There WAS a corner case and at least one customer I knew of had it: With ICFs you could expand into shared engines - with the "non expansion" case being all dedicated. That went away some time ago. I think what you said about z10 corroborates my memory that Dynamic ICF Expansion was only supported on z9 and prior. (Fair mucked up my CPU reporting and as it was going anyway I deigned not to fix my code.) :-)
Cheers, Martin Martin Packer, Mainframe Performance Consultant, zChampion Worldwide Banking Center of Excellence, IBM +44-7802-245-584 email: [email protected] Twitter / Facebook IDs: MartinPacker Blog: https://www.ibm.com/developerworks/mydeveloperworks/blogs/MartinPacker From: Skip Robinson <[email protected]> To: [email protected], Date: 16/02/2012 05:07 Subject: Re: Dedicated vs. Shared CPs Sent by: IBM Mainframe Discussion List <[email protected]> I checked out an MVS Image profile on my (brand spanking new!) z196. It looks the choice is between dedicated or shared CPs. A CF LPAR offers more choices, but oddly fewer choices than the z10 it replaced. . . JO.Skip Robinson SCE Infrastructure Technology Services Electric Dragon Team Paddler SHARE MVS Program Co-Manager 626-302-7535 Office 323-715-0595 Mobile [email protected] From: Barbara Nitz <[email protected]> To: [email protected] Date: 02/15/2012 08:58 PM Subject: Re: Dedicated vs. Shared CPs Sent by: IBM Mainframe Discussion List <[email protected]> >Is it possible to mix shared and dedicated CPs on the same LPAR? No. Not on a z9 and not the way you mean. The RMF report deals with what an lpar can look like when it uses Hiperdispatch. That is not available on a z9. Hiperdispatch semi-dedicates logical processors to physical processors depending on the workload. And most probably depending on the number of physical cps. (Which is why we asked for the number of your physical cps in the other thread - you haven't answered that!) Once hiperdispatch is on, a physical cp gets a weight, which can be low, medium or high. High amounts to being (semi-)dedicated. >Does anyone run mixed like this, a dedicated number to cover the minimum expected MSU of an LPAR, then some logicals to float between LPARS? Everyone who uses hiperdipatch. >Does anyone know what is needed in terms of outages/lpar resets to move from a completely logical CP environment to a mixed environment? An upgrade to a machine supporting hiperdispatch. Which means at least one IPL. But as you can see from my questions starting this thread, it is possible that you cannot use hiperdispatch - whenever your logical to physical cp ratio is so bad that 4 or more logical cps compete for one physical, due to the number of lpars you have, for instance. In the very first presentation I heard (by Bob Rogers) about hiperdispatch, he said that it will turn itself off if the ratio is really bad. I haven't heard that confirmed anywhere, though. And coming from a z9 presumably to a z196, chances are very good that you would loose physical cps to keep money down. Try making your bosses understand that they cannot use the same number of logicals when the number of physicals decreases.... Barbara Nitz ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
