[cmucl-imp] x86-validate.h

[Raymond Toy]

On Tue, Aug 30, 2011 at 12:04 AM, Helmut Eller <heller at common-lisp.net>wrote:

> * Raymond Toy [2011-08-29 21:26] writes:
>
> >> (We should also have a mark&compact GC for the oldest generation, but
> >> that's another issue.)
> >>
> >>
> > Is there something wrong with the current Cheney copying collector that
> is
> > used for the oldest generation?  (I think that is what is used for the
> > oldest generation.)
>
> If we have a lot of stable memory, say 1GB in the oldest generation,
> then we need another 1GB for to-space to run the copying GC.  A
> compacting GC tries to move all live objects in the 1GB area to "one
> side", freeing up the holes left behind by dead objects.  That needs
> much less extra memory, I guess a few MB.  It may be a bit slower,
> though.
>
> An interesting idea.  Full GCs don't happen that often, I think, so the
slowdown, if any, may not be noticeable.  From some comments from Luke
Gorrie quite a long time ago, the main time spent in GC was actually in
GCing the static space.   At least for his test cases.

Ray