[Pw_forum] Computer cluster Parallel run:-Reg

[mohammed shambakey]

Hi Suresh

I'm new to Quantum_Espresso, but how many processes you specify when
running the command (the "-procs" option with "poe", the "-n or -np" with
"mpirun/mpiexec")? How many cores does your cluster support? Because I
don't think the "-ni and -nk" options will distribute the processes by
themselves.

Regards

On Tue, Aug 11, 2015 at 1:01 PM, Suresh A <suresh2007pgp19 at gmail.com> wrote:

> Respected Sir/Friends,
>                     I have formed a PC beowulf cluster (X86_64 old PC's
> made on 2007) and installed quantum espresso-5.2.0 in it. Now the cluster
> is running very slowly than the single core i5 processor, DDR3 RAM with
> 1600MHZ speed. The following is my observation in single core i5 processor
> and in beowulf cluster for the titanium dioxide supercell of size 2x2x1.
> One more thing is, in cluster every node has 2GB DDR2 RAM with speed 667
> MHZ. for i5 processor 8GB with 1600 HZ.
>
> total cpu time spent upto now is    408.7 secs   (for  i5 CPU having
> 1600MHZ)
>
> total cpu time spent upto now is    it is keepon running more than 1 hour
> (for one single processor in PC cluster)
>
> total cpu time spent upto now is    1402 secs ( for -ni 10 -nk 10 in PC
> cluster)
>
>
>
> Is this due to RAM speed, size or anything else?
>
> Looking forward to your valuable suggestions
>
>                   With Regards,
> A.Suresh,
> Research Scholar,
> Madurai Kamaraj University,
> Madurai.
>
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-- 
Mohammed
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