I was doing some test on interrupt latency (time from raising an
interrupt to reading timestamp
in a handler). I created my own fast handler registered at IRQ32 (
interrupt is generated by
the APIC timer on a Ppro 200) that gives me a latency of approx 2300
nanoseconds
However, approx every 30 seconds this latency shoots up to 15000ns or so
and shows 4 instances
of that and then goes back to 2000ns.. I was wondering if anyone knows
what this could be
due to.
I applied the RT-Linux patch, and I still see it (rt-linux should
disable all the cli()'s
in the kernel source) so.. i am quite perplexed as to where this is
coming from.
The most interesting thing it is perfectly periodic.
If anyone wants to see a plot (over 500secs).. I could send it to you
with an FFT :)
Would greatly appreciate any hints :)
Thanks
Manoj Apte
===========================================================================
MANOJ APTE
Computer Science
email: manoj@erc.msstate.edu
phone: (601)-325-2476 (off) ENGINEERING RESEARCH
CENTER.
(601)-323-8160 (res) Mississippi State
University.
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