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w784370882 December 30, 2018 06:48
CFX parallel computing questions
 
Hello， everyone, thanks for your attention! I use HPC for CFX calculation. I'm a new learner using 'ssh -X node01' to open CFX and my questions are as follows:
1. I can only use one node for calculation, how am I supposed to use multiple nodes?
2. In each node, there are 2 CPUs and each has 10 cores, but the total processors are 40. So what is the maximum number of processes I may use？ 20 or 40?
3. when I use uptime to check current cpu load it's very high. Is there a maximum uptime value limit? I'm afraid that if the load is too high the server maybe overheated and get damaged.

That's 3 questions I want to ask you guys. :)Thanks again!

ghorrocks December 31, 2018 06:04
1) Look in the CFX documentation and setup manuals for distributed parallel setup.
2) It appears you have 20 physical cores and 20 virtual cores. The virtual cores are from hyperthreading. Hyperthreading does not work with CFX so do not use the virtual cores. You can use them if you like, there is nothing stopping you, but the simulation speed will be poor. CFX only runs fast on physical cores.
3) You can set CFX to run for specified times if you like. But I have never heard of a HPC cluster which cannot run at full speed continuously. HPC clusters are intended to run at full speed continuously. So you will be fine unless you have bought cheap computers or overclocked them. Also make sure there is adequate air flow around them so they can cool properly.

w784370882 January 1, 2019 00:39
Code:
SIMULATION CONTROL:
  EXECUTION CONTROL:
    PARALLEL HOST LIBRARY:
      HOST DEFINITION: mgmt
        Installation Root = /home/App/ansys_inc/v%v/CFX
        Host Architecture String = linux-amd64
      END # HOST DEFINITION mgmt
      HOST DEFINITION: node01
        Installation Root = /home/App/ansys_inc/v%v/CFX
        Host Architecture String = linux-amd64
      END # HOST DEFINITION node01
      HOST DEFINITION: node02
        Installation Root = /home/App/ansys_inc/v%v/CFX
        Host Architecture String = linux-amd64
      END # HOST DEFINITION node02   
      HOST DEFINITION: node03
        Installation Root = /home/App/ansys_inc/v%v/CFX
        Host Architecture String = linux-amd64
      END # HOST DEFINITION node03
      HOST DEFINITION: node04
        Installation Root = /home/App/ansys_inc/v%v/CFX
        Host Architecture String = linux-amd64
      END # HOST DEFINITION node04
      HOST DEFINITION: node05
        Installation Root = /home/App/ansys_inc/v%v/CFX
        Host Architecture String = linux-amd64
      END # HOST DEFINITION node05
  END # PARALLEL HOST LIBRARY
  END # EXECUTION CONTROL
END # SIMULATION CONTRO

w784370882 January 1, 2019 00:40
The problem has been solved and I learn a little more about HPC, thank you sir and happy new year!


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