z/OS Container Extensions (zCX)

z/OS Container Extensions (zCX)

z/OS Container Extensions (zCX)

Deploying Linux on Z containerized applications inside z/OS

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Is it normal to have 100% zIIP usage even without any running containers?

  • 1.  Is it normal to have 100% zIIP usage even without any running containers?

    Posted Wed May 17, 2023 07:49 PM

    Hi,
    I've just started using zCX, basically only with the SSH CLI container active, and in SDSF I see the zCX address space running nearly always with 100% zIIP usage.  I don't have SMT enabled yet.  If I enable SMT will this change, or is it normal to have such high zIIP usage regardless of how many containers may be in use?

    This is z/OS 2.5 at PUT2303/RSU2303. 

    Docker --version reports:
    Docker version 20.10.12, build 20.10.12-0ubuntu2~20.04.1

    Thanks,

    Peter



    ------------------------------
    Thanks and regards,
    Peter Bishop
    ------------------------------


  • 2.  RE: Is it normal to have 100% zIIP usage even without any running containers?

    Posted Fri May 19, 2023 01:42 AM

    Well, a bit more digging shows that this seems to be an SDSF feature, showing which jobs are using zIIPs as a percent of all jobs using zIIPs, as RMF only shows the zCX address space rarely using the zIIPs.

    During normal idling, RMF shows the zCX job using about 5% of a zIIP.  Starting a container takes it up to about 30% for a minute or two.

    So, false alarm...

    Thanks for your patience  :-)



    ------------------------------
    Thanks and regards,
    Peter Bishop
    ------------------------------