Very slow run of real.exe

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cyh082
Posts: 7
Joined: Fri Mar 29, 2019 5:49 am

Very slow run of real.exe

Post by cyh082 » Thu May 13, 2021 7:14 am

Hello,

I am trying to compile and run WRF model (version 4.2.2) on Linux cluster (CentOS 7).

I used intel 18 compiler with mvapich2.2 library and NetCDF 4.6.1 library (also tried version 4.1.3).

I selected configure option 15.

Actually, I did not have any error when I compiled WRF model.

However, when I tried to run WRF model with multiple nodes, WRF model (real.exe or wrf.exe) ran very slowly (slower than using single node).

Could you give me some advice on the above issue?

Thank you!

kwerner
Posts: 2287
Joined: Wed Feb 14, 2018 9:21 pm

Re: Very slow run of real.exe

Post by kwerner » Thu May 13, 2021 5:58 pm

Hi,
This topic has been moved from the compiling section to the real.exe section, as this is not a compiling issue. Someone will respond to your inquiry soon.
NCAR/MMM

Ming Chen
Posts: 1473
Joined: Mon Apr 23, 2018 9:42 pm

Re: Very slow run of real.exe

Post by Ming Chen » Thu May 13, 2021 7:10 pm

Would you please send us your namelist.input to take a look? Also, how many nodes (processors) did you use to run this case?
Please confirm that option 15 is intel compiler and the model was compiled in dmpar mode. Thanks.
WRF Help Desk

cyh082
Posts: 7
Joined: Fri Mar 29, 2019 5:49 am

Re: Very slow run of real.exe

Post by cyh082 » Fri May 14, 2021 2:58 am

Hello Ming Chen & kwerner,

I attached "namelist.input" file.

I used 2 nodes, and each node has 28 processors.

Thanks!

Yonghan
Attachments
namelist.input
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Ming Chen
Posts: 1473
Joined: Mon Apr 23, 2018 9:42 pm

Re: Very slow run of real.exe

Post by Ming Chen » Mon May 24, 2021 9:12 pm

Yonghan,
All the options in your namelist.input look correct and there is nothing wrong that would slow the model run. The intel compiler and dmpar mode are also fine. I talked to our software engineer and we are suspicious that the slow run of WRF is due to the mvapich library you used. Under certain circumstances, mvapich could run very slow. Would you please try other MPI libraries?
WRF Help Desk

cyh082
Posts: 7
Joined: Fri Mar 29, 2019 5:49 am

Re: Very slow run of real.exe

Post by cyh082 » Fri May 28, 2021 4:08 am

Hi Ming Chen,

Yes, as you suggested, I changed MPI library from mvapich to impi, and the problem was resolved.

Thank you for your kind help!

Yonghan

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