Performance issues with Cons

[Warren_Baird]

Hi all,

I don't know if anyone else is seeing this, but we're finding that cons is
pretty slow...  We've got a moderately sized project (currently generating about
2500 object files, from a mixture of C and C++ source files), and it's taking
something like 15-20 seconds for cons to actually start compiling any files, on
a pretty zippy dual UltraSparc-III - 900Mhz, I think...

Now, our include heirachy is pretty bad - a lot of source files include a lot
more header files than they really need to...  So I assume that most of that
time is spent building up and checking the dependancies...  I'm hoping to fix
the include heirarchy, but it's not going to be a quick thing, and I'm not
positive how much that's going to speed up cons...

Has anyone done any work on improving this?  I haven't spent much time looking
at the code inside cons, so I don't know if the code itself could be made more
effiicient, but it seems like it should be possible to cache the include
dependancies somewhere, and only rebuild them when a source file changes...

The delay is getting annoying for developers, and I'm having trouble defending
the decision to use cons instead of gnu-make with some kind of 'make depend'...

Any suggestions on how I could speed things up?   Does anyone know if scons
handles this kind of situation any better?

Thanks!

Warren