[CP2K-user] [CP2K:14808] Scaling with xTB

[fa...@gmail.com]

Dear Mauro,

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.

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.

Cheers,
Fabian

On Monday, 22 February 2021 at 11:10:11 UTC+1 chu... at gmail.com wrote:

> Hi Mauro,
>
> 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.
>
> Regards
> Manjusha
>
>
> On Mon, Feb 22, 2021 at 10:59 AM Mauro Sgroi <mauro... at gmail.com> 
> wrote:
>
>> Dear all,
>> I'm testing the xTB code on a liquid electrolyte containing a Li ion.
>> I'm running MD on a cell containing 728 atoms.
>> I obtain a disappointing scaling with the number of cores. The following 
>> are times for 100 MD steps:
>>
>> cores  Time (s)
>> 28         7818 
>> 56         7364
>> 84         6529
>> 112       7493
>>
>> My input file can be downloaded here: 
>>
>>
>> https://drive.google.com/file/d/1KvZz5x6FwgOP3dzH6fePghMQBineIlfE/view?usp=sharing
>>
>> 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? 
>> The HPC facility has a Infinband network protocol and a fast shared 
>> filesystem.
>>
>> Thanks a lot in advance and best regards,
>> Mauro Sgroi.
>>
>>
>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "cp2k" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to cp... at googlegroups.com.
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/cp2k/162a9eac-2a85-4d76-a4c2-08305f29cf5bn%40googlegroups.com 
>> <https://groups.google.com/d/msgid/cp2k/162a9eac-2a85-4d76-a4c2-08305f29cf5bn%40googlegroups.com?utm_medium=email&utm_source=footer>
>> .
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20210222/2ce49bd3/attachment.htm>