Agreed. Or use something like (in parallel_options, 1 k-point only, could be generalized)
set a=`grep -e "1:" .machines | grep -v lapw0 | cut -f 3 -d: | cut -c 1-2` setenv MKL_NUM_THREADS $a setenv OMP_NUM_THREADS $a or set a=`grep -e $HOSTNAME $PBS_NODEFILE | wc -l` My opinion is that this should be set at the OS level with MKL_NUM_THREADS etc set by msub/qsub or similar. I've seen problems due to other processes (not mine) using more threads than they should. On Tue, Mar 15, 2011 at 10:35 AM, Peter Blaha <pblaha at theochem.tuwien.ac.at> wrote: > Setting OMP_NUM_THREAD lets you select to use multithreading or not. > > A slight modification of our example script on the WIEN2k faq page > can even accounts for this and automatically span on eg. 8 core only > 4 mpi processes (when OMP_NUM_THREAD=2). > > > Am 15.03.2011 15:31, schrieb Laurence Marks: >> >> This is an informational report of an issue that can arise with Wien2k >> leading to poor performance. I came across it when experimenting with >> the "procs=XX" option in msub/qsub with XX=64 as an alternative to the >> more standard "nodes=X:ppn=Y". >> >> In an scf cycle lapwdm and (with the next release) mixer always use >> lapack routines (and maybe some others) which by default with mkl are >> multithreaded and use multiple cores. For a mpi run with lapw0: >> specified lapw0, lapw1 and lapw2 all use mpi. A issue can arise with >> msub/qsub (and perhaps other) if the number of cores mkl uses is >> larger than what has been allocated and there are other mpi tasks >> running on the same node. Then the performance of lapwdm can be bad; >> in one case rather than taking 30 seconds it took 14 minutes. >> >> I am not sure if this is something "fixable" in WIen2k, and there are >> ways in qsub/msub to avoid it using nodes=X:ppn=Y. However, procs=XX >> is "nice" as Wien2k in mpi does not really need factors of 2 >> cores/node (I've tested this) and can fit in the gaps. >> >> N.B., running without mpi and using nodes=X:ppn=1 could also run into >> the same problem. >> > > -- > > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?P.Blaha > -------------------------------------------------------------------------- > Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna > Phone: +43-1-58801-15671 ? ? ? ? ? ? FAX: +43-1-58801-15698 > Email: blaha at theochem.tuwien.ac.at ? ?WWW: > http://info.tuwien.ac.at/theochem/ > -------------------------------------------------------------------------- > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > -- Laurence Marks Department of Materials Science and Engineering MSE Rm 2036 Cook Hall 2220 N Campus Drive Northwestern University Evanston, IL 60208, USA Tel: (847) 491-3996 Fax: (847) 491-7820 email: L-marks at northwestern dot edu Web: www.numis.northwestern.edu Chair, Commission on Electron Crystallography of IUCR www.numis.northwestern.edu/ Electron crystallography is the branch of science that uses electron scattering and imaging to study the structure of matter.
