Hello, How can I minimize inter-node MPI communication in a pw.x run? My system doesn't have Infiniband and inter-node MPI can easily become the bottleneck. Let's say, I'm running a calculation with 4 k-points, on 4 nodes, with 56 MPI tasks per node. I would then use -npool 4 to create 4 pools for the k-point parallelization. However, it seems that the diagonalization is by default parallelized imperfectly (or isn't it?): Subspace diagonalization in iterative solution of the eigenvalue problem: one sub-group per band group will be used scalapack distributed-memory algorithm (size of sub-group: 7* 7 procs) So far, speedup on 4 nodes vs 1 node is 3.26x. Is it normal or does it look like it can be improved?
Best regards, Michal Krompiec Merck KGaA Southampton, UK _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users