Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753129AbbG2UHu (ORCPT ); Wed, 29 Jul 2015 16:07:50 -0400 Received: from mga02.intel.com ([134.134.136.20]:51781 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbbG2UHt (ORCPT ); Wed, 29 Jul 2015 16:07:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,572,1432623600"; d="scan'208";a="757643954" Date: Wed, 29 Jul 2015 13:07:30 -0700 (PDT) From: Vikas Shivappa X-X-Sender: vikas@vshiva-Udesk To: "Auld, Will" cc: "Shivappa, Vikas" , Marcelo Tosatti , Vikas Shivappa , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , "hpa@zytor.com" , "tglx@linutronix.de" , "mingo@kernel.org" , "tj@kernel.org" , "peterz@infradead.org" , "Fleming, Matt" , "Williamson, Glenn P" , "Juvva, Kanaka D" Subject: RE: [PATCH 3/9] x86/intel_rdt: Cache Allocation documentation and cgroup usage guide In-Reply-To: <96EC5A4F3149B74492D2D9B9B1602C27461EB932@ORSMSX105.amr.corp.intel.com> Message-ID: References: <1435789270-27010-1-git-send-email-vikas.shivappa@linux.intel.com> <1435789270-27010-4-git-send-email-vikas.shivappa@linux.intel.com> <20150728231516.GA16204@amt.cnet> <96EC5A4F3149B74492D2D9B9B1602C27461EB932@ORSMSX105.amr.corp.intel.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1430 Lines: 43 On Tue, 28 Jul 2015, Auld, Will wrote: > > >> -----Original Message----- >> >> Same comment as above - Cgroup masks can always overlap and other cgroups >> can allocate the same cache , and hence wont have exclusive cache allocation. > > [Auld, Will] You can define all the cbm to provide one clos with an exclusive area Do you mean a CLOS that has all the bits set. We donot support exclusive area today. The bits in the mask can overlap .. hence can always share the same cache allocation . > >> >> So natuarally the cgroup with tasks would get to use the cache if it has the same >> mask (say representing 50% of cache in your example) as others . > > [Auld, Will] automatic adjustment of the cbm make me nervous. There are times > when we want to limit the cache for a process independent of whether there is > lots of unused cache. > Please see example below - In general , I just mean the cache mask can have bits that can overlap - does not matter whether there is tasks in it or not. > >> (assume there are 8 bits max cbm) >> cgroupa - mask - 0xf >> cgroupb - mask - 0xf . Now if cgroupa has no tasks , cgroupb naturally gets all >> the cache. >> >> Thanks, >> Vikas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/