Array new: 1000000 performance question

jhkeel jhkeel at facstaff.wisc.edu
Tue Jul 20 16:38:28 UTC 2004


--- In squeak at yahoogroups.com, Marcus Denker <denker at i...> wrote:
> 
> This shows nicely how the garbagecollector works. After starting up, VM 
> Statistics (you
....
> (wie call this "incremental GC"). So after the Array was allocated, the 
> incremental
> GC has to clean a huge young space (over 4MB), which takes time.

Marcus,
Thanks for the informative response.  
 
The VM stats also explained why if I allocate 5 large objects the cpu time did not increase 
any more than one object.  The stats show that a Full GC was automatically triggered 
before or during the allocation.  I was guessing that more large objects would increase the 
CPU but I wasn't seeing  it happen.

However, with an idle Squeak, it took over 20 minutes on the 3Ghz PC before cpu usage 
dropped from 12% back to 2% (Seems to be "infinite" on the G3 to drop from 35-50% to 9% 
- well, longer than I could wait, anyhow).  Seems to this G3 owner that this algorithm 
could be improved some :)  Maybe I'll look at it if I get a moment.

Thanks,
Jack






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