You are correct that the ZIIP dispatcher is not as sophisticated as the regular dispatcher. If a ZIIP request is made and no ZIIP engine is available the dispatcher will wait a period of time, see ZIIPAWMT parameter in IEAOPTxx, which if none is available by the end of that time, it will dispatch it on a GP engine rather than a ZIIP engine. This creates ZIIP_ON_CP time in your SMF data.
Because of this wait time, especially if it is large, you can elongate the elapsed time of whatever is running trying to use the ZIIP engines. By default that time is 3.2ms. The trick is to know when you are getting held up too much by ZIIP dispatch and skip trying to use it. I cannot remember right now the ROT for ZIIP percent active, but you cannot redline a ZIIP engine the way you can a GP engine. Chris Blaicher Technical Architect Mainframe Development Syncsort Incorporated 50 Tice Boulevard, Woodcliff Lake, NJ 07677 P: 201-930-8234 | M: 512-627-3803 E: [email protected] www.syncsort.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Jesse 1 Robinson Sent: Tuesday, July 19, 2016 11:47 AM To: [email protected] Subject: Re: DFsort and zIIP There is one potential zIIP performance problem that we learned about as we moved to DB2 V10, which enabled more zIIP processing than was available in V9. The scenario went something like this. zIIP dispatching was not as sophisticated as GP dispatching. If available zIIPs got overloaded, DB2 performance could be severely impacted by a thrashing condition. We actually added another zIIP engine in advance of the V10 cutover. I have no idea what might have happened otherwise. Was a bullet really dodged or merely imagined? I don't believe that this issue had anything specifically to do with SORT. . . . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 323-715-0595 Mobile 626-302-7535 Office [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Vernooij, CP (ITOPT1) - KLM Sent: Tuesday, July 19, 2016 7:42 AM To: [email protected] Subject: (External):Re: DFsort and zIIP The largest benefit is a financial one: you don't pay the zIIP MSUs. A performance benefit can come from the fact that the zIIP is always running at full speed, while your CP's can run at lower speeds. Kees. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Tom Marchant Sent: 19 July, 2016 16:39 To: [email protected] Subject: Re: DFsort and zIIP On Tue, 19 Jul 2016 08:26:45 +0200, Peter Hunkeler wrote: >>DFSORT can use zIIP on behalf of DB2 utilities, but not otherwise. >>Here's more information: > > >>At this time, IBM has no plan for enabling DFSORT to exploit the >>system z9 Integrated Information Processor (zIIP). IBM realizes >>DFSORT remains a prominent component of our customers' batch >>workloads. However, the added controls that would need to be >>implemented in order to maintain our high standards for performance, >>reliability and system integrity are not justified in view of >>estimations that there is a low offload potential and the value to >>clients may be marginal.....[snip] > >I seem to remember that SyncSort offers an Add-On package that allows >certain SyncSort processing to be offloaded to zIIPs. The above >statement suggest that SyncSort's perfocmance is suffering from using >zIIPs (simplified and exagerated, I know). I understood "there is a low offload potential and the value to clients may be marginal" as meaning that there would not be much benefit in using zIIP. Not that it would be worse. -- Tom Marchant ---------------------------------------------------------------------- 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
