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Subjecttime jumps
Hello,

I've written a device driver under 2.0.37. Having acquired a block of
data, the interrupt routine add a timestamp obtained with do_gettimeofday.
In the higher layers, I compute the difference between two consecutive
timestamps to assert there is no missing data.

Most of the time, diff time is 792 millisec, but sometime I find two
sequences, one with 782 millisec, and the other with 802 millisec. The
deviation from normal sequence is 10 millisec, which is also 1/Hz (i386
arch)

I suppose that when my driver, from its interrupt routine, call
do_gettimeofday, there is a timer interrupt pending. Is it something I
could do to be sure the timer interrupt is serviced, if required, before
reading the time ?

Thanks in advance

Pascal A. Dupuis

--
Premature optimization is the root of all evil.
-- D.E. Knuth


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