[gclist] GC for multi-threaded and multi-processor systems?

[David Bruce]

Hi!

Some colleagues and I have been developing a parallel simulation system,
though to date we have been able to do the bulk of our work in a purely
sequential setting, for which the Boehm-Demers-Weiser collector has been
entirely adequate.

However, we now do need to move to multi-threaded and multi-processor
(shared-memory, for now) versions, and would appreciate advice from
anyone who has trod a similar route.

The documentation for the BDW collector (v4.11) explains how to
configure it for Solaris threads (we're using Suns, so that's OK), which
would make it MT-safe, but I'm concerned that this might not be
sufficient for a truly parallel system: alloc.c/solaris_threads.c
suggest that it stops the world (all the LWPs in the process) to do its
collection, thereby forming a potentially serious parallel bottleneck,
but how severe is this in practice?  (Or have I misunderstood how it
works?)  Does the BDW collector have a truly parallel version (and if
not, does its incremental mode help?), or can anyone recommend another
garbage collector that does?  Finally, are there any nasty gotchas I
should know about with any of the above?

Sincerely,

    Dastatically vid Bruce
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