gcc+gcj build-times?

Andrew Haley aph@redhat.com
Wed Feb 22 13:35:00 GMT 2006


Norman Hendrich writes:
 > Hello all,
 > 
 > after some absence I tried my luck with gcj again (2006.02.18 snapshot).
 > However, it seems that I did something wrong:
 > 
 > 1) building gcc 4.2.0 20060218 (C,C++,Java) took over _three hours/
 >    on my Athlon 2600+ machine. For comparison, I last built gcc/gcj
 >    before the classpath merge, which completed in about 35 minutes (iirc) 
 >    on the same machine. This is on gnu-linux-x86 with gcc-4.0.0 as my 
 >    system compiler.

We now do a full bootstrap by default; you can configure with
--disable-bootstrap if you wish.

 >    Is this normal?   
 > 2) I "only" have 512 MBytes RAM on this machine. Building gcj (both
 >    "make" and crazily also "make install") required a smidgen more than 
 >    512 megs with corresponding swapping and an unusable machine during
 >    several minutes.

This is probably the real cause of the slowdown.

 >    Is this intentional?  Do you get provision from DRAM vendors? :-)
 > 
 >    
 > 3) The resulting compiler seems to work, but AWT/Swing performance is
 >    not what I expected. Actually, jamvm+classpath runs some of my test
 >    apps faster than gcj -O3 ...  see next post for an example.
 > 
 > 
 > Any insights as how to speed up build-times or why AWT/Swing might 
 > end up crawling under gcj are really appreciated.

The solution for speeding up build times is pretty obvious: you just
don't have enough RAM.  It might be that we could reorganize things a
bit, but at some point we have to link the library, and that takes
memory.

Andrew.



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