I've added logic to allow you to alter quartz flush logic and post  
flush logic ms times. In the info.plist within the application you  
will find 4 keys which alter this behavior.

SqueakUIFlushPrimaryDeferNMilliseconds = 20

Attempt to accumulate draw events in a 20 ms window. If a draw occurs  
and the time is greater than 20 ms from the   last draw we draw and  
flush. If the draw is in the 20ms window we draw, and do a CGSync  
(once) and do not do the flush.  The sync should schedule an flush by  
the carbon event handler within 20ms or so. Setting this value  
towards 0 will flush on every draw. I will note setting to 16ms  
causes the hilbert test to draw each pixel, versus clumps of pixels.   
Altering this value will affect the frame rate of your squeak animation.

SqueakUIFlushSecondaryCheckForPossibleNeedEveryNMilliseconds = 20

Check no faster than 20 ms for possible pending flush events. This  
reduces CPU overhead. The value of this key has a relationship to the  
other two keys, but making it smaller might not improve thing.  
Because of how the  checking is done there is no guarantee it will  
achieve a rate under say 16ms, but it will always occur within N  
seconds. This value can effect how menus item highlighting is done.

  SqueakUIFlushSecondaryCleanupDelayMilliseconds = 25

When N ms occur based on  
SqueakUIFlushSecondaryCheckForPossibleNeedEveryNMilliseconds and we  
have a flush pending and the flush has not occurred within this key  
value of 25ms we force a flush. This value should be more than  
SqueakUIFlushPrimaryDeferNMilliseconds to avoid conflicts with the  
draw loop.  If for example we have a draw and a draw then no further  
drawing, the first draw should be flushed, then next cached for  
upwards of 20-40ms based on  
SqueakUIFlushSecondaryCheckForPossibleNeedEveryNMilliseconds then we  
would see it exceeds this key value and cause the flush.

SqueakUIFlushUseHighPercisionClock =  true

Use a more expensive ms accurate clock when set to true. If false we  
use the 16ms based cheap clock. This is set to true to give higher  
accuracy and does not seem to affect CPU usage based on statistical  
sampling of production VMs.

Squeakers are welcome to alter these values to obtain best behaviour  
which might change based on versions of OS-X.

Note:
Altering SqueakUIFlushPrimaryDeferNMilliseconds will affect frame rate.
Altering SqueakUIFlushSecondaryCheckForPossibleNeedEveryNMilliseconds  
& SqueakUIFlushSecondaryCleanupDelayMilliseconds will affect menu  
drawing.


Feedback about these choices is welcome.


This VM can be found at
ftp.smalltalkconsulting.com
Squeak 3.8.8beta14.app.zip

I've also moved a copy of the sit files to my idisk
http://homepage.mac.com/johnmci/FileSharing.html

--
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John M. McIntosh <johnmci at smalltalkconsulting.com> 1-800-477-2659
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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