From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH 0/5] Intel Code/Data Prioritization(CDP) feature enabling Date: Wed, 2 Sep 2015 13:08:33 +0100 Message-ID: <55E6E6C1.5050906@citrix.com> References: <1441182482-7688-1-git-send-email-he.chen@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZX6qF-0004he-K0 for xen-devel@lists.xenproject.org; Wed, 02 Sep 2015 12:08:39 +0000 In-Reply-To: <1441182482-7688-1-git-send-email-he.chen@linux.intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: He Chen , xen-devel@lists.xenproject.org Cc: wei.liu2@citrix.com, ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, ian.jackson@eu.citrix.com, jbeulich@suse.com, keir@xen.org List-Id: xen-devel@lists.xenproject.org On 02/09/15 09:27, He Chen wrote: > Hi all, > > Code/Data Prioritization(CDP) is offered in Intel Broadwell and later server > platforms, which is an extension of CAT. CDP enables isolation and separate > prioritization of code and data fetches to the L3 cache in a software > configurable manner, which can enable workload prioritization and tuning of > cache capacity to the characteristics of the workload. CDP extends Cache > Allocation Technology (CAT) by providing separate code and data capacity bit > masks(CBM) per Class of Service (COS). CDP is used on VM basis in the Xen > implementation. > > More information about CDP, please refer to Intel SDM, Volumn 3, section 17.16 > http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-manual-325462.pdf > > This patch series enables CDP feature in Xen based on CAT code, including > extending CBM operation functions and introducing new commands to enable/disable > CDP dynamically. For all the changes, please see in each patch. > > This patchset has been tested on Intel Broadwell server platform. > > To make this patchset better, any comment or suggestion is welcomed, I would > really appreciate it. I have taken a look at patches 1-3. For the most part, it looks good. The main point I have is on patch 2, as to whether it is sensible to permit enabling/disabling cdp at runtime. I suggest that it is not sensible, and should be a command line parameter instead. If this is agreed as ok going forwards, patches 3 through 5 should become rather more simple. ~Andrew