Peter, I started off as saying, a lot of the descriptions are based on assumptions, as IBM has let out little on how the zIIP dispatcher works.
Also, I was only talking about SRBs on zIIPs, so non-enclave SRBs were not part of the discussion. I believe hyper dispatch is very different from zIIP dispatch. I stand by my assumption that GP dispatch is very different from zIIP dispatch, or why would there be the ZIIPAWMT parameter and have the comment about waking up after that interval to see if there is work. When non-zIIP work comes ready and a processor is free, the work is dispatched. No waiting. The comments in the parameter description for ZIIPAWMT is describing a polling environment, at least to me. I have looked through the internet, OK not the be-all and end-all but a reasonable place to start, and there is a lot on what can get dispatched on a zIIP, but no detail on how. As I said, I wish someone from IBM would at least chime in with some level of description as to how zIIP dispatch works and why high zIIP utilization rates are, shall we say, not good. Then maybe we can stop guessing. Chris Blaicher Technical Architect Mainframe Development P: 201-930-8234 | M: 512-627-3803 E: [email protected] Syncsort Incorporated 2 Blue Hill Plaza #1563 Pearl River, NY 10965 www.syncsort.com Data quality leader Trillium Software is now a part of Syncsort. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Peter Hunkeler Sent: Saturday, June 9, 2018 6:49 AM To: [email protected] Subject: AW: Re: Why are highly busy zIIPs worse than highly busy CPs? >First of all, the dispatcher code for ZIIP processing is not the same as the >GP dispatcher. Do you know this, or is it just an assumption on your side? After all I read, it still would't make sense to me. If you think of the "need help" process for the zIIP to be special, isn't there a similar process for CPs? With hiperdispatch, the system tries to redispatch work to the same (L)CP as much as possible. In support of this, the CPs are grouped into nodes (I believe that is the term). Each node mainly serving its own, separate work init queue. But CPs from other nodes will help if one node becomes overloaded. The above is how I remember it from a discussion I had with Robert Vaupel (IBM). -- Peter Hunkeler ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ________________________________ ATTENTION: ----- The information contained in this message (including any files transmitted with this message) may contain proprietary, trade secret or other confidential and/or legally privileged information. Any pricing information contained in this message or in any files transmitted with this message is always confidential and cannot be shared with any third parties without prior written approval from Syncsort. This message is intended to be read only by the individual or entity to whom it is addressed or by their designee. If the reader of this message is not the intended recipient, you are on notice that any use, disclosure, copying or distribution of this message, in any form, is strictly prohibited. If you have received this message in error, please immediately notify the sender and/or Syncsort and destroy all copies of this message in your possession, custody or control. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
