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From: Peter Zijlstra <peterz@infradead.org>
To: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Cc: Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Juri Lelli <juri.lelli@gmail.com>,
	Luca Abeni <luca.abeni@unitn.it>,
	Steven Rostedt <rostedt@goodmis.org>,
	Claudio Scordino <claudio@evidence.eu.com>,
	Daniel Bistrot de Oliveira <danielbristot@gmail.com>,
	Henrik Austad <henrik@austad.us>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFD] sched/deadline: Support single CPU affinity
Date: Tue, 13 Dec 2016 11:21:35 +0100	[thread overview]
Message-ID: <20161213102135.GJ3124@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <91d96936-7504-1578-d4e8-1f2f8d8dc113@sssup.it>

On Thu, Nov 10, 2016 at 11:01:59AM +0100, Tommaso Cucinotta wrote:
> 
> Just a note: if you want to recover arbitrary task affinities, you can re-cast your above test like this:
> 
> for_each_processor(cpu)
>   \sum U[t]/A[t] \leq 1 (or U_max), for each task t on cpu, with utilization U[t] and A[t] tasks overall in its affinity mask
> 

Do I read it correct when I interpret A[t] as the number of CPUs in its
affinity mask?

For A[t] == 1, that reduces to the UP case:

	\Sum U[t] \leq 1

and A[t] = N that reduces to the G-EDF case:

	\Sum U[t] \leq N


Also, does recoverable mean a bound tardiness, or is that something
weaker still?

  reply	other threads:[~2016-12-13 10:21 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-10  8:08 [RFD] sched/deadline: Support single CPU affinity Peter Zijlstra
2016-11-10  9:06 ` luca abeni
2016-11-10 10:59   ` Peter Zijlstra
2016-11-10 12:27     ` luca abeni
2016-11-10 11:03   ` Tommaso Cucinotta
2016-11-10 14:34     ` luca abeni
2016-11-10 10:01 ` Tommaso Cucinotta
2016-12-13 10:21   ` Peter Zijlstra [this message]
2016-12-15 11:30     ` Tommaso Cucinotta
2016-12-15 12:16       ` Peter Zijlstra
2016-11-10 12:21 ` Henrik Austad
2016-11-10 12:38   ` luca abeni
2016-11-10 12:56     ` Henrik Austad
2016-11-10 14:23       ` luca abeni
2016-11-10 12:56   ` Peter Zijlstra

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