Re: GCC 4.1: Buildable on GHz machines only?

["Joel Sherrill <joel at OARcorp dot com>" <joel dot sherrill at OARcorp dot com>]

Peter Barada wrote:
> > Well, yes.  1 second/file is still slow!  I want "make" to complete
> > instantaneously!  Don't you?
>
>
> Actually I want it to complete before I even start, but I don't want
> to get too greedy. :)
>
> What's really sad is that for cross-compilation of the toolchain, we
> have to repeat a few steps (build gcc twice, build glibc twice)
> because glibc and gcc assume that a near-complete environment is
> available(such as gcc needing headers, and glibc needing -lgcc-eh), so
> even really fast machines(2.4Ghz P4) take an hour to do a cross-build
> from scratch. 

That sounds comparable to the time required to build RTEMS toolsets.  I 
just looked at the timestamp on the build logs for a gcc 4.0.0 CVS build 
with newlib 1.13.0 and it is on the order of 60-90 minutes per target on 
a 2.4 Ghz P4 w/512 MB RAM.  This is just C and C++ and the variance is 
probably mostly due to the number of multilibs.

I checked build logs of gcc 3.3.5 with newlib 1.13 from December on the 
same machine and times were comparable so it isn't a recent slowdown.

When I built my native 4.0.0 on this machine, I did notice that 
compiling the Java libraries took long enough to notice and when I did a 
top, I noticed that gjc was running for 30+ seconds of CPU time with RSS 
on the order of 150 MB.  Another time I noticed that sh had taken 90 
seconds and that was an invocation of libtool with a very long command line.

Here is the configure command and output of time on this machine for a 
gcc 4.0.0 build:

../gcc-4.0.0/configure --prefix=/opt/gcc-4.0.0 
--enable-languages=c,c++,ada,java,objc

4271.94user 685.49system 1:31:18elapsed 90%CPU (0avgtext+0avgdata 
0maxresident)k0inputs+0outputs (33176183major+40970199minor)pagefaults 
0swaps

A 2.4 Ghz P4 isn't what I would consider an obsolete machine and it took 
90 minutes for "make" -- not a full bootstrap.

--joel