Re: Priority Inheritance Test (Real-Time Preemption)

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> 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.

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/