
> Looks better now.
>
> There are plenty more optimization opportunities in ltable.c and lvm.c,
> but I'll leave that to someone with an immediate need. Dito for the
> conversion of the GCC assembler macros to MSVC syntax.
>
> Bye,
>      Mike
> <getnum.patch>