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From: "Carew, Alan" <alan.carew@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>,
	"De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [dpdk-dev] [PATCH v4 00/10] VM Power Management
Date: Fri, 12 Dec 2014 13:00:50 +0000
Message-ID: <0E29434AEE0C3A4180987AB476A6F6306D2B6443@IRSMSX109.ger.corp.intel.com> (raw)
In-Reply-To: <10291528.MoKaz8pbFD@xps13>

Hi Paolo,

> 2014-12-09 18:35, Paolo Bonzini:
> > >>>> 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.
> > >>>
> > >>> Unfortunately, I have not yet received any feedback:
> > >>> http://lists.nongnu.org/archive/html/qemu-devel/2014-
> 11/msg01103.h
> > >>> tml
> > >>
> > >> Just to add to what Alan said above, this capability does not exist
> > >> in qemu at the moment, and based on there having been no feedback
> > >> on th qemu mailing list so far, I think it's reasonable to assume
> > >> that it will not be implemented in the immediate future. The VM
> > >> Power Management feature has also been designed to allow easy
> > >> migration to a qemu-based solution when this is supported in
> > >> future. Therefore, I'd be in favour of accepting this feature into DPDK
> now.
> > >>
> > >> It's true that the implementation is a work-around, but there have
> > >> been similar cases in DPDK in the past. One recent example that
> > >> comes to mind is userspace vhost. The original implementation could
> > >> also be considered a work-around, but it met the needs of many in
> > >> the community. Now, with support for vhost-user in qemu 2.1, that
> > >> implementation is being improved. I'd see VM Power Management
> > >> following a similar path when this capability is supported in qemu.
> >
> > I wonder if this might be papering over a bug in the host cpufreq
> > driver.  If the guest is not doing much and leaving a lot of idle CPU
> > time, the host should scale down the frequency of that CPU.  In the
> > case of pinned VCPUs this should really "just work".  What is the
> > problem that is being solved?
> >
> > Paolo
> 
> Alan, Pablo, please could you explain your logic with VM power
> management?
> 
> --
> Thomas

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.

Thanks,
Alan.

  reply	other threads:[~2014-12-12 13:00 UTC|newest]

