gcc 3.3 garbage collector defaults

[Geoff Keating]

Mike Stump <mstump@apple.com> writes:

> On Monday, January 27, 2003, at 11:04 AM, David Edelsohn wrote:
> >>>>>> Benjamin Kosnik writes:
> >
> > Ben> Aaaaaaaaaaghh!!!!!! Why aren't these flags documented!!!! Why
> > aren't
> > Ben> the defaults sane???
> >
> > 	The defaults are very sane for a 128MB 200MHz system :-).
> 
> Can you please support that with timing runs?  Compare with a 16MB and
> a 32MB run, and show us the numbers, thanks.  Personally, I think we
> should bump the numbers to 32MB.  Apple has been shipping with 8MB as
> the default for a while now, even that number I think is too small.
> If no one can come up with data to support low numbers and we can come
> up with data to support 16MB, I think it would be bad to keep the
> number too small.

I have evidence that on one machine, a two-processor machine with
128Mb of memory, that GCC starts to thrash when it uses more than
about 40Mb of memory and two copies are running (this makes sense,
2*40Mb of GCC plus about 50Mb for the system = thrashing). This sort
of thing is why I want to try an adaptive approach.

-- 
- Geoffrey Keating <geoffk@geoffk.org>