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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)
Date: Fri, 26 Nov 2004 01:34:25 +0100	[thread overview]
Message-ID: <20041126003425.GA5182@elte.hu> (raw)
In-Reply-To: <20041126010841.GA3563@elte.hu>


* 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

  reply	other threads:[~2004-11-27  1:36 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-11-21 20:29 Priority Inheritance Test (Real-Time Preemption) Esben Nielsen
2004-11-22  0:27 ` Ingo Molnar
2004-11-23 13:34   ` Ingo Molnar
2004-11-23 15:47     ` Esben Nielsen
2004-11-23 23:03     ` Esben Nielsen
2004-11-24  3:42       ` Ingo Molnar
2004-11-24  7:51         ` Ingo Molnar
2004-11-24  8:07       ` Ingo Molnar
2004-11-24  8:33         ` Esben Nielsen
2004-11-24  9:55           ` Ingo Molnar
2004-11-24 10:18       ` Ingo Molnar
2004-11-25 15:46         ` Esben Nielsen
2004-11-25 16:58           ` Ingo Molnar
2004-11-25 16:08             ` Esben Nielsen
2004-11-25 17:14               ` Ingo Molnar
2004-11-25 22:08             ` Esben Nielsen
2004-11-26  1:08               ` Ingo Molnar
2004-11-26  0:34                 ` Ingo Molnar [this message]
2004-11-26  0:37                   ` Ingo Molnar
2004-11-26  8:52                     ` Esben Nielsen
2004-11-26 16:26                 ` Esben Nielsen
2004-11-26 20:41                   ` Ingo Molnar
2004-11-26 21:05                     ` Ingo Molnar
2004-11-27 23:05                       ` Esben Nielsen
2004-11-28  8:42                         ` Ingo Molnar
2004-11-28 15:55                           ` Esben Nielsen
2004-11-29  9:59                             ` Ingo Molnar
2004-11-29 15:07                               ` Esben Nielsen
2004-11-29 15:56                                 ` Ingo Molnar
2004-11-29 15:57                                   ` Ingo Molnar
2004-11-29 16:50                                     ` Esben Nielsen
2004-11-30  8:49                                       ` Ingo Molnar
2004-11-22  9:23 ` Bill Huey
2004-11-22 12:37   ` Ingo Molnar
2004-11-22 21:25     ` Bill Huey
2004-11-22 14:16   ` john cooper
2004-11-22 15:24     ` Ingo Molnar
2004-11-23  1:19       ` john cooper
2004-11-23  8:13         ` Esben Nielsen
2004-11-23  9:21         ` Ingo Molnar
2004-11-22 21:30     ` Bill Huey
2004-11-23  1:34       ` john cooper
2004-11-22 16:12   ` Esben Nielsen

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