Dear Ren, there is at moment a big effort done in this direction from the computational center in Irland (ICHEC) and the developers of QE-GIPAW (see http://qe-forge.org/projects/qe-gipaw/).
bests Layla 2011/11/18 Ren PJ <renpj at dicp.ac.cn> > On Fri, 18 Nov 2011 10:54:56 +0100 > > > Dear Pengju Ren, > > when you increase the numebr of processors you increase the > > available computing power, but also the amount of communications on > > the network connectign those nodes. As the network has a finite > > speed, there will be a point where the code looses more time > > exchanging information between the cpus than doing any calculation. > > > > Possible solutions: > > 1. use fewer cpus (between 8 and 160 there is plenty of space) > > 2. try with a different number of pools (you could try > > nkpoints*ncores_per_node) > > 3. buy some faster network hardware > > > > best regards > > > > Dear Lorenzo Paulatto, > Thanks for your kind answer. > When I ran pw.x with 160 cpus it was about 10 times faster than with 8 > cpus, I think the parallel efficiency is reasonable. So does gipaw.x > need more communications between nodes than pw.x? Maybe the gipaw code > could be improved by reducing the communication frequency. > > Best Wishes > > ================================================ > ??? > Pengju Ren > renpj at dicp.ac.cn > State Key Laboratory of Catalysis, > Dalian Institute of Chemical Physics, > Chinese Academy of Sciences > 457 zhongshan Road, Dalian, 116023, P.R. China > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20111118/fc1feac2/attachment.htm
