Hello Bang,

For comparison, in my case I have been able to run a vc-relax job on 92 atoms, 
48 cores in 12 hours. I am using USPP, gamma point calculation and no symmetry. 
This is a slab. I am using a basic command line: mpirun -np 40 pw.x < input > 
output.  

Of course, I do not know if our computers are comparable, but it seems that 
your performance could be improved, probably through compilation optimization. 
I am using national supercomputer facility and QE was installed by a system 
manager, so I cannot give compilation details.

I have noted a few things in your input that I (personally) would change:
Energy convergence=1d-7
Force convergence=1d-4 eventually 1d-5 if you plan to compute phonons (in any 
case it should not be smaller than energy convergence)
conv_thr=1d-8 (or smaller — 1d-9, 1d-10 -- in case of phonon calculations only)
It seems that your are using USPP, so in this case I think you can reduce 
Ecutwfc to between 30-50, but you have to test this, and Ecutrho should be 
between 8 and 12 times Ecutwfc.
Check also if you can reduce the number of k-points: your cell seems to be 
rather large.

HTH
Pascal


Le 1 sept. 2015 à 21:18, Bang C. Huynh <[email protected]> a écrit :

> Dear all,
> 
> I am currently attempting to perform several structural relaxation 
> calculations on supercells that contain at least ~70 atoms (and even more, 
> say hundreds). My calculations are being done on a single node with 40 cores, 
> 2.4 GHz, Intel Xeon E5-2676v3 and 160 GiB memory (m4.10xlarge Amazon EC2). I 
> am just wondering if my implementation for parallelism is 'reasonable' in the 
> sense that the resources are fully utilised, and not in some way 
> underutilised or poorly distributed. I'm pretty new to this so I'm not sure 
> what to expect... Should I be happy with the current performance, can it be 
> better, or should I consider deploying more resources and is it worth it? 
> Currently one scf iteration takes around 5-7 minutes. Scf-convergence is 
> achieved after around 50 scf iterations, and I'm not sure how long it's going 
> to take for the vc-relax iterations to converge...
> 
> The input file is shown below. I use this command to initiate the job:
> 
>> mpirun -np 40 pw.x -npool 2 -ndiag 36 < skutU0.125_vc.vc2 > 
>> skutU0.125_vc.vc2.out
>> 
> Thank you for your help.
> 
>  
> Regards,
> 
> -- 
> Bang C. Huynh
> Peterhouse
> University of Cambridge
> CB2 1RD
> The United Kingdom
> 
> ========input=======
> 
>> &CONTROL
>> title = skutterudite-U-doped ,
>> calculation = 'vc-relax' ,
>> outdir = './' ,
>> wfcdir = './' ,
>> pseudo_dir = '../pseudo/' ,
>> prefix = 'skutU0.125_vc' ,
>> etot_conv_thr = 1.0D-5 ,
>> forc_conv_thr = 1.95D-6 ,
>> nstep = 250 ,
>> dt = 150 ,
>> /
>> &SYSTEM
>> ibrav = 6,
>> celldm(1) = 17.06
>> celldm(3) = 2,
>> nat = 66,
>> ntyp = 3,
>> ecutwfc = 93 ,
>> ecutrho = 707 ,
>> occupations = 'smearing' ,
>> starting_spin_angle = .false. ,
>> degauss = 0.02 ,
>> smearing = 'methfessel-paxton' ,
>> /
>> &ELECTRONS
>> conv_thr = 1D-10 ,
>> /
>> &IONS
>> /
>> &CELL
>> cell_dynamics = 'damp-w' ,
>> cell_dofree = 'all' ,
>> /
>> ATOMIC_SPECIES
>> Co 58.93000 Co.pz-nd-rrkjus.UPF 
>> Sb 121.76000 Sb.pz-bhs.UPF 
>> U 238.02891 U.pz-spfn-rrkjus_psl.1.0.0.UPF 
>> ATOMIC_POSITIONS crystal 
>> Co 0.250000000 0.250000000 0.125000000 0 0 0 
>> Co 0.250000000 0.250000000 0.625000000 0 0 0 
