From hin-tak.leung at cimr.cam.ac.uk  Thu Oct 13 16:07:29 2005
From: hin-tak.leung at cimr.cam.ac.uk (Hin-Tak Leung)
Date: Thu, 13 Oct 2005 15:07:29 +0100
Subject: [Rd] R, Wine, and multi-threadedness.
In-Reply-To: <434E506F.3080504@cimr.cam.ac.uk>
References: <434E321B.3040603@cimr.cam.ac.uk>
	<Pine.LNX.4.61.0510131158100.4655@gannet.stats>
	<434E506F.3080504@cimr.cam.ac.uk>
Message-ID: <434E6A21.1010800@cimr.cam.ac.uk>

Hin-Tak Leung wrote:
> Prof Brian Ripley wrote:
> 
>> On Thu, 13 Oct 2005, Hin-Tak Leung wrote:
<snipped>
>>> (2) The interesting question: As I understand it (could be wrong),
>>> R Win32 is (partly) multi-threaded, and the native linux R is not.
>>> Is is possible to have better performance or CPU utilisation
>>> on multi-CPU systems running Win32 R under Wine rather than natively?
>>> At least on certain specific application areas?
>>
>>
>>
>> Rterm.exe is multithreaded, but the second thread is only used for 
>> input. RGui.exe is singlethreaded.  As R for Windows uses a DLL it is 
>> about the same speed (running Windows natively on the same hardware) 
>> as R under ix86 Linux using a shared library, and that is appreciably 
>> slower than R under ix86 Linux without (see the R-admin manual).  R 
>> under Linux can make use of a multithreaded BLAS, but I know of none 
>> available for Windows.
> 
> 
> Is the Intel MKL not available form Windows? Somewhat surprising...

Sorry to reply to my own post.

Actually, FAQ 8.2 for r-on-windows and the netlib FAQ:
http://cran.r-project.org/bin/windows/base/rw-FAQ.html#Can-I-use-a-fast-BLAS_003f
http://www.netlib.org/blas/faq.html#9

seems to suggest otherwise - from what it says, (1) the BLAS dll can be 
conveniently replaced without recompiling, (2) most vendor BLAS 
implementations are multi-threaded. In fact the Atlas implementation
is explicitly named in both places.

Now, the interesting questions are: (1) is Atlas multi-threaded on 
*every* platform, or more specifically, on Windows?, (2) Can wine
use the atlas dll under x86 linux?

Hin-Tak Leung



[Rd] R, Wine, and multi-threadedness.
Hin-Tak Leung