From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH v4 00/10] VM Power Management Date: Tue, 28 Oct 2014 16:21:02 +0100 Message-ID: <1804867.TWdiCQc2JQ@xps13> References: <1412003903-9061-1-git-send-email-alan.carew@intel.com> <3349663.LNtcecTXb3@xps13> <0E29434AEE0C3A4180987AB476A6F6306D2811AD@IRSMSX109.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev-VfR2kkLFssw@public.gmane.org To: "Carew, Alan" Return-path: In-Reply-To: <0E29434AEE0C3A4180987AB476A6F6306D2811AD-kPTMFJFq+rHjxeytcECX8bfspsVTdybXVpNB7YpNyf8@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" Hi Alan, Did you make any progress in Qemu/KVM community? We need to be sync'ed up with them to be sure we share the same goal. I want also to avoid using a solution which doesn't fit with their plan. Remember that we already had this problem with ivshmem which was planned to be dropped. Thanks -- Thomas 2014-10-16 15:21, Carew, Alan: > Hi Thomas, > > > > However with a DPDK solution it would be possible to re-use the message bus > > > to pass information like device stats, application state, D-state requests > > > etc. to the host and allow for management layer(e.g. OpenStack) to make > > > informed decisions. > > > > I think that management informations should be transmitted in a management > > channel. Such solution should exist in OpenStack. > > Perhaps it does, but this solution is not exclusive to OpenStack and just a potential use case. > > > > > > Also, the scope of adding power management to qemu/KVM would be huge; > > > while the easier path is not always the best and the problem of power > > > management in VMs is both a DPDK problem (given that librte_power only > > > worked on the host) and a general virtualization problem that would be > > > better solved by those with direct knowledge of Qemu/KVM architecture > > > and influence on the direction of the Qemu project. > > > > Being a huge effort is not an argument. > > I agree completely and was implied by what followed the conjunction. > > > Please check with Qemu community, they'll welcome it. > > > > > As it stands, the host backend is simply an example application that can > > > be replaced by a VMM or Orchestration layer, by using Virtio-Serial it has > > > obvious leanings to Qemu, but even this could be easily swapped out for > > > XenBus, IVSHMEM, IP etc. > > > > > > If power management is to be eventually supported by Hypervisors directly > > > then we could also enable to option to switch to that environment, currently > > > the librte_power implementations (VM or Host) can be selected dynamically > > > (environment auto-detection) or explicitly via rte_power_set_env(), adding > > > an arbitrary number of environments is relatively easy. > > > > Yes, you are adding a new layer to workaround hypervisor lacks. And this layer > > will handle native support when it will exist. But if you implement native > > support now, we don't need this extra layer. > > Indeed, but we have a solution implemented now and yes it is a workaround, that is until Hypervisors support such functionality. It is possible that whatever solutions for power management present themselves in the future may require workarounds also, us-vhost is an example of such a workaround introduced to DPDK. > > > > > > I hope this helps to clarify the approach. > > > > Thanks for your explanation. > > Thanks for the feedback. > > > > > -- > > Thomas > > Alan.