Path: utzoo!mnetor!uunet!husc6!rutgers!iuvax!bsu-cs!dhesi From: dhesi@bsu-cs.UUCP (Rahul Dhesi) Newsgroups: comp.os.vms Subject: Re: Performance and batch jobs. Message-ID: <1732@bsu-cs.UUCP> Date: 19 Dec 87 23:33:11 GMT References: Reply-To: dhesi@bsu-cs.UUCP (Rahul Dhesi) Organization: CS Dept, Ball St U, Muncie, Indiana Lines: 21 Summary: operating system bug? In article WIZARD@RITA.ACS.WASHINGTON.EDU (The Bandit "." "." "." "", on" "RITA) writes: >We had a user here who submitted three batch jobs, and the system died. >Setting the base priority to 0 did not help. Suspending the processes did. >...The problem was that the virtual working set for these jobs >was huge, and the jobs were causing page faults like crazy. This sounds like a design flaw (i.e., a bug) in VMS's scheduling and/or memory management. A zero-priority job should simply remain swapped- out in its entirety most of the time. It should get swapped in only very rarely, and on those rare occasions, it should get all the pages it needs. It certainly ought not to bring the system down, unless the amount of disk space set aside for swapping is not enough--and if so, a well-designed system will simply abort the job with an out-of-memory or out-of-swap-space error message. Yes, there are systems that will die if three jobs do excessive paging (best exemplified by Primos revision 17), but I had expected VMS to be better able to protect itself from this. -- Rahul Dhesi UUCP: !{iuvax,pur-ee,uunet}!bsu-cs!dhesi