Date: Fri, 26 Nov 2004 01:34:25 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Esben Nielsen <simlo@phys.au.dk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Priority Inheritance Test (Real-Time Preemption)
Message-ID: <20041126003425.GA5182@elte.hu>
References: <20041125165829.GA24121@elte.hu> <Pine.OSF.4.05.10411252305040.25041-100000@da410.ifa.au.dk> <20041126010841.GA3563@elte.hu>
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* 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.

	Ingo
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