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runtime slow with vasp 5.2.11

Posted: Mon May 16, 2011 12:22 pm
by buudo
Dear all,
I compiled vasp 5.2.11 similar to version 5.2, but now the runtime went slow dramatically. It is runing on 12 cores like version 5.2 on 1 core. Does anybody know the reason for this behavior of the code ?
buudo

runtime slow with vasp 5.2.11

Posted: Mon May 16, 2011 4:32 pm
by alex
Please provide some more data to have a better comparison than "slower", e.g. version, runtime, number of cores, compiler version etc.

Thanks,

Alex

runtime slow with vasp 5.2.11

Posted: Wed May 25, 2011 4:29 pm
by sabbem
Assuming you calculate on a 12-core-per-socket machine, are you sure you used the latest MPI libraries? At least Intel MPI 3.x fails to recognize the 12 cores per socket, and identifies 8 physical cores and 4 'virtual' cores - which leads to an unfavorable 12 threads on 8 cores. No problems observed with MPI 4.0.