From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752763AbbAGMQX (ORCPT ); Wed, 7 Jan 2015 07:16:23 -0500 Received: from casper.infradead.org ([85.118.1.10]:33615 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752038AbbAGMQW (ORCPT ); Wed, 7 Jan 2015 07:16:22 -0500 Date: Wed, 7 Jan 2015 13:16:17 +0100 From: Peter Zijlstra To: Matt Fleming Cc: Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Andi Kleen , Thomas Gleixner , linux-kernel@vger.kernel.org, "H. Peter Anvin" , Kanaka Juvva , Matt Fleming Subject: Re: [PATCH v4 10/11] perf/x86/intel: Perform rotation on Intel CQM RMIDs Message-ID: <20150107121617.GF25325@worktop.programming.kicks-ass.net> References: <1415999712-5850-1-git-send-email-matt@console-pimps.org> <1415999712-5850-11-git-send-email-matt@console-pimps.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1415999712-5850-11-git-send-email-matt@console-pimps.org> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 14, 2014 at 09:15:11PM +0000, Matt Fleming wrote: + /* > + * A reasonable upper limit on the max threshold is the number > + * of lines tagged per RMID if all RMIDs have the same number of > + * lines tagged in the LLC. > + * > + * For a 35MB LLC and 56 RMIDs, this is ~1.8% of the LLC. > + */ > + __intel_cqm_max_threshold = > + boot_cpu_data.x86_cache_size * 1024 / (cqm_max_rmid + 1); Seeing how a percentage is without unit, the 35MB figure seems pointless. Also, why would a flat distribution be a good measure for 'empty'? I would think that would in fact constitute in use. Should we make this 1/16th of this figure or any other random fraction < 1 ?