On Tue, 29 Jul 2008, lihm wrote: HL> Dear all,
dear haiming li, HL> I am a fresh user of PWscf. I run the parallel calculations to have a test. HL> A single process test is OK: HL> HL> PWSCF : 5m40.68s CPU time, 6m 0.14s wall time HL> HL> However, I found that the walltime is too long for parallel calculations: HL> HL> PWSCF : 1m 4.86s CPU time, 32m53.67s wall time HL> HL> I am sure that the CPU are not busy, or influenced by other jobs. yes, but what kind of a network do you have? please see the many discussions on efficient use of paralellism in QE calculations in the QE documentation (wiki!) and the mailing list archives. HL> The running command is: HL> HL> /usr/local/mpich/bin/mpirun -np 4 -machinefile nodelist /bin/pw.x < ZnO.scf.inp > ZnO.scf.out try adding -npools 4 after pw.x your system is small but has many k-points. that flag should enable parallelization over k-points which is less sensitive to high communication latencies and slow networks. the value of the 'disk_io' parameter can have an effect as well. cheers, axel. HL> My input file is HL> HL> &CONTROL HL> calculation = 'scf' , HL> restart_mode = 'from_scratch' , HL> outdir = './' , HL> wfcdir = '/tmp/' , HL> pseudo_dir = './' , HL> prefix = 'ZnO' , HL> disk_io = 'minimal' , HL> tstress = .true. , HL> tprnfor = .true. , HL> / HL> &SYSTEM HL> ibrav = 4, HL> celldm(1) = 6.213, HL> celldm(3) = 1.610, HL> nat = 4, HL> ntyp = 2, HL> ecutwfc = 40 , HL> ecutrho = 400 , HL> / HL> &ELECTRONS HL> mixing_mode = 'plain' , HL> mixing_beta = 0.7 , HL> diagonalization = 'david' , HL> / HL> ATOMIC_SPECIES HL> Zn 65.39200 Zn.pbe-van.UPF HL> O 16.00000 O.pbe-rrkjus.UPF HL> ATOMIC_POSITIONS crystal HL> Zn 0.666666667 0.333333333 0.000000000 HL> Zn 0.333333333 0.666666667 0.500000000 HL> O 0.666666667 0.333333333 0.380000000 HL> O 0.333333333 0.666666667 0.880000000 HL> K_POINTS automatic HL> 16 16 8 0 0 0 HL> HL> Can anyone help me to fix the problem? Thank you. HL> HL> Best wishes! HL> HL> Haiming Li HL> 2008-07-29 HL> HL> -------------- HL> Haiming Li HL> Beijing Synchrotron Radiation Facility HL> Institute of High Energy Physics HL> Chinese Academy of Sciences HL> 19 Yu Quan Lu, 100049 Beijing, P.R. China HL> Tel: 0086+10 8823 6437 / 0086+135 8190 2824 HL> E-mail:lihm at ihep.ac.cn HL> HL> _______________________________________________ HL> Pw_forum mailing list HL> Pw_forum at pwscf.org HL> http://www.democritos.it/mailman/listinfo/pw_forum HL> -- ======================================================================= Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu http://www.cmm.upenn.edu Center for Molecular Modeling -- University of Pennsylvania Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323 tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: 1-215-898-5425 ======================================================================= If you make something idiot-proof, the universe creates a better idiot.
