Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!tut.cis.ohio-state.edu!ucbvax!agate!shelby!neon!torrie
From: torrie@cs.stanford.edu (Evan J Torrie)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Single user OS schedulers (Was Re: How do we change the scheduler?)
Message-ID: <1991Jan27.223145.18292@Neon.Stanford.EDU>
Date: 27 Jan 91 22:31:45 GMT
References: <1991Jan23.213736.28220@Neon.Stanford.EDU>   <1991Jan24.152931.1325@NCoast.ORG><1991Jan25.073516.29644@Neon.Stanford.EDU>   <1991Jan26.035750.11786@NCoast.ORG><1991Jan27.014242.2863@Neon.Stanford.EDU> <189704d7.ARN27ab@prolix.ccadfa.oz.au>
Sender: torrie@Neon.Stanford.EDU (Evan James Torrie)
Organization: Computer Science Department, Stanford University
Lines: 42

dac@prolix.ccadfa.oz.au (Andrew Clayton) writes:

>In article <1991Jan27.014242.2863@Neon.Stanford.EDU>, Evan J Torrie writes:

>Huh?  The OS doesn't interfere with your DECISION to run multiple programs at
>the same time.  By default, spawned programs have a priority of zero (0) thus
>they *share equitably* the CPU resource.

  It's my contention that the OS should poke its nose into this,
though, by PREFERRING interactive tasks over compute intensive.  Even
Unix does this, by aging tasks based on its recent CPU usage, and I
would argue that on a single user OS, this preference for interactive
tasks should be even more pronounced.

>Duh!  Lets make the OS democratic!  :-).  *YOU*, all by your lonesome, get to
>make the decision if you want processes to have priority.  Most people don't
>mess with the scheduler.  It's best left alone.

  The problem is, though, that the decision to give a process a
particular priority is a static decision.  What do you do about
processes, which spend most of their time being interactive (so you
give them a bump up in priority), but then, every now and again go
into a compute intensive loop.
  Sure you can let the user do everything.  If the system starts
getting slow, the user has to find out which task is causing the
slowdown, and then statically change it to a lower priority.
  Wouldn't a more dynamic scheduler built into the OS be a better solution?

>In other words, if it ain't broke, don't fuck with it.

  I'm not saying it's broken.  I'm asking whether it could be
improved..., and whether anyone has ever done any comparative studies
on the various merits of single user schedulers.

(P.S.  this thread is rapidly getting stale, so it will probably cease
to exist in the near future)

-- 
------------------------------------------------------------------------------
Evan Torrie.  Stanford University, Class of 199?       torrie@cs.stanford.edu   
"If it weren't for your gumboots, where would you be?   You'd be in the
hospital, or in-firm-ary..."  F. Dagg