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From: "Randy Brukardt" <randy@rrsoftware.com>
To: <comp.lang.ada@ada-france.org>
Subject: RE: How come Ada isn't more popular?
Date: Fri, 9 Feb 2007 12:47:32 -0600
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Date: 2007-02-09T19:50:03+01:00

> Maciej Sobczak <no.spam@no.spam.com> writes:
> > Still, there is a strong argument is that for some class of algorithms
it
> > might be beneficial to be able to "drop on the floor" a bigger part of
the
> > graph altogether. [...] Reclaiming that abandoned part might require
> > implementing the same tracking logic that GC already provides out of the
box
> > and therefore the argument goes that the use of off-the-shelf GC can be
> > beneficial for the memory-management aspect of such an algorithm. (Any
> > thoughts on this?)
>
> My thoughts: not "might", but "definitely". Also, the advantage is not
> restricted to some class of algorithms -- it is in fact the common case.

YMMV, of course, but it's not my experience. It's rare to destroy only part
of a data structure; it's usually the entire structure that needs to be
discarded.

> You don't need a complex mesh for this kind of advantage to kick in, even
> regular tree cleanup is greatly simplified: just let go of the
> subbranch you no longer need, and avoid that whole cleanup traversal.

I'm primarily interested in destroying the entire structure, and often I
need no destruction at all: the structures exist until the termination of
the program. There's no point of earlier cleanup in such programs, and
surely no point in non-zero overhead to support such cleanup. I'm not aware
of any zero-overhead GC algorithm, because the basic tenet of GC is that you
can find all reachable objects: doing that requires some time and/or space
overhead.

                       Randy.