>> Co 0.750000000 0.750000000 0.375000000 0 0 0 
>> Co 0.750000000 0.750000000 0.875000000 0 0 0 
>> Co 0.750000000 0.750000000 0.125000000 0 0 0 
>> Co 0.750000000 0.750000000 0.625000000 0 0 0 
>> Co 0.250000000 0.250000000 0.375000000 0 0 0 
>> Co 0.250000000 0.250000000 0.875000000 0 0 0 
>> Co 0.750000000 0.250000000 0.375000000 0 0 0 
>> Co 0.750000000 0.250000000 0.875000000 0 0 0 
>> Co 0.250000000 0.750000000 0.125000000 0 0 0 
>> Co 0.250000000 0.750000000 0.625000000 0 0 0 
>> Co 0.250000000 0.750000000 0.375000000 0 0 0 
>> Co 0.250000000 0.750000000 0.875000000 0 0 0 
>> Co 0.750000000 0.250000000 0.125000000 0 0 0 
>> Co 0.750000000 0.250000000 0.625000000 0 0 0 
>> Sb 0.000000000 0.337592989 0.078553498 
>> Sb 0.000000000 0.337592989 0.578553498 
>> Sb 0.000000000 0.662407041 0.421446502 
>> Sb 0.000000000 0.662407041 0.921446502 
>> Sb 0.000000000 0.662407041 0.078553498 
>> Sb 0.000000000 0.662407041 0.578553498 
>> Sb 0.000000000 0.337592989 0.421446502 
>> Sb 0.000000000 0.337592989 0.921446502 
>> Sb 0.157106996 0.000000000 0.168796495 
>> Sb 0.157106996 0.000000000 0.668796480 
>> Sb 0.842893004 0.000000000 0.331203520 
>> Sb 0.842893004 0.000000000 0.831203520 
>> Sb 0.157106996 0.000000000 0.331203520 
>> Sb 0.157106996 0.000000000 0.831203520 
>> Sb 0.842893004 0.000000000 0.168796495 
>> Sb 0.842893004 0.000000000 0.668796480 
>> Sb 0.337592989 0.157106996 0.000000000 
>> Sb 0.337592989 0.157106996 0.500000000 
>> Sb 0.662407041 0.842893004 0.000000000 
>> Sb 0.662407041 0.842893004 0.500000000 
>> Sb 0.662407041 0.157106996 0.000000000 
>> Sb 0.662407041 0.157106996 0.500000000 
>> Sb 0.337592989 0.842893004 0.000000000 
>> Sb 0.337592989 0.842893004 0.500000000 
>> Sb 0.500000000 0.837592959 0.328553498 
>> Sb 0.500000000 0.837592959 0.828553498 
>> Sb 0.500000000 0.162407011 0.171446502 
>> Sb 0.500000000 0.162407011 0.671446502 
>> Sb 0.500000000 0.162407011 0.328553498 
>> Sb 0.500000000 0.162407011 0.828553498 
>> Sb 0.500000000 0.837592959 0.171446502 
>> Sb 0.500000000 0.837592959 0.671446502 
>> Sb 0.657106996 0.500000000 0.418796480 
>> Sb 0.657106996 0.500000000 0.918796480 
>> Sb 0.342893004 0.500000000 0.081203505 
>> Sb 0.342893004 0.500000000 0.581203520 
>> Sb 0.657106996 0.500000000 0.081203505 
>> Sb 0.657106996 0.500000000 0.581203520 
>> Sb 0.342893004 0.500000000 0.418796480 
>> Sb 0.342893004 0.500000000 0.918796480 
>> Sb 0.837592959 0.657106996 0.250000000 
>> Sb 0.837592959 0.657106996 0.750000000 
>> Sb 0.162407011 0.342893004 0.250000000 
>> Sb 0.162407011 0.342893004 0.750000000 
>> Sb 0.162407011 0.657106996 0.250000000 
>> Sb 0.162407011 0.657106996 0.750000000 
>> Sb 0.837592959 0.342893004 0.250000000 
>> Sb 0.837592959 0.342893004 0.750000000 
>> U 0.000000000 0.000000000 0.000000000 
>> U 0.000000000 0.000000000 0.500000000 
>> K_POINTS automatic 
>> 4 4 2 0 0 0
>> 
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--
Pascal Boulet - MCF HDR, Resp. L1 MPCI - DEPARTEMENT CHIMIE
Aix-Marseille Université - ST JEROME - Avenue Escadrille Normandie Niemen - 
13013 Marseille
Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50
Site : http://allos.up.univ-mrs.fr/pascal - Email : [email protected]
Afin de respecter l'environnement, merci de n'imprimer cet email que si 
nécessaire.

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