<div>Dear Mauro,</div><div><br></div><div>This is consistent with my own observations of the scaling of xTB. Because of the increasing cost of communication more CPUs don't necesarily speed up the simulation. I don't use more than 25 CPUs with xTB unless I have well above 1000 atoms.</div><div><br></div><div>Please note that the number of MPI ranks should be a square number. 25 CPUs are probably faster than 28 unless you are using k-points.<br></div><div><br></div><div>Cheers,</div><div>Fabian<br></div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Monday, 22 February 2021 at 11:10:11 UTC+1 chu...@gmail.com 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>Hi Mauro,</div><div><br></div><div>it will be easy to look into your scaling issue if you report time for each MD step. I am also doing MD with xTB.<br></div><div><br></div><div>Regards</div><div><div><div dir="ltr" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div>Manjusha<br></div></div></div></div></div></div><br></div></div><br><div class="gmail_quote"></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Feb 22, 2021 at 10:59 AM Mauro Sgroi <<a href data-email-masked rel="nofollow">mauro...@gmail.com</a>> wrote:<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">Dear all,<div>I'm testing the xTB code on a liquid electrolyte containing a Li ion.</div><div>I'm running MD on a cell containing 728 atoms.</div><div>I obtain a disappointing scaling with the number of cores. The following are times for 100 MD steps:</div><div><br></div><div><div>cores Time (s)</div><div>28 7818 </div><div>56 7364</div><div>84 6529</div><div>112 7493</div></div><div><br></div><div>My input file can be downloaded here: </div><div><br></div><div><a href="https://drive.google.com/file/d/1KvZz5x6FwgOP3dzH6fePghMQBineIlfE/view?usp=sharing" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://drive.google.com/file/d/1KvZz5x6FwgOP3dzH6fePghMQBineIlfE/view?usp%3Dsharing&source=gmail&ust=1614075335392000&usg=AFQjCNEel7XgWsyBiSo7teB5svb0H0cC8Q">https://drive.google.com/file/d/1KvZz5x6FwgOP3dzH6fePghMQBineIlfE/view?usp=sharing</a></div><div><br></div><div>Is this the right behaviour to be expected? Or is there is something wrong in my compilation of the code or in the input file? </div><div>The HPC facility has a Infinband network protocol and a fast shared filesystem.</div><div><br></div><div>Thanks a lot in advance and best regards,</div><div>Mauro Sgroi.</div><div><br></div><div><br></div><div><br></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">cp...@googlegroups.com</a>.<br> To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/162a9eac-2a85-4d76-a4c2-08305f29cf5bn%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://groups.google.com/d/msgid/cp2k/162a9eac-2a85-4d76-a4c2-08305f29cf5bn%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1614075335392000&usg=AFQjCNENxTlT7PQwND7jiToegExCEgYsMQ">https://groups.google.com/d/msgid/cp2k/162a9eac-2a85-4d76-a4c2-08305f29cf5bn%40googlegroups.com</a>.<br> </blockquote></div> </blockquote></div>