On 11/23/2012 10:45 AM, Jonathan Wakely wrote:
Actually, this observation may favor a real garbage collector. Marking GC as
simple as ggc+gengtype usually have one (or a few) mark bits, so can consume
only a few bits (or perhaps a byte in some mark array) per object. Copying
GC could avoid consuming any more storage per object. Of course useless
object may stay in memory for a while -until the GC deletes them or reuse
their memory-
The research shows significantly higher memory usage when relying on
GC in large systems.
I believe the research treats reference counting as a form of GC. 8-)
It would be an interesting project to instrument GCC to obtain the
precise point when any object becomes unreachable, synthesize a sequence
of malloc()/free() calls from that, and run it against a traditional
malloc implementation. I believe this is how some of the early research
into GC memory overhead was done (at much, much smaller heap sizes for
sure).
--
Florian Weimer / Red Hat Product Security Team
