<div>You need to check you bindings / number of processes. </div><div><br /></div><div>You request 52 processes. Does mpi use them? To make sure run with:</div><div> mpirun -n 52 ...</div><div><br /></div><div>If you don't have the CPU's and increase the number of OMP threads then they are run on the same processor, which will slow down the calculation as you have seen. </div><div><br /></div><div>You can also split between MPI and OPENMP:</div><div>mpirun -n 26 -c 2 --bind-to none .. </div><div><div>(The options might have different names depending on the MPI distribution). </div><br /></div><div><br /></div><div>Which splitting works the best depends on your system and on the type of computation. </div><div>In general more MPI processes require more memory as they have their copies, while openmp does not work over different nodes. </div><div>There is more MPI parallelization in CP2K, so this should work for most types of calculation. </div><div><br /></div><div><br /></div><br /><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Tuesday, April 28, 2026 at 4:30:01 PM UTC+2 Lorenzo Lagasco wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div>Ok, maybe I can test a bit more carefully the EPS_DEFAULT and EPS_ORB (I have already launched different tests for checking convergence on NGRIDS,CUTOFF and REL_CUTOFF). Meanwhile, this is my slurm submission script:<br>#!/bin/bash<br>#SBATCH --job-name=HSEO6<br>#SBATCH --nodes=1<br>#SBATCH --ntasks-per-node=52<br>#SBATCH --partition=taras2-6230r<br><br>module purge<br>module load cp2k/may2025-gnu14.2.0-openmpi4.1.6-psm211.2.230<br>export OMP_NUM_THREADS=1<br><br>mpirun cp2k.popt -i DYE+SLAB.inp -o DYE+SLAB.out<br><br><br></div>I tried to increase the number of OMP_NUM_THREADS from 1 to 2 or 3 and, as a result, the time required for each scf step is longer and longer. Moreover, I regulated the MAX_MEMORY in relation to the memory free of the node. </div><br><div class="gmail_quote"></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno mar 28 apr 2026 alle ore 16:00 Frederick Stein <<a href data-email-masked rel="nofollow">f.s...@hzdr.de</a>> ha scritto:<br></div></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Dear Lorenzo,</div><div>Are you sure that you need these tight cutoffs (EPS_DEFAULT and especially EPS_PGF_ORB)? Can you check how many integrals are recalculated (check the output file)? If they are, is it possible for you to increase MAX_MEMORY? How are you running CP2K (number of MPI ranks, number of OpenMP threads)?</div><div>Best,</div><div>Frederick</div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">Lorenzo Lagasco schrieb am Dienstag, 28. April 2026 um 15:43:45 UTC+2:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div></div></div></div><div><div><div><div dir="auto"><div><div><p>Good afternoon everyone,</p> <p>I am writing to ask for advice on how to improve the computational efficiency of an HSE06 calculation used to evaluate inter-state couplings between diabatic states in a slab–organic dye system (using the Kondov diabatization scheme, system containing 395 atoms). I have attached the input file for reference. In a preliminary test on a CPU-only machine (single node with 52 processors), a single SCF iteration takes approximately 30 minutes.</p> <p>Any suggestions would be greatly appreciated.<br><br></p><p>Best regards</p><p>Lorenzo Lagasco</p></div></div></div></div></div></div><br><br></div> </blockquote></div> <p></p></blockquote></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> -- <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br> To unsubscribe from this group and stop receiving emails from it, send an email to <a href data-email-masked rel="nofollow">cp2k+uns...@googlegroups.com</a>.<br> To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/439c2d51-5c6f-4fc9-be1b-1ff2884ab77an%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/msgid/cp2k/439c2d51-5c6f-4fc9-be1b-1ff2884ab77an%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1777475235908000&usg=AOvVaw0YkgwNMH_S77xaoaE_RQfU">https://groups.google.com/d/msgid/cp2k/439c2d51-5c6f-4fc9-be1b-1ff2884ab77an%40googlegroups.com</a>.<br> </blockquote></div> </blockquote></div> <p></p> -- <br /> You received this message because you are subscribed to the Google Groups "cp2k" group.<br /> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>.<br /> To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/173b3016-1da9-4054-bf0c-df730349b6fcn%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/173b3016-1da9-4054-bf0c-df730349b6fcn%40googlegroups.com</a>.<br />