From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH 0/4] enable Memory Bandwidth Monitoring (MBM) for VMs Date: Tue, 23 Dec 2014 15:47:35 +0000 Message-ID: <54998E97.5070608@citrix.com> References: <1419324880-13212-1-git-send-email-chao.p.peng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1419324880-13212-1-git-send-email-chao.p.peng@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: Chao Peng , xen-devel@lists.xen.org Cc: keir@xen.org, Ian.Campbell@citrix.com, stefano.stabellini@eu.citrix.com, Ian.Jackson@eu.citrix.com, JBeulich@suse.com, wei.liu2@citrix.com List-Id: xen-devel@lists.xenproject.org On 23/12/2014 08:54, Chao Peng wrote: > Intel Memory Bandwidth Monitoring(MBM) is a new hardware feature > which builds on the CMT infrastructure to allow monitoring of system > memory bandwidth. Event codes are provided to monitor both "total" > and "local" bandwidth, meaning bandwidth over QPI and other external > links can be monitored. > > For XEN, MBM is used to monitor memory bandwidth for VMs. Due to its > dependency on CMT, the software also makes use of most of CMT codes. > Actually, besides introducing two additional events and some cpuid > feature bits, there are no extra changes compared to cache occupancy > monitoring in CMT. Due to this, CMT should be enabled first to use > this feature. > > For interface changes, the patch serial only introduces a new command > "XEN_SYSCTL_PSR_CMT_get_l3_event_mask" which exposes MBM feature > capability to user space and introduces two additional options for > "xl psr-cmt-show": > total_mem_bandwidth: Show total memory bandwidth > local_mem_bandwidth: Show local memory bandwidth > > The usage flow keeps the same with CMT. > > Chao Peng (4): > x86: expose CMT L3 event mask to user space > tools: libxc: add routine to get CMT L3 event mask > tools: libxl: code preparation for MBM > tools: add total/local memory bandwith monitoring Please can you add a note about MBM in the command line documentation, beside the CMT information. ~Andrew