[R] CPU Usage with R 2.1.0 in Windows (and with R 2.3.1)

[Duncan Murdoch]

Markus Preisetanz wrote:
> ... I have exactly the same issue with R 2.3.1 . The Question is: Why is R unable to take more CPU space to make the calculation process go faster?
>  
> In my case no hardisk nor any network device is involved (data in RAM, 600 of 1024 MB filled) - and the CPU usage of the rgui-process does not exceed 50%.
>  
> Has anybody an idea? Is there a setting a can change?
>   
You are probably on a dual core or hyperthreaded machine.  R does almost 
all of its work in one thread, so it will max out the usage on one cpu, 
but not more than one.

If you are on a hyperthreaded machine, you can disable hyperthreading 
and the report should show 100% usage, but that doesn't mean things will 
be going twice as fast.  (I have heard that hyperthreading does slow 
down some computations, so turning it off might be a good idea, but I 
have never done the measurements myself.)

Duncan Murdoch
>  
> Sincerely, Markus
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> From: Doran, Harold <HDoran_at_air.org <mailto:HDoran_at_air.org?Subject=Re:%20%5BR%5D%20CPU%20Usage%20with%20R%202.1.0%20in%20Windows> > 
> Date: Wed 20 Jul 2005 - 04:59:34 EST
>
>
>
> 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 
>
>
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