Faster compilation speed

[Robert Dewar]

<<Well, at some point space "optimizations" do actually become functional
requirements. When you need to have a gigabyte of real memory in order to
compile some things in a reasonable timeframe, it has definitely become
functional ;)
>>

Interesting example, because this is just on the edge. We are just on the point
where cheap machines have less than a gigabyte, but not by much (my notebook
has a gigabyte of real memory). In two years time, a gigabyte of real memory
will sound small.

It is always hard to know how to target main memory requirements (Realia
COBOL, one of the fastest compilers ever written for the PC, it compiled
100,000 lines/minute on a 386, was targetted to work in 64K bytes, we did
not make that, it required 130K bytes :-)

But of course it is not clear that caches get larger that quickly, so the
point Linus is making about cache usage is certainly valid, though it would
be nice to have measurements rather than just rhetoric [on both sides of
the issue].