[Gc] Re: Problems with GC_size_map

Juan Jose Garcia-Ripoll juanjose.garciaripoll at googlemail.com
Sun Feb 7 13:13:01 PST 2010

On Sun, Feb 7, 2010 at 8:18 AM, Hans Boehm <Hans.Boehm at hp.com> wrote:
>  On Sat, 6 Feb 2010, Juan Jose Garcia-Ripoll wrote:
> The Common Lisp enviroment creates a number of constants at boot time. I
>> think those are the arrays you are seeing. However, those arrays are
>> never changed after creation. It was my understanding that thanks to
>> dirty bits and GC_enable_incremental() the cost of marking those arrays
>> would be close to zero.
>  They will still be traced during full collections, which probably
> won't be that rare.  But they shouldn't be a big deal.  And their
> presence should decrease GC frequency.  Presumably non-nil entries
> are actually pointers or small integers?

These arrays contain either pointers to live objects or NULL. All objects
have been allocated by the garbage collector.

> Since we don't see a blacklisting issue, it might be good to look
> at GC_PRINT_STATS output, and compare to a platform on which it works
> better.  Or possibly compare heap contents on the two platforms.
> But I am suspicious that we're chasing a problem that has already
> been fixed in CVS.

I have built ECL with the garbage collector in a version from CVS. Numbers
are actually worse without changing anything else.


Instituto de Física Fundamental, CSIC
c/ Serrano, 113b, Madrid 28006 (Spain)
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