At 9:28 AM -0800 2/9/01, John M McIntosh wrote:
>  > They're still polled. The key issue in the VM event stuff was not 
>loose user
>>  input events anymore.
>
>The problem I've seen is that events sometimes *do* get lost, but in 
>the image, not between the image and the VM.  The 'place' they get
>lost seems to be the same place that is responsible for at least some
>of the sluggishness.
>

Late last night I built a mac os 9. version of Squeak that uses the 
macintosh threadsLib library, which is a light weight cooperative 
thread model not a heavy one like pthreads. It only took a few lines 
of code, and passed the smoke test on the first try, at which point I 
went to bed. However I've some more reading to do about if this is a 
good thing. Since it is a cooperative model there are less worries 
about a thread loosing control at the wrong time and having a 
collision with data being manipulated by another thread.

For the Mac OS the thread manager assumes the main thread is the 
event handler, and stuff happens in secondary threads. So I do this

     createNewThread();
     while(true)
         {
         ioProcessEvents();
	YieldToAnyThread();
         }

The interp() thread Yields to the event thread at ioGetNextEvent if 
there isn't any events in the queue and I think every 1/2 second in 
checkForInterrupts. Also the thread scheduler does attempt to 
schedule the main thread if an OS event is pending which can happen 
at some other undocumented scheduling points.

It may also greatly improve some messy issues with the browser 
plugin, however I'm going to have a few people kick the tires first, 
and given other comments I'm not sure where the slowdown is. But I'm 
looking.
-- 
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John M. McIntosh <johnmci at smalltalkconsulting.com> 1-800-477-2659
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Custom Macintosh programming & various Smalltalk dialects
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