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From: ohk@ultra.tfdt-o.nta.no (Ole-Hjalmar Kristensen FOU.TD/DELAB)
Subject: Re: Ada versus Java - Tasking
Date: 1997/01/18
Message-ID: <OHK.97Jan18194202@ultra.tfdt-o.nta.no>#1/1
X-Deja-AN: 210690849
references: <01bc03ee$594dc520$829d6482@joy.ericsson.se>
organization: Telenor Online Public Access
newsgroups: comp.lang.ada
Date: 1997-01-18T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <32DFC320.41C67EA6@innocon.com> Jeff Carter <carter@innocon.com> writes:

< Stuff deleted>

   Here are some typical outputs:

   C:\ada>prod_cons
    18.340000000

   C:\ada>prod_cons
    18.180000000

   C:\ada>prod_cons
    19.170000000

   C:\ada>prod_cons
    18.120000000

   C:\ada>prod_cons
    19.660000000

   C:\ada>prod_cons
    17.850000000

   C:\ada>prod_cons
    17.630000000

   C:\ada>prod_cons
    18.010000000

   These give an average of 18.37 seconds per run. While not as good as 15
   seconds, this is better than 30 seconds.

   These figures are for GNAT 3.04a on a P120, 32MB, Win95. Built using

      gnatmake -O3 -gnatn prod_cons.adb

   I conclude the 62-pair limitation is not related to amount of memory.

   I would be interested in knowing how Jonas' version differs from mine.
   -- 
   Jeff Carter
   Innovative Concepts, Inc.


These task switching times are still pretty horrible though. Using
Unix processes and pipes or System V message queues, you can do just
as well. Any idea of why this is so? Does it follow from the
definition of an Ada task, or is it just this particular
implementation.
 
With a task switching overhead of this magnitude, tasks become
unattractive as a way of programs dealing with high-speed IO, for
example.