[Twisted-Python] Accurate delays in callLater

Norm Petterson njp at njp.us
Thu Jun 23 14:27:20 EDT 2005

Sébastien Pierre wrote:

> Hi !
> Le 23 juin 05 à 19:30, Bob Ippolito a écrit :
>> Additionally, the precision of reactor.callLater is only as good as  
>> the precision of the reactor's primitive for timing (select, in the  
>> default reactor).  The precision of select varies widely based on  
>> the platform.
>> You might have more luck with twisted.internet.task.LoopingCall
> This makes me want to ask if Twisted is able to run "smooth real  
> time" processes. Say for instance that I have to run a process every  
> second (with a precision of 0.1s). Can I be sure that after having  
> run for 1 hours the process will have been executed 3600 times ? same  
> for 1 day, 1 week, etc ?
Based on  
I've been using twisted.internet.task.LoopingCall for applications 
calling for 1 second (or 2 second, or 10 second, etc.) indefinite 
repetition for the past year, and have noted minor slippage that I 
attribute to *not* bumping the twisted application process priority 
above its default on the platforms involved (Linux/DEC Alpha, W2K/Intel 
P4). If the slippage were unacceptable, I'd try raising process priority 
before anything else...


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