Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!husc6!think!ames!sdcsvax!nosc!humu!uhmanoa!uhccux!helen From: helen@uhccux.UUCP (Helen Rapozo) Newsgroups: comp.os.vms Subject: Re: Running images at priority 1 Message-ID: <684@uhccux.UUCP> Date: Wed, 15-Jul-87 01:43:08 EDT Article-I.D.: uhccux.684 Posted: Wed Jul 15 01:43:08 1987 Date-Received: Fri, 17-Jul-87 03:21:34 EDT References: <8707110202.AA28088@ucbvax.Berkeley.EDU> Organization: U. of Hawaii, Manoa (Honolulu) Lines: 34 Summary: Doing useful work In article <8707110202.AA28088@ucbvax.Berkeley.EDU>, 13501ADC@MSU.BITNET ("Alan D. Cabrera") writes: > > I've been submitting CPU intensive batch jobs on our VAX 8650 with the > priority set at 1. It uses some pretty big arrays so it tends to page > ALOT. When I run my job people say that they notice a degredation to > the system. I say that my job shouldn't pose a problem because it's > priority is lower than theirs. > > Am I wrong in assumming that since my job's priority is set at 1, it > shouldn't interfere with anybody with a higher priority? The only reason why a job running at priority 1 is executing is because the other process on the system that have priority 2 to 31 is not using the CPU in the first place. If you think about the NULL process runs at priority 0 so if the system is not doing anything else it will execute that process which happens to be an infinite loop. If this job that runs at priority 1 is doing useful work then the system is doing more useful work. Seriously tho, since the job pages a lot that could explain the degredation in response time. You could do the following things: a) Run the job at priority 0. What will happen is that whatever CPU cycles that are left will be split between NULL and your process. b) Somehow get a bigger working size for your job, the less paging you do the faster things will go. c) If you are the system manager there is a parameter that deals with the timeslice, if you decrease the timeslice the effect to the users will be one of faster response time. Let me know how this turns out.