From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751364AbdBBAfX (ORCPT <rfc822;w@1wt.eu>);
        Wed, 1 Feb 2017 19:35:23 -0500
Received: from mga14.intel.com ([192.55.52.115]:2300 "EHLO mga14.intel.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751088AbdBBAfW (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 1 Feb 2017 19:35:22 -0500
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.33,322,1477983600"; 
   d="scan'208";a="1089864252"
From: Andi Kleen <andi@firstfloor.org>
To: "Luck\, Tony" <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
        David Carrillo-Cisneros <davidcc@google.com>,
        Vikas Shivappa <vikas.shivappa@linux.intel.com>,
        "Shivappa\, Vikas" <vikas.shivappa@intel.com>,
        Stephane Eranian <eranian@google.com>,
        linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
        "hpa\@zytor.com" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
        "Peter Zijlstra" <peterz@infradead.org>,
        "Shankar\, Ravi V" <ravi.v.shankar@intel.com>,
        "Yu\, Fenghua" <fenghua.yu@intel.com>,
        "Kleen\, Andi" <andi.kleen@intel.com>,
        "Anvin\, H Peter" <h.peter.anvin@intel.com>
Subject: Re: [PATCH 00/12] Cqm2: Intel Cache quality monitoring fixes
References: <alpine.DEB.2.20.1701180905130.3464@nanos>
        <1484879563-29977-1-git-send-email-vikas.shivappa@linux.intel.com>
        <CALcN6mhcoTk7JT3ixSLCOHFVq4v0_j4wfHW4onhDYupOXfpGJA@mail.gmail.com>
        <alpine.DEB.2.20.1701201053350.3602@nanos>
        <CALcN6mjjAhinhKW_PtQhBNA6N3wLL=BkrrJ3oX5++M_cQuF-uQ@mail.gmail.com>
        <alpine.DEB.2.20.1701231013360.3836@nanos>
        <3908561D78D1C84285E8C5FCA982C28F3A2A8947@ORSMSX114.amr.corp.intel.com>
Date: Wed, 01 Feb 2017 16:35:21 -0800
In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F3A2A8947@ORSMSX114.amr.corp.intel.com>
        (Tony Luck's message of "Wed, 1 Feb 2017 20:08:08 +0000")
Message-ID: <87inotjupi.fsf@firstfloor.org>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

"Luck, Tony" <tony.luck@intel.com> writes:
> 9)	Measure per logical CPU (pick active RMID in same precedence for task/cpu as CAT picks CLOSID)
> 10)	Put multiple CPUs into a group

I'm not sure this is a real requirement. It's just an optimization,
right? If you can assign policies to threads, you can implicitly set it
per CPU through affinity (or the other way around).
The only benefit would be possibly less context switch overhead,
but if all the thread (including idle) assigned to a CPU have the
same policy it would have the same results.

I suspect dropping this would likely simplify the interface significantly.

-Andi