GC statistics (was Re: big project ported)

[Jonathan P. Olson]

On Wed, 27 Oct 1999, Godmar Back wrote:

>Other things that make Boehm's gc slower is the fact that it's
>noncopying; therefore, its sweep phase complexity is proportional
>to the amount of garbage found.  In other words, it has to spend
>time returned every garbaged object to the allocator one by one.
>
>	- Godmar
>-

In an embedded conservative collector, I do the sweep phase by merely
anding bits in allocation maps.  There's no work to do for each object
being freed, and each word written to the allocation maps can free
up to 32 objects.  In this collector, the mark phase dominates the
collection time, and the sweep phase is always constant.

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Jon Olson, Modular Mining Systems
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