Re: Garbage collector necessary (for Ada access types)?

[pipex!uknet!root44!hrc63!mrcu!paj@uunet.uu.net (Paul Johnson)]

In article <C6L3wx.6wD.1@cs.cmu.edu> monnier+@cs.cmu.edu (Stefan Monnier) write
s:

>If you don't want to spend too much time in your compiler just for the
>GC problem (emitting code so that the GC knows what is a pointer andwhat
>is not), you can use a conservative GC (you can even use 'ready-to-go'
>ones for C: it replaces the malloc and the mfree becomes useless). But
>beware its limitations: such GC is generally slower and doesn't guarantee
>you won't have "memory leaks".

I have a paper by Ben Zorn of the U of Colorado at Boulder.  He
measured the performance of the Boehm conservative GC in half a dozen
programs and found that the slowdown was pretty trivial, although the
programs did need about twice as much memory.

The full report is CU-CS-573-92, April 1992, from Dept of Computer
Science, Campus box 430, University of Colorado, Boulder, Colorado
80309.

Of course, a well tuned GC that has structure information available
will do much better.  For a good survey of GC techniques, see
"Uniprocessor Garbage Collection Techniques" by Paul R. Wilson, U. of
Texas.  <wilson@cs.utexas.edu>.  This paper is available by FTP, so
try Archie before mailing Dr. Wilson.


Paul.
-- 
Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
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