[gclist] Precise GC's performance

[Urs Hoelzle]

Antony Hosking writes:
> Following up on this topic of accurate versus conservative collection, I'll
> put in a blatant plug for some work a student of mine and I are currently
> doing.  We have resurrected (and extended) the original work of Diwan et al
> [PLDI'92] on accurate GC for the now-defunct UMass GNU Modula-3 effort.  We've
> taken that original design and much of the gcc-backend code, modified the SRC
> M3 front-end to emit the necessary type information, and extended the gcc
> backend to handle certain complications of modern RISC architectures, so that
> we can now accurately collect several significant Modula-3 programs (e.g.,
> m3browser).  We're still in debugging mode so I won't say we handle all the
> programs we've tried (moreover, unsafe programs can break the accurate
> collector by hiding pointers, etc., though I'm sure they could be rewritten to
> cooperate without too much trouble).  In any case, we should very shortly be
> in a position where we can run direct comparison of accurate copying versus
> Bartlett-style mostly-copying conservative roots collection, for gcc-optimized
> Modula-3 programs, with hard results expected in late spring.

Sounds very cool!  Please keep me posted, I'd love to see a comparison
like this.

-Urs