Big Calculations (was [Wien] Allocation error 494)

[Fred Nastos]

On February 22, 2005 08:49 am, L. D. Marks wrote:
> 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?

I heard back from the group I helped compile the code, and they
too have problems with the mpi runs.  As far as I know the code
compiles cleanly, but fails on execution (sorry, I have no more info).

Can you tell us the problem you encountered?

Thanks.

> 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
> > >
> > > _______________________________________________
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> >
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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
> -----------------------------------------------
>
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