Date: Tue, 21 Jan 1997 09:44:27 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Andreas Mustun <ribbon AT active DOT ch>
cc: djgpp AT delorie DOT com
Subject: Re: DJGPP 1 -> DJGPP 2 -> slower program speed?
In-Reply-To: <32E3510B.29AF@active.ch>
Message-ID: <Pine.SUN.3.91.970121093937.26269T-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On Mon, 20 Jan 1997, Andreas Mustun wrote:

> But my disappointment was big. My program is about 20 times
> slower using DJGPP 2 than DJGPP 1! I used the same compiler-
> options (-O2 -m486) I also tryed by using -O6. But the speed
> was the same: *much* slower. BTW I use GRX2.0 also.
> 
> Who can help me make my prog faster (as fast as in DJGPP 1)?

The FAQ, for starters.  Please download the latest version 2.10 of the FAQ
(v2/faq210b.zip) and read section 14.2 there.  It has been expanded and
enhanced in the last FAQ release and will give you some ideas to try. 

In general, DJGPP v2 produces code which is always faster than that of 
v1.x.  Your problem most probably is due to use of some library functions 
or techniques that are inherently inefficient.  You should profile your 
program to see where the hot spots are and try to speed them up.  If you 
can't figure out why a certain function or code fragment takes so long, 
post the code here and somebody will help.