Re: [AMBER] running simulation using increased number of cores

From: onetwo <twoone21.rediffmail.com>
Date: 15 Sep 2013 05:21:18 -0000

Dear Jason,



Thanks a lot for the reply.



I am using SANDER program for MD simulation. Regarding pmemd.mpi, i have never used it.

If sander and pmemd works the same way ?

Also if all the nodes have been interconnected, i will ask the vendor about it. Or if u have

can suggest how to find it out, it will be very helpful.



Thanks again.



Regards



On Sat, 14 Sep 2013 19:25:47 +0530 wrote

>On Sat, Sep 14, 2013 at 12:13 AM, onetwo wrote:







> Dear All,



>



>



>



> We have just installed RACK server in our lab, in which we have installed



> AMBER software in



>



> parallel. Server shows that it has 160 cores. When I run simulation job, I



> give np 160,



>



> equilibration job crashed. Then I tried using np 8, then it worked, then



> again I increased np to



>



> 32, it is running fine, but for 4ns production run for 321 amino acid, it



> is taking 72 hours to



>



> finish. When I used to run it on 8 cores on our previous workstation, it



> used to take same time.



>



> I tried on server np 80 also, still it shows more than 70 hours to finish.



>







A couple comments here. First, 'Amber' is a suite of programs, not a



single one. You need to tell us _which_ program you were using.



 Typically, pmemd.MPI gives better parallel scaling than sander.MPI (and it



gives better single-processor performance, as well). If you are not



using pmemd.MPI, you should start using that program instead.







Second, the interconnect between the nodes is very important -- unless you



have very fast infiniband, you will not be able to use multiple nodes (as



you've seen in the lack of speed-up).











>



>



> Please suggest, if I am missing something. and how to utilize all the



> cores for faster simulation



>







You may not be able to use all cores to speed up your simulation. This



will be true of all MD codes.







HTH,



Jason







-- 
Jason M. Swails
BioMaPS,
Rutgers University
Postdoctoral Researcher
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Received on Sat Sep 14 2013 - 22:30:02 PDT
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