If you had a month to improve gcc build parallelization, where would you begin?

[Benjamin De Kosnik]

> > - Mechanical.  Configure scripts cause bottlenecks in the build
> > process.  Even if compilation is offloaded onto something like
> > distcc, configures run locally and randomly throughout the complete
> > build, rather than (say) all at once upfront.  Source code
> > compilation blocks until configure is completed.
> 
> - the configuration and build of the runtime libraries (libgcc,
>   libgomp, libstdc++) during the bootstrap is mostly serial.
> 
> - multilibs are built for stage2 and stage3, but are not needed.
>   multilib builds for the libararies are only needed for the final
>   build of the target libraries.

Yeah. I would concentrate on target library build improvements. 

IMHO, the number of top-level target libraries has proliferated in
recent years, but configuration bits are mostly copied and similar if
not identical. Fixing this for real would be a big win in terms of
speed, build comprehension, and future gcc features.

-benjamin