From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Xu, Dongxiao" Subject: Re: Xen Platform QoS design discussion Date: Thu, 29 May 2014 07:31:24 +0000 Message-ID: <40776A41FC278F40B59438AD47D147A911A20944@SHSMSX104.ccr.corp.intel.com> References: <40776A41FC278F40B59438AD47D147A9119F3FEA@SHSMSX104.ccr.corp.intel.com> <5363804B020000780000E604@mail.emea.novell.com> <40776A41FC278F40B59438AD47D147A9119F4EF4@SHSMSX104.ccr.corp.intel.com> <5363AE54020000780000E7A2@mail.emea.novell.com> <40776A41FC278F40B59438AD47D147A9119FE6BB@SHSMSX104.ccr.corp.intel.com> <5368B418.9000307@citrix.com> <536AA342.8030003@citrix.com> <40776A41FC278F40B59438AD47D147A911A00A4C@SHSMSX104.ccr.corp.intel.com> <536B69AB.7010005@citrix.com> <40776A41FC278F40B59438AD47D147A911A150FC@SHSMSX104.ccr.corp.intel.com> <537A0B17020000780001390F@mail.emea.novell.com> <5379F576.4050108@eu.citrix.com> <537A18260200007800013A06@mail.emea.novell.com> <40776A41FC278F40B59438AD47D147A911A1AAEC@SHSMSX104.ccr.corp.intel.com> <537DD3E60200007800014CFD@mail.emea.novell.com> <537DC2F2.30702@eu.citrix.com> <40776A41FC278F40B59438AD47D147A911A206A4@SHSMSX104.ccr.corp.intel.com> <5386E96402000078000B525D@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5386E96402000078000B525D@mail.emea.novell.com> Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich , "george.dunlap@eu.citrix.com" Cc: "andrew.cooper3@citrix.com" , "Auld, Will" , "Ian.Campbell@citrix.com" , "Nakajima, Jun" , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org > -----Original Message----- > From: Jan Beulich [mailto:jbeulich@suse.com] > Sent: Thursday, May 29, 2014 3:02 PM > To: george.dunlap@eu.citrix.com; Xu, Dongxiao > Cc: andrew.cooper3@citrix.com; Ian.Campbell@citrix.com; > xen-devel@lists.xen.org > Subject: Re: RE: [Xen-devel] Xen Platform QoS design discussion > > >>> "Xu, Dongxiao" 05/29/14 2:46 AM >>> > >I think Jan's opinion here is similar to what I proposed in the beginning of this > thread. > >The only difference is that, Jan prefers to get the CQM data per-socket and > per-domain > >with data copying, while I proposed to get the CQM data per-domain for all > sockets > >that can reduce the amount of hypercalls. > > I don't think I ever voiced any preference between these two. All I said it > depends on > prevalent usage models, and to date I don't think I've seen a proper analysis of > what > the main usage model would be - it all seems guesswork and/or taking random > examples. > > What I did say I'd prefer is to have all this done outside the hypervisor, with the > hypervisor just providing fundamental infrastructure (MSR accesses). Okay. If I understand correctly, you prefer to implement a pure MSR access hypercall for one CPU, and put all other CQM things in libxc/libxl layer. In this case, if libvert/XenAPI is trying to query a domain's cache utilization in the system (say 2 sockets), then it will trigger _two_ such MSR access hypercalls for CPUs in the 2 different sockets. If you are okay with this idea, I am going to implement it. Thanks, Dongxiao > > Jan