On 07/12/17 12:40, Sitangshu Bhattacharya wrote: > As per my experience, QE/VASP or any other such computations which uses > openmpi supports 2^n core processors.
Just to be clear: QE can use any number of CPUs, being a power of 2 or not does not matter. kind regards This is actually total number of > core per physical processor multiplied by 2 (hyperthreaded), check by > typing "htop" in your terminal. You may try locating the wall time > results done at different no. of cores for your computations. The > results might be a bit faster if you use 32 instead of 40 (and so on) > and divide them into pools. Please note that inter-node communications > in PWSCF is the main bottleneck and depends on the 100GBpS or more > connectivity switch. Eagerly waiting for this to be taken care by QE > experts!. Image parallelization is supported by the Ph.x code, however > collecting the results is a bit tricky if you are doing 2nd or 3rd order > corrections. Parallelizing diagonalization technique make my computation > a bit slower, probably due to the the less no. of atoms involved or so. > Check with -np 2 only, first on a simple structure like Si and then > increase this no. to see if this is taking more/less time. You will get > an idea atleast.. > > Regards > > On Thu, Dec 7, 2017 at 2:50 PM, Amar Singh > <[email protected] <mailto:[email protected]>> > wrote: > > Dear Dr. Bhattacharya, > Thanks for the link. Though, being very naïve to such computation, > I am not able to figure out the best possible set of parameters I > should start with. Would be thankful if you can suggest some typical > values for -np, -ni, -nk, -nt and -nd for the system with 40 > processors and 256 GB RAM. > thanks > Amar > > _______________________________________________ > Pw_forum mailing list > [email protected] <mailto:[email protected]> > http://pwscf.org/mailman/listinfo/pw_forum > <http://pwscf.org/mailman/listinfo/pw_forum> > > > > > -- > ********************************************** > Sitangshu Bhattacharya (সিতাংশু ভট্টাচার্য), Ph.D > Assistant Professor, > Room No. 2221, CC-1, > Nanoscale Electro-Thermal Laboratory, > Department of Electrical and Communication Engineering, > Indian Institute of Information Technology-Allahabad > Uttar Pradesh 211 012 > India > Telephone: 91-532-2922000 Extn.: 2131 > Web-page: http://profile.iiita.ac.in/sitangshu/ > Institute: http://www.iiita.ac.in/ > > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- Lorenzo Paulatto - Paris _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
