I wasn’t involved in this design but this makes perfect sense: You’ve told WLM you don’t care how slowly that work runs – so why cross over?
Cheers, Martin From: IBM Mainframe Discussion List <[email protected]> on behalf of Sebastian Welton <[email protected]> Date: Tuesday, 4 February 2025 at 07:31 To: [email protected] <[email protected]> Subject: [EXTERNAL] Re: Use of ZIIPS This actually came up in a Watson & Walker Tuning Newsletter some time ago and basically there is a special aspect of the workload manager (WLM) service class goal of “discretionary.” If a zIIP exists and the workload is zIIP-eligible and in a discretionary service period, the workload is dispatched only on zIIP processors even if CPs are idle. For example, if you are running z/OSMF with your zPDT system that has 3 CPs, you see a specific period for z/OSMF start. Then, if you add a zIIP, the z/OSMF start takes much longer because much of z/OSMF is dispatched only to the single zIIP processor. This situation occurs for any application that has large amounts of zIIP-eligible code. Sebastian. On Mon, 3 Feb 2025 16:21:06 +1100, Attila Fogarasi <[email protected]> wrote: >The obvious explanation is that your zowe workload doesn't have more active >threads than zIIPs most of the time. Note that not all of zowe is zIIP >eligible, most of the CLI and APIML are zIIP eligible. Much of the CLI is >single threaded per client and sounds like you have few clients for zowe. >As an aside, on zPDT its probably faster to run with no zIIP as the >emulation gives no advantage to zIIP and just pollutes the x86 cache. > >On Wed, Jan 29, 2025 at 12:31 AM Colin Paice < >[email protected]> wrote: > >> I am running Zowe on my zPDT system. >> >> The ZIIPS are running flat out ( with waits for ZIIPS) but the GCPs are >> pretty idle. >> >> Ive IIPHONORPRIORITY=YES which says use GCP if shortage of ZIIP. >> >> Is there anything else I should be looking at? >> >> Colin >> >> ---------------------------------------------------------------------- >> For IBM-MAIN subscribe / signoff / archive access instructions, >> send email to [email protected] with the message: INFO IBM-MAIN >> > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN Unless otherwise stated above: IBM United Kingdom Limited Registered in England and Wales with number 741598 Registered office: Building C, IBM Hursley Office, Hursley Park Road, Winchester, Hampshire SO21 2JN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
