[time-nuts] FreeBSD, NetBSD, or Minix-III?

Magnus Danielson magnus at rubidium.dyndns.org
Mon May 18 08:03:24 UTC 2009


Hal Murray skrev:
>>> I'm interested in the case where interrupts and scheduling are
>>> enabled so there may be arbitrary gaps inserted into the simple
>>> code.
> 
>> Interrupts enabled means that you can't make it reliable. 
> 
> Sure you can.  Just compare the two high samples and try again if they are 
> different.
> 
> This disadvantage is that you get more jitter on how long it takes to get the 
> answer.  That may be better than taking the overhead of a system call to get 
> into the kernel.

If we are talking about timestamping an interrupt for instance this 
should not be a major issue. For a micro-kernel, things which normally 
go into a device driver should be put in a suitable task.

Cheers,
Magnus



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