Newsgroups: comp.sys.amiga.tech
Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!sharkey!msuinfo!convex.cl.msu.edu!jap
From: jap@convex.cl.msu.edu (Joe Porkka)
Subject: Re: Does AmigaDOS drive with one foot on the brake?
Message-ID: <1990Aug14.053356.15973@msuinfo.cl.msu.edu>
Sender: news@msuinfo.cl.msu.edu
Organization: Michigan State University
References: <1673@blackbird.afit.af.mil>
Distribution: usa
Date: Tue, 14 Aug 90 05:33:56 GMT

ecottle@falcon.afit.af.mil (Eugene T. Cottle) writes:


>    It started with a question about input.device.  Now I am wondering
>whether AmigaDOS is intentionally trying to slow down my program.

>single task use more than 50% of the CPU time.  I have seen two CPU
>intensive tasks together use more than that, but never one.

>nothing going on except Xoper (no mouse movement, no joystick, etc.) it
>hovers around 10% CPU time.  When I run the number cruncher (no other
>changes), input.device uses over 20% CPU time.  The program does no I/O
>during that time.

AmigaDos is not related to UNIX.

The task scheduler is simple round robin - The task of highest
priority readqy to run gets to run. If there are more than one task
at that priority level, then they get an equal chance at the CPU.

The 10% figure also includes overhead eaten up by DMA for video, sounds
disk, etc...

To check to see if you program is leaving any CPU unused, try this:
ChangeTaskPri -5
run SimpleBusyDemo - Like the lines demo from Workbench 1.2
ChangeTaskPri 0
run your program.

If the lines program runs AT ALL after you start your program, then
there idle times in your program, most likly caused by IO, or
even graphics could cause some (CPU waiting for the blitter).

