[PyKDE] Possible problem with PyQt and PyKDE

[Jim Bublitz]

On Saturday 15 October 2005 08:17, Detlev Offenbach wrote:
> Hi,
>
> I have just installed SUSE 10 on my computer. It uses gcc 4.0.2 as it's
> compiler. Thereafter I tried to compile PyQt having used the -c option for
> configure.py. It took a very long time (ca. 20 min. on a 3 GHz machine),
> without finishing the compile. After that first try, I compiled it without
> the -c option and, voila, it compiled ok. Same happened to PyKDE. Here I
> had to use the -i option to disable concatenation.
>
> Is this a known issue or what am I doing wrong?

Same here - I just installed SuSE 10 also. What appears to have changed is the 
memory usage of gcc. gcc appears to be much faster. PyKDE with the -i switch 
will now compile in 70 minutes on an 800Mhz machine, which used to take about 
3 hours. That particular machine also has 512MB of RAM and won't compile PyQt 
with the -c switch or PyKDE *without* the -i switch.

My recommendations would be:

1. PyQt - don't use -c
2. PyKDE - do 'python configure.py -i'
3. For gcc 4.0.2 you have to use either the KDE bindings version of PyKDE or 
used the latest snapshot (20051013) at:    
    
      http://www.riverbankcomputing.co.uk/snapshots/PyKDE


-c for PyQt and the normal PyKDE build systems concatenate all of the cpp 
files into 1 or 2 huge files, which with older gcc versions compiles as much 
as 80% faster than compiling a single cpp file at a time. Not using -c PyQt, 
or using -i for PyKDE makes sip create a single cpp file per class (more or 
less) - for PyKDE that's over 600 cpp files. New gcc versions apparently use 
a lot more memory to get the speedups they have, and choke on the huge 
concatenated files, but are much faster in the file-per-class situation.

Compiling might complete with the -c switch on PyQt, but the heavy use of swap 
slows it down to a crawl.

Compile times will be slightly longer than the previous concatenated compile 
times, but not as bad as compile times used to be without concatenating.

Jim