Messages in this thread | | | Date | Fri, 26 Nov 2004 01:37:13 +0100 | From | Ingo Molnar <> | Subject | Re: Priority Inheritance Test (Real-Time Preemption) |
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* 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.
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