From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id A23B68090 for ; Fri, 12 Dec 2014 15:50:35 +0100 (CET) Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sBCEoW4X007078 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 12 Dec 2014 09:50:32 -0500 Received: from [10.36.112.55] (ovpn-112-55.ams2.redhat.com [10.36.112.55]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id sBCEoREG004156 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 12 Dec 2014 09:50:30 -0500 Message-ID: <548B00B3.8040201@redhat.com> Date: Fri, 12 Dec 2014 15:50:27 +0100 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: "Carew, Alan" , Thomas Monjalon , "De Lara Guarch, Pablo" References: <1412003903-9061-1-git-send-email-alan.carew@intel.com> <5470C514.3080307@6wind.com> <548732C9.2020201@redhat.com> <10291528.MoKaz8pbFD@xps13> <0E29434AEE0C3A4180987AB476A6F6306D2B6443@IRSMSX109.ger.corp.intel.com> In-Reply-To: <0E29434AEE0C3A4180987AB476A6F6306D2B6443@IRSMSX109.ger.corp.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Mailman-Approved-At: Fri, 12 Dec 2014 16:24:36 +0100 Cc: "dev@dpdk.org" , qemu-devel 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: Fri, 12 Dec 2014 14:50:36 -0000 On 12/12/2014 14:00, Carew, Alan wrote: > The problem is deterministic control of host CPU frequency and the DPDK usage > model. > A hands-off power governor will scale based on workload, whether this is a host > application or VM, so no problems or bug there. > > Where this solution fits is where an application wants to control its own > power policy, for example l3fwd_power uses librte_power library to change > frequency via apci_cpufreq based on application heuristics rather than > relying on an inbuilt policy for example ondemand or performance. > > This ability has existed in DPDK for host usage for some time and VM power > management allows this use case to be extended to cater for virtual machines > by re-using the librte_power interface to encapsulate the VM->Host > comms and provide an example means of managing such communications. > > I hope this clears it up a bit. Ok, this looks specific enough that an out-of-band solution within DPDK sounds like the best approach. It seems unnecessary to involve the hypervisor (neither KVM nor QEMU). Paolo