[Vm-dev] Suspend

John M McIntosh johnmci at smalltalkconsulting.com
Wed Jul 18 19:27:37 UTC 2007


That is what the getNextWakeupTick() does, it returns the time the vm  
has to wakeup to service the next delay since at that point all  
processes
are:

(a) waiting on a semaphore
(b) waiting on a Delay to terminate in the future which is found via  
getNextWakeupTick()


On Jul 18, 2007, at 12:15 PM, tim Rowledge wrote:

> While the subject is in the air, perhaps it would be worth  
> considering what the ideal situation would be.
>
> For example, I would suggest we might drop the idea of a suspend- 
> for-a-fixed-time and have a suspend until next alarm. That would be  
> called by the background process when nothing else wants time and  
> would suspend the vm until the time specified by the timer queue;  
> perhaps some emergency backstop value might be used in case some  
> twerp gets us into a state with no timer active and no Process  
> doing anything. That ought to remove the problem of looping on a  
> tiny delay, though if certain OSs can't sleep for very short  
> periods I have no idea how they can do much at that point.
>
> OSs that have suitable asynchronous or interrupt driven input stuff  
> can trigger the return from the suspend at need. OSs that don't  
> (the only one I know of is RISC OS right now and I'll almost  
> certainly be retiring from maintaining that soon) can probably set  
> some vm-internal polling.
>
> I'm sure it would require some changes in the image to make this  
> work properly but so what. Older images can run on older vms.
>
> tim
> --
> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
> Shift to the left!  Shift to the right!  Pop up, push down, byte,  
> byte, byte!
>
>

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