R help - Apr 2002 - Multithreading

Hi !

I wonder if the R application is capable of utilizing more than one CPU. I
need to know since we run it on a SunFire 3800 with 8 750 USIII cpu:s and on
a E420R with 4 USII cpu:s and we don't feel like we get the performance we
could expect.

I've seen some old discussions claiming that it isn't.

With kind regards

Lennart Araskoug
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Lennart.Araskoug at astrazeneca.com writes:
> Hi !
> 
> I wonder if the R application is capable of utilizing more than one CPU. I
> need to know since we run it on a SunFire 3800 with 8 750 USIII cpu:s and
on
> a E420R with 4 USII cpu:s and we don't feel like we get the performance
we
> could expect.
> 
> I've seen some old discussions claiming that it isn't.
It isn't ... yet. Duncan and Luke hope to get it going for 1.6.0.

You can in principle link against a threaded ATLAS library (although
there are known signal handling problems with that) and get multi-CPU
numerics performance. And of course run multiple instances of R.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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> From: Peter Dalgaard BSA [mailto:p.dalgaard at biostat.ku.dk]
> 
> Lennart.Araskoug at astrazeneca.com writes:
> 
> > Hi !
> > 
> > I wonder if the R application is capable of utilizing more 
> than one CPU. I
> > need to know since we run it on a SunFire 3800 with 8 750 
> USIII cpu:s and on
> > a E420R with 4 USII cpu:s and we don't feel like we get the 
> performance we
> > could expect.
> > 
> > I've seen some old discussions claiming that it isn't.
> 
> It isn't ... yet. Duncan and Luke hope to get it going for 1.6.0.
> 
> You can in principle link against a threaded ATLAS library (although
> there are known signal handling problems with that) and get multi-CPU
> numerics performance. And of course run multiple instances of R.
When I was fooling with ATLAS and MKL a while ago, I found that when I use
the threaded ATLAS, the elapsed time is actually longer than ATLAS w/o
threads.  MKL, OTOH, did provide the almost doubled speed expected on the
dual CPU box.  (Mandrake 7.1/R1.4.1/P3-866 Xeon).

Andy

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