Xref: utzoo comp.windows.x:36959 comp.windows.x.motif:3121
Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!elroy.jpl.nasa.gov!thyme!kaleb
From: kaleb@thyme.jpl.nasa.gov (Kaleb Keithley)
Newsgroups: comp.windows.x,comp.windows.x.motif
Subject: Re: SCO Motif 1.0 problems (SCO has no plans to fix these)
Keywords: SCO ODT Motif 1.0, memory leaks, serious problems
Message-ID: <1991May29.180644.4661@thyme.jpl.nasa.gov>
Date: 29 May 91 18:06:44 GMT
References: <1991May24.172352.23135@grebyn.com> <645@fudd.dataco.UUCP>
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 49

In article <645@fudd.dataco.UUCP> campbell@fritz.UUCP (Duncan Campbell, VOR) writes:
>Recipe 7.  Do not use Motif for real time applications.  In fact
>I have serious misgivings about the use of GUIs in a real time 
>application: they suck cpu cycles and memory like there's nothing
>else to do and provide very little more than a nice warm fuzzy
>feeling.

Really?  What facts do you base these assertions on?  In as much as you
can do anything in "real time" on vanilla UNIX, we're doing real time
monitoring of the Deep Space Network using Sun 4-330s, MIT X11R4, and 
Motif 1.1.  CPU loads for a typically "loaded" workstation run around
the following:

                      average/peak %
    Xsun:                3     17 
    display clients:     0     10

    user                 10    50

These numbers were garnered from the top program during different stages
of stress and load testing.  There's nothing scientific about how I
came up with them; they're seat of the pants numbers.  But if 0% of the
CPU is "suck(ing) cpu cycles like there's nothing else to do", then I'd
like to know what a non-cpu intensive program is?  The display clients
do peak at 10%, but that's generally when a new display is being created,
and there's lots going on.  

It's easy for any application to be cpu hungry, they don't even have to 
be GUI based.  Our display clients initially used (worse case) 15% cpu 
at a nominally idle state.  A profile run showed that we were beating up 
the system with excessive system calls.  After reengineering our semaphore 
strategy, cpu usage dropped to an indicated 0%.

X11R4/Motif, in our real time application works A-okay.  It's fast,
it's good looking, and it doesn't core dump.  Which would you rather show 
a Congressman or a visiting foreign dignitary, a bank of 20 year old 
character based terminals, or state-of-the-art workstations running a GUI?

I too have serious misgivings, but it's not about using a GUI on for
a mission critical application.  It's about the willingness to use vanilla 
UNIX for a *real* real-time application, considering that there's nothing
remotely *real-time* about UNIX.  Is it a coincidence that of all the GUIs, 
only one runs on a *real* real-time operating system?

-- 

Kaleb Keithley                               kaleb@thyme.jpl.nasa.gov

No flashy sig. No clever quips. No famous quotes. This space for rent.