Date: Wed, 10 Dec 1997 02:59:11 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: chuckr@glue.umd.edu (Chuck Robey) Cc: tlambert@primenet.com, jonny@coppe.ufrj.br, freebsd-hackers@FreeBSD.ORG Subject: Re: Process scheduling: nice does not work ??? Message-ID: <199712100259.TAA02985@usr06.primenet.com> In-Reply-To: <Pine.BSF.3.96.971208215101.3522G-100000@picnic.mat.net> from "Chuck Robey" at Dec 8, 97 09:53:07 pm
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> > Standard UNIX priorities work like this:
[ ... ]
> I thought, Terry, that the effective priority slowly raised itself, with
> the length of time that it hadn't been run. The scheme you describe means
> that anything set to 19 never gets run at all, if there's a 20 (in fact I
> think the numbers are backwords, anyhow). Thats not the way I thought it
> was.
The numbers are backwards, yes.
> > Note: these are base priorities, which the system will adjust based on
**********************************************************************
> > I/O vs. CPU utilization.
***********************
Look at the PRI values in the original posting. The NI values are
irrelevant, no mattery his intent.
If he wanted to "lock" priorities, he need to use rtprio. Otherwise,
the scheduler will drift them as it sees fit.
IMO, Linux is implementing a "fairness" algorithm based on the NI value;
this is not traditional UNIX behaviour. It may favor interactive over
batch response. Note that he was running, effectively, batch processes;
this was my understanding the last time I looked at the Linux scheduler.
I think Linux is wrong, FWIW.
Terry Lambert
terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.
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