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[109.190.92.136]) by mx.google.com with ESMTPSA id ji10sm15752972wid.7.2014.10.28.08.21.19 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Oct 2014 08:21:20 -0700 (PDT) From: Thomas Monjalon To: "Carew, Alan" Date: Tue, 28 Oct 2014 16:21:02 +0100 Message-ID: <1804867.TWdiCQc2JQ@xps13> Organization: 6WIND User-Agent: KMail/4.14.2 (Linux/3.17.1-1-ARCH; KDE/4.14.2; x86_64; ; ) In-Reply-To: <0E29434AEE0C3A4180987AB476A6F6306D2811AD@IRSMSX109.ger.corp.intel.com> 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-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [PATCH v4 00/10] VM Power Management X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Oct 2014 15:12:33 -0000 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.