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    SubjectRe: Priority Inheritance Test (Real-Time Preemption)

    * Ingo Molnar <mingo@elte.hu> wrote:

    >
    > * Ingo Molnar <mingo@elte.hu> wrote:
    >
    > > the additional +1 msec comes from the fact that 1-deep lock/unlock of
    > > lock1 is an allowed operation too - 2 msec would be the limit if the
    > > only sequence is the 2-deep one.
    > >
    > > so i think the numbers, at least in the 2-deep case, are quite close
    > > to the theoretical boundary.
    >
    > in the generic case i think the theoretical boundary should be something
    > like:
    >
    > sum(i=1...n)(i) == (n+1) * n / 2
    >
    > n=1 limit=1
    > n=2 limit=3
    > n=3 limit=6
    > n=4 limit=10
    >
    > this is quite close to what you have measured for n=1,2,3, and i think
    > it's becoming exponentially harder to trigger the worst-case with higher
    > N, so the measured results will likely be lower than that.

    also, you might want to try the simpler N-deep-locking-only variant,
    where the maximum latency should be 'n'. This likely needs some changes
    to the blocker.c code though - i.e. set 'max' always to lock_depth.

    Ingo
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