Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!umich!samsung!brutus.cs.uiuc.edu!psuvax1!psuvm!MSU!RWWMAINT From: RWWMAINT@MSU.BITNET (Rich Wiggins) Newsgroups: bit.listserv.vmxa-l Subject: Re: Looking a way to limit interactive CPU utilization Message-ID: Date: 7 Feb 90 15:50:43 GMT Sender: VM/XA Discussion List Reply-To: VM/XA Discussion List Lines: 34 Approved: NETNEWS@PSUVM Gateway In-Reply-To: Message of Tue, 6 Feb 90 18:30:35 EST from > >I have been thinking about writing a REXX program that would run in a >disconnected service machine, and whose main task would be to have a look >at the system from time to time (every three minutes, for example); that >program would follow (using the CP INDICATE QUEUE command) those CPU bound >users, and would reduce their SHARE progressively; of course, certain users >(i.e., batch machines) would be excluded from the process. > >Because I do not want to reinvent the wheel, I first want to ask if anybody >has already written something similar. I would also be very glad to >accept comment and suggestions from other people. We have exactly the same sort of diverse mix, and exactly the same problem you detail: If our CPU crunchers would run via batch only, our load would be quite manageable, even though we run at 100% CPU utilization most of the time. Since they don't, I've implemented a simple little Rexx tool to do exactly what you propose. It's called QSCAN. It scans through IND POS lists to find people who seem to be getting lots of Q3 time, and slowly degrades their priority, eventually to be worse than that of the batch workers. This works fairly well. It cuts way down on the amount of CPU delivered to interactive crunchers. However, some folks don't get the hint, and on a busy day even the degraded crunchers have an impact. We did this under HPO 4.2. I'll be glad to send the exec along, especially if I get an XA-SP version back in return! /Rich Wiggins Computer Lab Michigan State U