Date: Wed, 30 Mar 94 11:23:31 -0500
From: dj AT ctron DOT com (DJ Delorie)
To: eliz AT is DOT elta DOT co DOT il
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: DJGPP Speed

> Don't debugging and verifying mean constant recompilation?  DJ says that it
> takes him less than 30 minutes to compile GCC, which is less than pizza delivery
> time.  Of course, we in this remote region of ours have different schedules for
> pizza delivery, but slashing that down to, say, 10 minutes makes *a lot* of
> difference when developing a new version.

That time is for gcc -O2 from a *clean* directory - everything gets
compiled.  Most of the time, the CPU is in protected mode doing
optimization, and that's the bottleneck, even on a 486/66 with lots of
CPU cache.  I have enough memory in ramdisk and smartdrive to keep
that from being a problem, and my disk subsystem can sustain 4.5Mb/s,
so that's not the problem.

When doing debugging, chances are you're recompiling only a few
sources, and with -g instead of -O2.  Under these circumstances, the
compile takes much less time.

Note: gcc is 350K lines of code, not including system headers, in 137
C files and 92 headers.  327K lines of source are from the C files.