[R-SIG-Mac] Performance Issues.

[Simon Urbanek]

Byron,

On May 16, 2006, at 8:34 PM, Byron Ellis wrote:

> Apparently somebody was having some performance issues
>
> http://sekhon.berkeley.edu/macosx/
>
> fortunately, it got dugg and someone fixed it for us
>
> http://ridiculousfish.com/blog/archives/2006/05/16/36/
>
> In an unsurprising turn of events it turns out to be malloc's fault.
> It also looks like the build isn't against an optimized BLAS?
>

We had a discussion about this earlier, it started with
https://stat.ethz.ch/pipermail/r-sig-mac/2006-March/002722.html

What it boils down to is that ptATLAS can give you a good speed-up,  
but it can also screw you up by calling malloc/free all the time - it  
depends on the task. For single core CPUs it's definitely better to  
use R's own BLAS. For Core Duos it depends on the size of the problem  
- for bigger problems ptATLAS is better, for smaller problems  
internal BLAS may be better.

In a quiet minute I'll try to run our benchmarks with Lea's allocator  
and see if it would make sense to use it for OS X.

Thanks,
Simon