Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!PAN.SSEC.HONEYWELL.COM!thompson
From: thompson@PAN.SSEC.HONEYWELL.COM (John Thompson)
Newsgroups: comp.sys.apollo
Subject: Process Priorities
Message-ID: <9010220501.AA09206@pan.ssec.honeywell.com>
Date: 22 Oct 90 05:01:44 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 32

I like Apollos, I really do....  In fact, I want to buy one for myself, BUT...

This problem is specifically occurring on our 2-cpu DN10000, but the problem
exists on all other machines as well.  We have 4 or 5 groups that have work
to do on our DN10000.  All of them would like to have top priority, but as
things go, only 2 groups have been given the "top priority" stamp from upper
management.  These groups are allowed to raise their jobs' low-priority #
up to 5.

The problem is that most of the jobs are cpu-intensive.  Very rapidly, 
everyone drops down to their lowest priority. As soon as we get >= NUM_CPUs
high priority jobs running, everyone else can kiss their cpu-time goodbye.  
There is no mechanism for processes that are swapped out to have their
priorities rise over time, until they are allowed to swap back in.
Since the high-priority jobs don't have disk, execute, memory, I/O, etc
faults to wait on, they run merrily along.

What we would like is a mechanism that gives out cpu time to all intensive 
jobs, not just the high-priority ones.  If process priorities aged while
they were INVOLUNTARILY swapped out, we could probably find a set of
priorities that gave the approximate percentages.

Am I mistaken, or do _real_ unix priorities age the way I want DomainOS
priorites to?

John Thompson (jt)
Honeywell, SSEC
Plymouth, MN  55441
thompson@pan.ssec.honeywell.com

As ever, my opinions do not necessarily agree with Honeywell's or reality's.
(Honeywell's do not necessarily agree with mine or reality's, either)