>the 'speed' (GHz) is always the same for all types The 'speed' is not generally thought to be the cycle time. It is true that the cycle time is the same across the models, but the effective speed is not the same (such as MIPS or the MSU rating).
>the dispatcher code for ZIIP processing is not the same as the GP dispatcher. Well, it is "the same" but there are swizzles (such as the fact that a zIIP processor will not run CP work, but a CP might run zIIP work). >the queuing process is basically FIFO The queueing process is the same. For all processors it can be thought of as FIFO for a specific priority (where the priority has many sub-factors) >It runs to the end or a program break point happens. A program break point could be some form of PAUSE or a IEAVXTSW wait. zIIP work is timed just like CP work. There are dispatch durations established and when the duration is exceeded, the timeslice ends and the work will be undispatched if there is equal or higher priority work to run. That applies regardless of the type of processor. It might be, but is not necessarily, the case that the dispatch durations are the same for the different processor types. You really want Gary King or Dan Rosa to chime in, not me. I can rarely keep the details straight. If they provide me with information to relay on their behalf, I will be glad to. Much of the discussion has been on target. If zIIPs are "overloaded" then the work queues for zIIP will get "too long" and the zIIPs will ask for "help". The percentages mentioned to some extent translate into how likely it is that something will not find the resources available and then must "wait" (or get someone else to do it). "Help" is a very complex process which can include helping from other zIIPs (in part related to hiperdispatch trying to run work as close as possible to the original work to limit negative cache effects) and possibly CPs. If you're running CPs at 100% and zIIPs need "help", then something is going to suffer. You just don't have enough resources for the work you're trying to accomplish. Then there are also the questions of whether or not you allow CPs to help or insist that zIIP-eligible work run only on zIIPs. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
