Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933304AbdCGUlq (ORCPT ); Tue, 7 Mar 2017 15:41:46 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:43723 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756238AbdCGUli (ORCPT ); Tue, 7 Mar 2017 15:41:38 -0500 Date: Tue, 7 Mar 2017 21:22:04 +0100 (CET) From: Thomas Gleixner To: "Luck, Tony" cc: Vikas Shivappa , "Shivappa, Vikas" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "hpa@zytor.com" , "mingo@kernel.org" , "peterz@infradead.org" , "Shankar, Ravi V" , "Yu, Fenghua" , "Kleen, Andi" , "davidcc@google.com" , "eranian@google.com" Subject: RE: [PATCH 1/1] x86/cqm: Cqm requirements In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F6120F0A9@ORSMSX113.amr.corp.intel.com> Message-ID: References: <1488908964-30261-1-git-send-email-vikas.shivappa@linux.intel.com> <3908561D78D1C84285E8C5FCA982C28F6120F0A9@ORSMSX113.amr.corp.intel.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 821 Lines: 23 On Tue, 7 Mar 2017, Luck, Tony wrote: > > That's all nice and good, but I still have no coherent explanation why > > measuring across allocation domains makes sense. > > Is this in reaction to this one? > > >> 5) Put multiple threads into a single measurement group > > If we fix it to say "threads from the same CAT group" does it fix things? > > We'd like to have measurement groups use a single RMID ... if we > allowed tasks from different CAT groups in the same measurement > group we wouldn't be able to split the numbers back to report the > right overall total for each of the CAT groups. Right. And the same applies to CPU measurements. If we have threads from 3 CAT groups running on a CPU then the aggregate value (except for bandwidth which can be computed by software) is useless. Thanks, tglx