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How does Windows HPC choose which nodes to assign jobs to? RRS feed

  • Question

  • Hi,

    I have a small Windows HPC 2012 cluster with 20 32-core nodes and one 64-core node.  When I submit 150 single-tasking jobs to it, 38 are assigned to the 64-core node and 5 or 6 to each of the 20-core nodes.  I had assumed that the percentage load would be about the same across all nodes, but it turns out that the cluster manager is assigning jobs so that the number of unused cores is about the same on all nodes (64-38=26, 32-6=26).  I'm not sure I like that.  That means the the memory bus on the big machine is more heavily loaded.

    With 150 jobs, I'm using about 21% (150/704) of the cluster, so I would expect it to run 13 or 14 jobs on the big node and 6 or 7 on the smaller nodes.  That helps spread power consumption and heating more evenly.

    Is there a reason for the behavior and is there a setting that would assign jobs on a percentage basis, instead?

    Thanks in advance,

    Marshall

    Friday, February 7, 2014 5:36 PM

All replies

  • In this situation, I don't think HPC have global setting to assign jobs on a percentage basis. However, you may achieve it by setting min cores for each jobs. In this specific case, you have 704 cores and 150 jobs. If each job takes 4 cores (setting jobs' min cores to 4), the jobs should be distributed to machines much evenly.

    BR, Yizhong

    Monday, February 10, 2014 5:19 AM
  • If each job takes 4 cores (setting jobs' min cores to 4), the jobs should be distributed to machines much evenly.
    Each job takes one core, so that won't help.  Thanks, anyway, for responding.
    Monday, February 10, 2014 5:43 PM
  • If job's min core is set to 4, the job will reserve 4 cores although it only use 1 core. as a result, HPC will schedule 13-14 jobs to the 64 cores machine at the same time.

    BR, Yizhong

    Tuesday, February 11, 2014 3:02 AM
  • Well, it's not the answer I was hoping for, but I may try it when I have a certain number of jobs.  I'd have to change the min core depending on the number of jobs, which means I'd have to think about it.  ;-)  Thanks for the suggestion!

    Marshall

    Tuesday, February 11, 2014 4:12 PM