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Date: Mon, 23 Jan 2017 12:30:09 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: David Carrillo-Cisneros <davidcc@google.com>,
        Vikas Shivappa <vikas.shivappa@linux.intel.com>,
        Vikas Shivappa <vikas.shivappa@intel.com>,
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        "Shankar, Ravi V" <ravi.v.shankar@intel.com>,
        "Luck, Tony" <tony.luck@intel.com>, Fenghua Yu <fenghua.yu@intel.com>,
        andi.kleen@intel.com, "H. Peter Anvin" <h.peter.anvin@intel.com>
Subject: Re: [PATCH 00/12] Cqm2: Intel Cache quality monitoring fixes
Message-ID: <20170123113009.GW6485@twins.programming.kicks-ass.net>
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On Mon, Jan 23, 2017 at 10:47:44AM +0100, Thomas Gleixner wrote:
> So again: 
> 
>   Can please everyone involved write up their specific requirements
>   for CQM and stop spamming us with half baken design proposals?
> 
>   And I mean abstract requirements and not again something which is
>   referring to existing crap or some desired crap.
> 
> The complete list of requirements has to be agreed on before we talk about
> anything else.

So something along the lines of:

 A) need to create a (named) group of tasks
   1) group composition needs to be dynamic; ie. we can add/remove member
      tasks at any time.
   2) a task can only belong to _one_ group at any one time.
   3) grouping need not be hierarchical?

 B) for each group, we need to set a CAT mask
   1) this CAT mask must be dynamic; ie. we can, during the existence of
      the group, change the mask at any time.

 C) for each group, we need to monitor CQM bits
   1) this monitor need not change


Supporting Use-Cases:

A.1: The Job (or VM) can have a dynamic task set
B.1: Dynamic QoS for each Job (or VM) as demand / load changes



Feel free to expand etc..