[Rd] Running R on dual/quad Opteron machines

[Thomas Lumley]

On Mon, 6 Mar 2006, Simone Giannerini wrote:

> On 3/6/06, Thomas Lumley <tlumley at u.washington.edu> wrote:
>> On Mon, 6 Mar 2006, Simone Giannerini wrote:
>>> The environment will probably be either Unix/Linux or Solaris and the
>>> amount of RAM will be 8-16Gb, depending on the number of processors.
>>> My main concerns are the following:
>>>
>>> 1. How much does R  benefit from passing from one processor to
>>> two/four processor machines? Consider that the typical intensive use
>>> of the server
>>> will be represented by simulation studies with many repeated loops.
>>
>> The typical way that R is used on multiprocessor systems is running more
>> than one program, rather than parallel processing. If four people are
>> using the computer or if one person splits 10,000 iterations of a
>> simulation into 4 sets of 2,500 you will be using all four processors.
>>
> Many thanks, if I have understood correctly, in this case I would need
> running four separate instances of R, since a single thread cannot
> exploit more than one cpu, am I correct?
>

You *can* exploit more than one CPU using eg the "snow" package, but it's 
often easier to just run multiple instances of R, and for a shared 
computing system there are often multiple people each running one instance 
of R.

 	-thomas