IDMS

  • 1.  Multitask CV

    Posted Jan 05, 2017 10:27 AM

    One of our production cv's has been set to multitask since the beginning of time.

     

    Over the years we have upgraded processors, now on a z13, and increased our MIPS allowance.

     

    I'm just wondering if we need to run with multitasking on anymore.  Is there a rule of thumb?

     

    Any thoughts or recommendations are appreciated.

     

    Here are the numbers for a cv that's been up 18 days.

     

             

        • Display all subtasks ***

                    Work            Task dispatch

    Name       Nr  type  Status         count        Wakeup count   Total CPU time

    -


           --  -


      -


        -


         -


       -


    MAINTASK   01  IDMS   IDLE         8,494,031          343,180    10:04.247647

    SUBT0001   02  IDMS   BUSY        50,615,148        3,698,225    56:59.790171

    SUBT0002   03  IDMS   BUSY       274,807,079       37,264,304   05:50:33.4251

    SUBT0003   04  IDMS   BUSY      2,571,797e03     1,979,407e03   2:13:38:24.50

    V1  ENTER NEXT TASK CODE:      CA IDMS release 19.0 tape GJJ04I node IDMSV01

     

     

     

        • Subtask display ***

    Subtask          Elapsed time                  Total CPU time         % CPU  SRB

    Name         TCB            SRB            TCB            SRB       TCB SRB

    -


    -


    -


    -


    -


    --- ---

    MAINTASK   15:17.715290   00:00.000000   10:04.433510   00:00.000000  65 N/A  N

    SUBT0001  01:35:29.0673   00:00.000000   57:00.071678   00:00.000000  59 N/A  N

    SUBT0002  08:12:10.6985   00:00.000000  05:50:34.5794   00:00.000000  71 N/A  N

    SUBT0003  3:06:42:24.82   00:00.000000  2:13:38:31.38   00:00.000000  78 N/A  N

    -


    -


    -


    -


    -


    --- ---

    Totals    3:16:45:22.30   00:00.000000  2:20:36:10.46   00:00.000000  77 N/A

    V1  ENTER NEXT TASK CODE:      CA IDMS release 19.0 tape GJJ04I node IDMSV01

     

     

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  • 2.  Re: Multitask CV

    Posted Jan 05, 2017 10:57 AM
      |   view attached

    I guess that depends on your task make-up

     

    I9 have no empirical data to support my opinion – just my thoughts

     

    If your threads do NO waiting – then MT might hu8rt you -  cpu overhead with little benefit

     

    If your threads do a lot of waiting  - (i.e. time when the idms environment is waiting for something to do) – then MT might improve throughput time)

     

    So I guess the cpu  may not be the determining factor in deciding to MT; it is the time when the cpu is NOT used that may determine if/when to MT

     

     

     

     

    Chris Hoelscher

    Technology Architect, Database Infrastructure Services

    Technology Solution Services

    : humana.com

    123 East Main Street

    Louisville, KY 40202

    Humana.com

    (502) 714-8615, (502) 476-2538



  • 3.  Re: Multitask CV

    Posted Jan 05, 2017 12:41 PM

    DCMT D MPMODE output might also be useful to look at.