R help - Jul 2005 - CPU Usage with R 2.1.0 in Windows

Hi,

I'm using a fairly simple HP Compaq desktop PC running Windows 2K.  When
running a large process in R, the process "RGUI.exe" will never exceed
50%
of the CPU usage.

The program used to be able to use more of the computer, but does not now.
I don't believe this is a multiple processor machine.

Can anyone give any advice on how to solve the problem?  

Thanks,

Michael Greene

Product Management
Plymouth Rock Assurance Corp
617-951-1682

Dear Michael:

Why is it a problem that R is not using more CPU space than it seems to
need? 

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Greene, Michael
Sent: Tuesday, July 19, 2005 2:29 PM
To: 'R-help at lists.R-project.org'
Subject: [R] CPU Usage with R 2.1.0 in Windows


Hi,

I'm using a fairly simple HP Compaq desktop PC running Windows 2K.  When
running a large process in R, the process "RGUI.exe" will never exceed
50% of the CPU usage.

The program used to be able to use more of the computer, but does not
now.
I don't believe this is a multiple processor machine.

Can anyone give any advice on how to solve the problem?  

Thanks,

Michael Greene

Product Management
Plymouth Rock Assurance Corp
617-951-1682

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html

Dnia 2005-07-19 20:28, Uytkownik Greene, Michael napisa:
> Hi,
> 
> I'm using a fairly simple HP Compaq desktop PC running Windows 2K. 
When
> running a large process in R, the process "RGUI.exe" will never
exceed 50%
> of the CPU usage.
If you have hyperthreading, R catches only one virtual processor (from
two available), being not able to exceed half of total power (100% of
one only). If you want to use full power, you should turn hyperthreading
off, if your BIOS supports such option.

Regards,

-- 
Lukasz Komsta
Department of Medicinal Chemistry
Medical University of Lublin
6 Chodzki, 20-093 Lublin, Poland
Fax +48 81 7425165

If you set the affinity of the R process to processor 0, you can run another (R
or other) process with affinity set to processor 1 and get 100% usage.
Most applications can't take advantage of hyperthreading (or
multiprocessors), since they have to be specially written to do so.

It seems that parts of Windows are single threaded, though, so, for example,
starting up another instance of Excel when one is already using all of a
'processor' can take a very long time, but if the processes are already
started, you can take advantage of the gross parallelism.

David L. Reiner
 
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-
> bounces at stat.math.ethz.ch] On Behalf Of Prof Brian Ripley
> Sent: Wednesday, July 20, 2005 3:12 AM
> To: Lukasz Komsta
> Cc: Greene, Michael; 'R-help at lists.R-project.org'
> Subject: Re: [R] CPU Usage with R 2.1.0 in Windows
> 
> It probably is not a problem to leave hyperthreading on: we found little
> performance difference on a P4 either way.
> 
> The Windows task manager is misleading, as `50%' is about as much as a
> P4-class processor with hyperthreading can actually deliver.
> 
> On Tue, 19 Jul 2005, Lukasz Komsta wrote:
> 
> > Dnia 2005-07-19 20:28, U????ytkownik Greene, Michael napisa????:
> >> Hi,> > I'm using a fairly simple HP Compaq desktop PC
running Windows
> 2K.  When> running a large process in R, the process
"RGUI.exe" will never
> exceed 50%> of the CPU usage.
> > If you have hyperthreading, R catches only one virtual processor
> (fromtwo available), being not able to exceed half of total power (100%
> ofone only). If you want to use full power, you should turn
> hyperthreadingoff, if your BIOS supports such option.
> > Regards,
> > -- Lukasz KomstaDepartment of Medicinal ChemistryMedical University of
> Lublin6 Chodzki, 20-093 Lublin, PolandFax +48 81 7425165
> > ______________________________________________R-help at
stat.math.ethz.ch
> mailing listhttps://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the
> posting guide! http://www.R-project.org/posting-guide.html
> >
> 
> --
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595