[R] question about performance on different operating systems

[Matthew Norton]

On Wednesday 12 December 2001 15:29, Prof Brian Ripley wrote:
> On Wed, 12 Dec 2001, Matthew Norton wrote:
> > I have  a quick question for the gang.
> >
> > I'm running a batch of simulations on a number of different computers,
> > and have noticed that certain systems seem to run much more slowly than
> > others. A rough calculation leads me to think that R for the Macintosh is
> > running at _least_ 10 times more slowly than under linux.
> >
> > To give you an idea, to run a small number of simulations takes around 80
> > seconds on my laptop (running Debian linux, 200MHz processor, 112 megs
> > RAM) while the same batch takes upwards of 10 minutes on a powermacintosh
> > G4 (350MHz and 128 megs of RAM).
> >
> > Out of curiosity, is this unexpected, or can that sort of performance hit
> > be normal when changing operating systems.
> >
> > Matthew Norton
> > Dept. Biological Sciences
> > Universite de Montreal
> > Canada.
> >
> > p.s. I'll run the same check on my windows desktop at home, and let you
> > all know its speed.
>
> In my experience R under Windows is about 10-20% slower than Linux on the
> same box. We know about 5% of the difference (polling vs interrupts) and
> th rest seems to be down to compiler quality (yes, they are both i686 gcc,
> but still not too similar compilers often giving different answers).
>
> A lot of this is down to the performance of the memory manager, which R
> uses hard, and we had to replace on Windows at 1.2.0 not to take a big hit
> (ca 3x).  Is this classic MacOS or MacOS X, and if the latter, which port?


This is MacOS 9.1. As to the windows machine, it did seem a little more 
sluggish than my linux machine, but it is much more powerful and thus a 
little perfomance hit is unnoticeable to me.  I'll test out the speed of the 
windows machine at home this evening, and let you know about relative 
performance (should you care to; if not, feel free to aggresively delete the 
email).

Matthew
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