Newsgroups: comp.unix.internals
Path: utzoo!utgpu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!alchemy.chem.utoronto.ca!system
From: system@alchemy.chem.utoronto.ca (System Admin (Mike Peterson))
Subject: Re: "Nice" or not to "nice" large jobs
Message-ID: <1991May22.134525.21624@alchemy.chem.utoronto.ca>
Keywords: scheduling priority nice
Organization: University of Toronto Chemistry Department
References: <1991May16.140622.29266@alchemy.chem.utoronto.ca> <4281@inews.intel.com> <4293@inews.intel.com>
Date: Wed, 22 May 1991 13:45:25 GMT

>In article <4281@inews.intel.com> bhoughto@hopi.intel.com (Blair P. Houghton) writes:
>>In article <1991May16.140622.29266@alchemy.chem.utoronto.ca> system@alchemy.chem.utoronto.ca (System Admin (Mike Peterson)) writes:
>>>Our policy for nice/renice is:
>>>0  - "short" processes/jobs (compilations, or up to 5 minutes cpu time).
>>>1  - "medium" processes/jobs (up to 1 hour cpu time).
>>>2  - "long" processes/jobs (all other jobs).
>>
>>That's all but affectless.

The main problem with your discussion of BSD scheduling is that Apollo
Domain/OS does not use BSD scheduling - as I said in my posting, renice
values of 2 to 20 inclusive result in the same Domain/OS priority range,
so they are all exactly equivalent. Renice '1' is sufficiently
different that such a process will get almost zero cpu time if a renice
'0' process is running, and a renice '2'-'20' process will get almost no
time if a '0' or '1' process is running (always assuming cpu-bound).

I would love to have more choice of renice values that are really
different (I don't really care what they are, but 4, 8, 12, 16, 20 are
fine with me, or 5, 10, 15, 20); I don't really care if higher renice
value jobs don't get any cpu time if other jobs are running (though O/S
designer types might worry about it, and therefore let long jobs at
least do something every once in a while).

Mike.
-- 
Mike Peterson, System Administrator, U/Toronto Department of Chemistry
E-mail: system@alchemy.chem.utoronto.ca
Tel: (416) 978-7094                  Fax: (416) 978-8775