[Radiance-general] Mac OSX, xgrid and RADIANCE

[Gregory J. Ward]

Hi Thomas,

I hadn't realized that Mark Stock had finalized his new benchmark.   
It's really nice.

I gave it a try today, and also found my G5 running 10.4 to come up  
short in the tests.  I have a 1.8 GHz G5 PowerMac, which performed  
just slightly bettern than a 1.6 GHz P4-M running Linux and compiled  
with gcc 3.3.2 -O3.  (My copy was compiled with gcc 4.0.0 -O2.)   
What's even more surprising is that 1.5 GHz G4 laptop is about 13%  
faster than my G5, when by the clock it should be at least 17%  
slower!  I suspect there's something really wrong with gcc 4.0 on the  
G5, and since it's just come out, it hasn't been fixed.  Compiling  
with -ffast is not usually a good idea, as that's always broken  
things in the past, but you could try it just to see what happens.   
(I wouldn't trust it on any paying jobs, though.)  I might try -ffast- 
math tomorrow if I get time.

-Greg

> As a related note on OS X 10.4:
>
> I'm trying to get a bit of performance from my G5 iMac. Compiling the
> Radiance source is a matter of minutes. But when I try Mark's  
> benchmarks
> (http://mark.technolope.org/pages/rad_bench.html) the rpict time is  
> worse
> than his results for an 1.6 GHz P4-M.
>
> I thought a 2 GHz PowerPC would perform much better than that. I have
> only tested a few compiler optimizations so far but I don't think they
> will change that much any more. Apple ships gcc 4.0 as default  
> compiler
> for 10.4. Could this be the reason?
>
> What performance should I expect from the G5?
>
>
> Thomas
>