From shenkin[ AT ]still3.chem.columbia.edu  Thu Feb  3 18:46:51 1994
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Date: Thu, 3 Feb 94 17:59:28 -0500
From: shenkin:~at~:still3.chem.columbia.edu (Peter Shenkin)
Message-Id: <9402032259.AA22244:~at~:still3.chem.columbia.edu>
To: <WILLIAMS%XRAY2 /at\ULKYVX.LOUISVILLE.EDU>, chemistry /at\ccl.net
Subject: Re:  CCL:Deprioritizing SGI unix runs


> From: <WILLIAMS%XRAY2 |-at-| ULKYVX.LOUISVILLE.EDU>
> Date: Thu, 03 Feb 1994 14:21:38 -0500 (EST)
> Precedence: bulk
> 
> 	I recall that there was a message over the net about something
> better than "nice" (which hardly works at all).  Can anyone tell me
> how to keep background jobs from slowing foreground jobs to a
> crawl?  Thanks.

"man npri";  example:  (as superuser, unless it's your job):

	npri -h 150 -p <process-id>

will give the existing job <process-id> a non-degrading priority of 150.  
High priorities (like high "nice" values) slow the process down.  150 is
a good value for background jobs which should never preempt interactive 
work to a significant extent.  In other words, a job with this priority,
if it's the only user process on the system, will use 99+% of the CPU
(e.g., at night), but it will use essentially 0% if someone is at the
console interacting with, say, a molecular graphics program.

The difference between npri and nice is that npri gives a *non-
degrading* priority.  "nice" affects the aging of priorities.

You can also say, "npri -h 150 <jobname> <job_args>" to start up a job 
with a non-degrading priority of 150.

Hope this helps....

	-P.

*****************************************************************************
********************** "So much for global warming...." *********************
Peter S. Shenkin, Box 768 Havemeyer Hall, Dept. of Chemistry, Columbia Univ.,
New York, NY  10027;     shenkin&$at$&still3.chem.columbia.edu;     (212) 854-5143