Big Calculations (was [Wien] Allocation error 494)

[L. D. Marks]

To expand this subject slightly, has anyone worked out how to run really
big calculations on an Intel architecture in finite time? I've compiled
the mpi versions (thanks to Fred Nastos for the library structure) but in
some preliminary tests ran into some problems with mpirun which I have not
had time to solve. Is it worth the effort to try and solve the issues?

N.B., this would be for calculations which even with RKMAX=4.5 are taking
about 1.5G so an adequate calculation would be >> 2G.

N.N.B., it might be necessary to modify lapw1 to stick some of the huge
arrays on disk, e.g. using mmap calls.

On Tue, 22 Feb 2005, Michael Gurnett wrote:

> As far as I know, unless your running on a 64 bit machine, the most the
> operating system can allocate in a single chunk is 2GB.
>
> Michael
>
>
> ----- Original Message -----
> From: "Rebecca Nicholls" <rebecca.nicholls at st-catherines.oxford.ac.uk>
> To: <wien at zeus.theochem.tuwien.ac.at>
> Sent: Tuesday, February 22, 2005 1:59 PM
> Subject: [Wien] Allocation error 494
>
>
> >
> > hello everyone
> >
> > I was wondering if anyone had ever had trouble with allocation
> > errors on a 4G machine.  I sucessfully got a large job to start
> > on a 2G machine, using 1.5G RAM and 1G swap.  When I try to run
> > this same job on a 4G machine, I get allocation errors.  It seems
> > I'm having trouble using more than 2G out of the 4G of ram, and
> > the program is not using any swap.
> >
> > I've changed the stacksize to unlimited:
> >
> > cputime         unlimited
> > filesize        unlimited
> > datasize        unlimited
> > stacksize       unlimited
> > coredumpsize    0 kbytes
> > memoryuse       unlimited
> > vmemoryuse      unlimited
> > descriptors     1024
> > memorylocked    unlimited
> > maxproc         7168
> >
> > The 2G machine is a dual-processor (although I was only running
> > the job on one processor) Xeon 2.2Gz running red hat linux (kernel
> > 2.4.18-3smp).
> >
> > The 4G machine is a pentium 4 running suse (kernal 2.4.21-260-smp4G).
> >
> > Thanks a lot
> > Best wishes
> >
> > Rebecca
> >
> > _______________________________________________
> > Wien mailing list
> > Wien at zeus.theochem.tuwien.ac.at
> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> >
> >
>
>
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
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>

-----------------------------------------------
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60201, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L - marks @ northwestern . edu
http://www.numis.northwestern.edu
-----------------------------------------------