[Etoys] Slow etoys project loading for EPaati
luke at member.fsf.org
Thu Feb 7 04:23:16 EST 2008
So it seems to have been fairly easy to more than double the speed of
loading our slowest-loading project (names of colors.pr), but I'm not
certain that the fix is correct. The logic seems right but I've
noticed Squeak getting wedged with 100% CPU usage and I'm not sure
whether my change is causing this.
The change is to hack ImageSegment>>restoreEndianness to more
efficiently rehash MethodDictionary objects. MethodDictionary>>rehash
uses #become: and that's expensive -- on my 1.6Ghz machine #become:
takes about 50ms on each of our hundreds of instances. Taking a cue
from the 'Back to the Future' paper [*] it seems like a good idea to
combine all of the #become:'s into a batch so that the heap is only
traversed once, like this:
| newDictionaries |
newDictionaries := oldDictionaries collect: [:d | d rehashWithoutBecome].
oldDictionaries asArray elementsForwardIdentityTo: newDictionaries asArray.
This pulls the loading time of that project on the XO down from 3.5
minutes to 1.5 minutes, which is still too slow but progress is
ChangeSet attached! Can someone who Knows say if it looks right?
-Luke (torn between speed vs. memory profiling next)
P.S. Thanks Bert for the profiling tutorial :-)
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