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Subjectgeneral timing question

Suppose that I have a process that generates a timestamp every time it
loops through some task, and assume that this process is not running with
real time support. Is there any way to guarantee that the timestamping
will be accurate to within some bound? That is, my task ends at some
absolute time t0, and my timestamp gets assigned some short time t1 after
t0 (if there is a context switch before the timestamp is assigned then the
delay will be greater I guess). So, is there any way to bound t1-t0?

My guess is that trying to _guarantee_ that t1-t0 < n for some n would
be useless since my process could get swapped out with some higher
priority process, or a bunch of interrupts happen, etc. But on _average_
what would n be? It would be related to the processor speed, the machine
load, and the jiffie that has been compiled into the machine correct?

Michael B. Rash
http://www.math.umd.edu/~mbr



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