Date: Mon, 24 Nov 1997 08:52:28 +0100 (MET)
From: Thomas Knudsen <tk AT geb DOT gfy DOT ku DOT dk>
To: Ed Leiby <eiby AT frontiernet DOT net>
cc: djgpp AT delorie DOT com
Subject: Re: Intermittent Run-Time of DJGPP App under Win95
In-Reply-To: <3476E722.74E0@frontiernet.net>
Message-ID: <Pine.SGI.3.95.971124083316.29936A-100000@geb.gfy.ku.dk>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
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On 22 Nov 1997, Ed Leiby wrote:

...
> However, I have recently been hacking around w/ a DSP simulation
> compiled under gcc ( rev 2.7.2.1 ) using rhide ( rev 1.3 ) inside a
> win95 dos box on a Pentium Pro 200Mhz machine. I had previously been
> using Borland 5.01 set for a win95 console app, but had not been using
> any win32 specific anything. Well, the app compiled like a dream under
> gcc and ran right off, even reproducing results obtained under Borland.
> The problem is that it seems to run at two different speeds: As fast as
> Borland, and 2-3 times slower than Borland. I have tried using
> cwsdpmi,cwsdpr0 (rev 0.90+) and win95 DPMI server. However, to date I
> have not been able to correlate any action on my part or setup of the PC
> to the different execution speeds. I thought for a while that it had to
...
> 
> Ed Leiby


I have had the same experience with a GRX2.2+DJGPP based graphics program,
running in a DOS box under Win95. The symptoms are quite hard to describe
consistently (as they are quite inconsistent ;-), but at least *most* of
the time, the program tends to run slow, when running by itself, i.e. 
only sharing the processor power with the Win95 MegaKludge (TM). However,
if I open *another* DOS box, and have it sitting idle in the background,
suddenly the program runs at more than double speed. As it's a program
doing scientific animations (visual number crunching?) this really makes a
discernible difference---it would just be so nice to understand the cause
of the strange behaviour: Optimising the code for speed is pretty hard
when run times are inconsistent. So if any OS gurus could make sense from
this, please don't hesitate...

Perhaps, I should add, that *sometimes*, I have to open 2 more DOS boxes
to get the speed increase...

Thomas

--
Thomas Knudsen                         | www:  http://www.gfy.ku.dk/~tk/
National Survey and Cadastre - Denmark | e-mail:            tk AT gfy DOT ku DOT dk
Geodetic Dept., Rentemestervej 8       | Direct Phone:   +45 35 87 52 64
DK-2400 Copenhagen NV, Denmark         | FAX:            +45 35 87 50 52