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Date: Thu, 26 Feb 2015 20:31:09 +0100
Message-ID: <CAPh34md=YbtKmBxG+SpNyTUFoj_VDDfv-sJVn8GCy1dnqwCUbw@mail.gmail.com>
Subject: Re: [PATCH 7/7] x86/intel_rdt: Add CAT documentation and usage guide
From: Hagen Paul Pfeifer <hagen@jauu.net>
To: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        vikas.shivappa@intel.com, matt.fleming@intel.com, hpa@zytor.com,
        tglx@linutronix.de, mingo@kernel.org, tj@kernel.org,
        Peter Zijlstra <peterz@infradead.org>, will.auld@intel.com,
        dave.hansen@intel.com, andi.kleen@intel.com, tony.luck@intel.com,
        kanaka.d.juvva@intel.com
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On 25 February 2015 at 00:16, Vikas Shivappa
<vikas.shivappa@linux.intel.com> wrote:

> +1.2 Why is CAT needed
> +---------------------
> +
> +The CAT  enables more cache resources to be made available for higher
> +priority applications based on guidance from the execution
> +environment.
> +
> +The architecture also allows dynamically changing these subsets during
> +runtime to further optimize the performance of the higher priority
> +application with minimal degradation to the low priority app.
> +Additionally, resources can be rebalanced for system throughput
> +benefit.  (Refer to Section 17.15 in the Intel SDM)
> +
> +This technique may be useful in managing large computer systems which
> +large LLC. Examples may be large servers running  instances of
> +webservers or database servers. In such complex systems, these subsets
> +can be used for more careful placing of the available cache
> +resources.
> +
> +The CAT kernel patch would provide a basic kernel framework for users
> +to be able to implement such cache subsets.

Last paragraph can be deleted. If functionality is merged it is not a
patch anymore.