Timo is of course right. Nevertheless, your parallel output shows that the program isn't executed in a distributed way. It simply executes the full sequential code on four processes that don't communicate with each other. The four processes occupy two physical cores resulting in a degradation in performance. The sequential (in the sense of temporal discretization and coupling) 2p2c model is not parallel. The fully implicit ones are parallel, also the sequential 2p model is parallel. Let us know if you experience the same problems with a truly parallel model. If you do so, please consider Timo's comment that you choose a number of processes that is less or equal than the number of physical cores on your machine.
Kind regards Bernd -- _______________________________________________________________ Bernd Flemisch phone: +49 711 685 69162 IWS, Universität Stuttgart fax: +49 711 685 60430 Pfaffenwaldring 61 email: be...@iws.uni-stuttgart.de D-70569 Stuttgart url: www.hydrosys.uni-stuttgart.de _______________________________________________________________ ________________________________ Von: Dumux <dumux-boun...@listserv.uni-stuttgart.de> im Auftrag von Timo Koch <timo.k...@iws.uni-stuttgart.de> Gesendet: Donnerstag, 24. Januar 2019 11:01:56 An: DuMuX User Forum; lc Betreff: Re: [DuMuX] set_singular_limit and parallel execution Hi Lorenzo, you can't scale well to 4 cores because your CPU only has two cores. The two additional ones are only hyperthreads. Please repeat the same numerical experiment on a machine with more cores. Timo On 24.01.19 10:37, lc wrote: On 18.01.2019 21:52, Flemisch, Bernd wrote: Can you please post the complete output for the run with 4 cores? Plus the initial vtk files? And, pretty please with sugar on top, the number of physical cores on your machine? Good morning, I enclose the requested files for the sequential (1 processor) and parallel (4 processors) simulations plus some detail on my machine. Thanks for help, Lorenzo _______________________________________________ Dumux mailing list Dumux@listserv.uni-stuttgart.de<mailto:Dumux@listserv.uni-stuttgart.de> https://listserv.uni-stuttgart.de/mailman/listinfo/dumux -- _______________________________________________________________ Timo Koch phone: +49 711 685 64676 IWS, Universität Stuttgart fax: +49 711 685 60430 Pfaffenwaldring 61 email: timo.k...@iws.uni-stuttgart.de<mailto:timo.k...@iws.uni-stuttgart.de> D-70569 Stuttgart url: www.hydrosys.uni-stuttgart.de<http://www.hydrosys.uni-stuttgart.de> _______________________________________________________________
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