On 9/10/05, Xavier Leroy <Xavier.Leroy@inria.fr> wrote:

> I would have been very interested in a profiling of your initial
> implementation.  The only reason why the Caml hashtable can beat the
> global roots is that the latter are not generational: since the
> contents of registered global roots can change at any time without
> notifying the GC, all global roots must be scanned at every minor
> collection.

Yeah, we ran into this problem.  We had an application where we ended
up registering about 200,000 global roots (most of which were
callbacks.)  The application spent around 15% of the CPU all the time
just scanning global roots as part of minor collections.  The
callbacks were moved into a hashtbl,and these problems went away
completely.

Yaron