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    SubjectRe: PREEMPT_RT vs ADEOS: the numbers, part 1

    * Karim Yaghmour <> wrote:

    > Ingo Molnar wrote:
    > > how were interrupt response times measured, precisely? What did the
    > > target (measured) system have to do to respond to an interrupt? Did you
    > > use the RTC to measure IRQ latencies?
    > The logger used two TSC values. One prior to shooting the interrupt to
    > the target, and one when receiving the response. Responding to an
    > interrupt meant that a driver was hooked to the target's parallel port
    > interrupt and simply acted by toggling an output pin on the parallel
    > port, which in turn was hooked onto the logger's parallel port in a
    > similar fashion. We'll post the code for all components (both logger
    > and target) for everyone to review. There's no validity in any tests
    > if others can't analyze/criticize/ duplicate.

    ok, this method should work fine. I suspect you increased the parport
    IRQ's priority to the maximum on the PREEMPT_RT kernel, correct? Was
    there any userspace thread on the target system (receiving the parport
    request and sending the reply), or was it all done in a kernelspace
    parport driver?

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      Last update: 2005-06-12 08:42    [W:0.020 / U:18.460 seconds]
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