[squeak-dev] Re: Socket clock rollover issues

John M McIntosh johnmci at smalltalkconsulting.com
Wed Apr 29 01:35:15 UTC 2009


On 28-Apr-09, at 6:24 PM, Andreas Raab wrote:

> Nicolas Cellier wrote:
>> I wonder why you adopt a soft busy loop like this:
>> 	"Wait in a soft busy-loop (500ms) to avoid msecs-rollover issues"
>> 	self writeSemaphore waitTimeoutMSecs:
>> 		(deadline - Time millisecondClockValue min: 500 max: 0)
>
> Heh. You are asking about my dirty little secrets ;-) The reason for  
> writing the loop that way is that I have (mounting) evidence that at  
> times we may loose signals originating from external semaphores. We  
> have seen situations where external signals apparently weren't  
> delivered even though the condition was clearly set on the  
> underlying socket. This is not only true for sockets but we have  
> seen other situations when external semaphore signals apparently  
> have been delivered.

Er, so given we don't have a thread safe signalSemaphoreWithIndex code  
base (on purpose) I wonder how many signals per second are you doing  
and are you perhaps
overflowing the semaphoresUseBufferA/B table? Assuming you are saying  
you do the signalSemaphoreWithIndex() and you never see that over in  
the image?

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John M. McIntosh <johnmci at smalltalkconsulting.com>   Twitter:   
squeaker68882
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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