gcc 3.3 garbage collector defaults

[Benjamin Kosnik]

>One has to be careful. e.g. many people run make with -j2 on principle on
>single CPU systems to hide IO latencies [anybody interested in POSIX aio prefetch
>for gcc btw ?;]  Also when I have a multi CPU box I need enough memory
>for -j$[2*nrcpus]  (or [4*nrcpus] with hyperthreading) and still not swap
>out my window manager and editor. All these cases should not suddenly start to swap.
>
>Rough proposal: 
>
>Main memory < 512MB: 16MB 
>            < 1GB:   64MB
>			> 1GB:   128MB

Well, not quite sure memory over 16MB helps, actually:

time make CXXFLAGS="--param ggc-min-heapsize=16384 --param ggc-min-expand=50"
193.816u 30.121s 3:49.56 97.5%  0+0k 0+0io 524642pf+0w

time make CXXFLAGS="--param ggc-min-heapsize=32000 --param ggc-min-expand=70"
186.494u 30.662s 3:42.65 97.5%  0+0k 0+0io 524417pf+0w

>Also it would be nice to make it settable via an environment variable. 

Is that necessary if there is already a flag?

-benjamin