Jim, Thank you for the clarification, however, that still leaves open the question of WHY more than 30% on a single zIIP or 60% on two is not a good idea.
That is what triggered this whole chain of emails. Why can GPs run reasonably well at over 95% and zIIPs struggle, or so people have reported. We are a development shop and so rarely, if ever, push them that hard. We have, but that was doing things you would not do in the real world, like having a loop in your code you didn't know about. :) If you can't tell us the why, can you tell us what reasonable utilization numbers are for a range of numbers of zIIPs? I think the user community as a whole is interested. Chris Blaicher Technical Architect Mainframe Development P: 201-930-8234 | M: 512-627-3803 E: cblaic...@syncsort.com 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:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Jim Mulder Sent: Saturday, June 9, 2018 12:53 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Why are highly busy zIIPs worse than highly busy CPs? zIIP dispatching is the same as GP dispatching. ZIIPAWMT has analogous parameters for GP (CCCAWMT) and zAAP (ZAAPAWMT). Alternate wait management was created long before there were specialty engines. Jim Mulder z/OS Diagnosis, Design, Development, Test IBM Corp. Poughkeepsie NY "IBM Mainframe Discussion List" <IBM-MAIN@LISTSERV.UA.EDU> wrote on 06/09/2018 10:58:25 AM: > From: "Christopher Y. Blaicher" <cblaic...@syncsort.com> > To: IBM-MAIN@LISTSERV.UA.EDU > Date: 06/09/2018 12:46 PM > Subject: Re: Why are highly busy zIIPs worse than highly busy CPs? > Sent by: "IBM Mainframe Discussion List" <IBM-MAIN@LISTSERV.UA.EDU> > > 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. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu 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 lists...@listserv.ua.edu with the message: INFO IBM-MAIN
