[squeak-dev] Re: Image normalization

Bert Freudenberg bert at freudenbergs.de
Wed Sep 17 18:00:55 UTC 2008


Am 17.09.2008 um 19:37 schrieb Eliot Miranda:

> You know that's not how the GC works in incremental (high frequency)  
> mode, right?  The GC starts from young space using the rootTable as  
> roots.

Yes I know.

> Further, when the GC does a full GC it does a full trace (necessary)  
> but only compacts from the lowest free.  You could easily simulate  
> perm space simply by adding a new generation, e.g. middleAgedStart.

Perhaps, though I'm not sure about the "easily" part ;)

The problem with a full GC is the mark bits, which are stored with the  
object so every last page in memory is marked dirty even for objects  
not modified (wouldn't you wish for an object table?)

>  But the store check would be 1 comparison against a global more  
> expensive (i.e. nearly twice as expensive, at least in code size).

Unless someone has a brilliant idea, yes :/

- Bert -





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