Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uwm.edu!ogicse!adaptive!asi.com!casey
From: casey@asi.com (Casey Bahr)
Newsgroups: comp.realtime
Subject: VxWorks task scheduling
Keywords: round-robin, task priorities, scheduling
Message-ID: <907@adaptive.UUCP>
Date: 29 Mar 91 01:24:18 GMT
Sender: casey@adaptive.UUCP
Reply-To: casey@asi.com (Casey Bahr)
Distribution: usa
Organization: Adaptive Solutions Inc., Portland OR
Lines: 30

Are there any VxWorks scheduling gurus out there? Hello?

I have an application that normally runs about 5 concurrent tasks
and over the course of develpoment I've had some trouble in getting 
them scheduled equally by the OS (running on an mvme147).  Before 5.0
my solution was to hand-tune the priorities to get everyone going, which
seemed to work fine, once I found the proper relative priorities.

Now with 5.0 most of the tasks seem to get scheduled fine, except
one, which seems to get locked out (waiting at a socket accept() call).
So, I tried using the round-robin scheduling feature by calling
kernelTimeSlice() with values from 1 to 10 (seemed reasonable) and
combining that with leaving my task priorities as they were without
round-robin, and by changing the priorities to be equal (as implied
by the VxWorks release notes).  Using round-robin scheduling seemed
to make matters worse, by seemingly shutting out > 1 task.

Worse yet, after using round-robin scheduling interrupts from
the console terminal keyboard seemed to be all messed up, not
taking strokes, doubling or tripling them up, etc.  Had to shut
down the mvme147 to correct this.  Not sure this latter symptom
is relevant, but it was entertaining.

Any experiences relevant to my situation and possible solutions
much appreciated.  Thanks in advance :}

Casey Bahr  
casey@asi.com | ogicse!adaptive!casey | uunet!adaptive!casey 
Adaptive Solutions, Inc., 1400 NW Compton Dr. Suite 340, Beaverton, OR 97006  
VOICE: (503) 690.1236 /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ FAX: (503) 690.1249