Date: Fri, 13 Nov 2015 15:33:04 -0200
From: Marcelo Tosatti <mtosatti@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vikas Shivappa <vikas.shivappa@intel.com>, Tejun Heo <tj@kernel.org>,
        Yu Fenghua <fenghua.yu@intel.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] ioctl based CAT interface
Message-ID: <20151113173303.GB13490@amt.cnet>
References: <20151113163933.GA10222@amt.cnet>
 <20151113165100.GI17308@twins.programming.kicks-ass.net>
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On Fri, Nov 13, 2015 at 05:51:00PM +0100, Peter Zijlstra wrote:
> On Fri, Nov 13, 2015 at 02:39:33PM -0200, Marcelo Tosatti wrote:
> > + * 	* one tcrid entry can be in different locations 
> > + * 	  in different sockets.
> 
> NAK on that without cpuset integration.
> 
> I do not want freely migratable tasks having radically different
> performance profiles depending on which CPU they land.

Ok, so, configuration:


Socket-1				Socket-2

pinned thread-A with			100% L3 free
80% of L3 
reserved


So it is a problem if a thread running on socket-2 is scheduled to 
socket-1 because performance is radically different, fine.

Then one way to avoid that is to not allow freely migratable tasks
to move to Socket-1. Fine.

Then you want to use cpusets for that.

Can you fill in the blanks what is missing here?

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