Thread overview: 97+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-22 18:34 [dpdk-dev] [PATCH " Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 01/10] Channel Manager and Monitor for VM Power Management(Host) Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 02/10] VM Power Management CLI(Host) Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 03/10] CPU Frequency Power Management(Host) Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 04/10] " Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 05/10] VM communication channels for VM Power Management(Guest) Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 06/10] Alternate implementation of librte_power " Alan Carew
2014-09-22 19:17   ` Neil Horman
2014-09-23  7:48     ` Carew, Alan
2014-09-22 18:34 ` [dpdk-dev] [PATCH 07/10] Packet format for VM Power Management(Host and Guest) Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 08/10] Build system integration for VM Power Management(Guest and Host) Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 09/10] VM Power Management Unit Tests(Guest) Alan Carew
2014-09-22 18:34 ` [dpdk-dev] [PATCH 10/10] VM Power Management CLI(Guest) Alan Carew
2014-09-24 17:26 ` [dpdk-dev] [PATCH v2 00/10] VM Power Management Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 01/10] Channel Manager and Monitor for VM Power Management(Host) Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 02/10] VM Power Management CLI(Host) Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 03/10] CPU Frequency Power Management(Host) Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 04/10] VM Power Management application and Makefile Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 05/10] VM Power Management CLI(Guest) Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 06/10] VM communication channels for VM Power Management(Guest) Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 07/10] librte_power common interface for Guest and Host Alan Carew
2014-09-25 10:10     ` Neil Horman
2014-09-25 17:06       ` Carew, Alan
2014-09-25 17:49         ` Neil Horman
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 08/10] Packet format for VM Power Management(Host and Guest) Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 09/10] Build system integration for VM Power Management(Guest and Host) Alan Carew
2014-09-24 17:26   ` [dpdk-dev] [PATCH v2 10/10] VM Power Management Unit Tests Alan Carew
2014-09-25  2:56   ` [dpdk-dev] [PATCH v2 00/10] VM Power Management Liu, Yong
2014-09-29 15:18   ` [dpdk-dev] [PATCH v3 " Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 01/10] Channel Manager and Monitor for VM Power Management(Host) Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 02/10] VM Power Management CLI(Host) Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 03/10] CPU Frequency Power Management(Host) Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 04/10] VM Power Management application and Makefile Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 05/10] VM Power Management CLI(Guest) Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 06/10] VM communication channels for VM Power Management(Guest) Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 07/10] librte_power common interface for Guest and Host Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 08/10] Packet format for VM Power Management(Host and Guest) Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 09/10] Build system integration for VM Power Management(Guest and Host) Alan Carew
2014-09-29 15:18     ` [dpdk-dev] [PATCH v3 10/10] VM Power Management Unit Tests Alan Carew
2014-09-29 17:29     ` [dpdk-dev] [PATCH v3 00/10] VM Power Management Neil Horman
2014-10-12 19:36     ` [dpdk-dev] [PATCH v4 " Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 01/10] Channel Manager and Monitor for VM Power Management(Host) Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 02/10] VM Power Management CLI(Host) Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 03/10] CPU Frequency Power Management(Host) Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 04/10] VM Power Management application and Makefile Alan Carew
2014-10-16 18:28         ` De Lara Guarch, Pablo
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 05/10] VM Power Management CLI(Guest) Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 06/10] VM communication channels for VM Power Management(Guest) Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 07/10] librte_power common interface for Guest and Host Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 08/10] Packet format for VM Power Management(Host and Guest) Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 09/10] Build system integration for VM Power Management(Guest and Host) Alan Carew
2014-10-12 19:36       ` [dpdk-dev] [PATCH v4 10/10] VM Power Management Unit Tests Alan Carew
2014-10-13  6:17       ` [dpdk-dev] [PATCH v4 00/10] VM Power Management Liu, Yong
2014-10-13 20:26       ` Thomas Monjalon
2014-10-14 12:37         ` Carew, Alan
2014-10-14 15:03           ` Thomas Monjalon
2014-10-16 15:21             ` Carew, Alan
2014-10-28 15:21               ` Thomas Monjalon
2014-11-10  9:05                 ` Carew, Alan
2014-11-10 17:54                   ` O'driscoll, Tim
2014-11-21 23:51                     ` Zhu, Heqing
2014-11-22 17:17                     ` Vincent JARDIN
2014-12-09 17:35                       ` Paolo Bonzini
2014-12-11 23:18                         ` Thomas Monjalon
2014-12-12 13:00                           ` Carew, Alan [this message]
2014-12-12 14:50                             ` Paolo Bonzini
2014-12-12 16:10                               ` Thomas Monjalon
2014-12-12 16:13                                 ` Paolo Bonzini
2014-11-21 17:42       ` [dpdk-dev] [PATCH v5 00/10] Virtual Machine " Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 01/10] Channel Manager and Monitor for VM Power Management(Host) Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 02/10] VM Power Management CLI(Host) Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 03/10] CPU Frequency Power Management(Host) Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 04/10] VM Power Management application and Makefile Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 05/10] VM Power Management CLI(Guest) Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 06/10] VM communication channels for VM Power Management(Guest) Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 07/10] librte_power common interface for Guest and Host Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 08/10] Packet format for VM Power Management(Host and Guest) Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 09/10] Build system integration for VM Power Management(Guest and Host) Pablo de Lara
2014-11-21 17:42         ` [dpdk-dev] [PATCH v5 10/10] VM Power Management Unit Tests Pablo de Lara
2014-11-25 16:18         ` [dpdk-dev] [PATCH v6 00/10] Virtual Machine Power Management Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 01/10] Channel Manager and Monitor for VM Power Management(Host) Pablo de Lara
2014-11-29 15:21             ` Neil Horman
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 02/10] VM Power Management CLI(Host) Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 03/10] CPU Frequency Power Management(Host) Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 04/10] VM Power Management application and Makefile Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 05/10] VM Power Management CLI(Guest) Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 06/10] VM communication channels for VM Power Management(Guest) Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 07/10] librte_power common interface for Guest and Host Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 08/10] Packet format for VM Power Management(Host and Guest) Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 09/10] Build system integration for VM Power Management(Guest and Host) Pablo de Lara
2014-11-25 16:18           ` [dpdk-dev] [PATCH v6 10/10] VM Power Management Unit Tests Pablo de Lara
2014-11-26 16:41           ` [dpdk-dev] [PATCH v6 00/10] Virtual Machine Power Management Thomas Monjalon
2014-11-10  9:19     ` [dpdk-dev] [PATCH v2] librte_cmdline: FreeBSD Fix oveflow when size of command result structure is greater than BUFSIZ Alan Carew
2014-12-05 14:16       ` Olivier MATZ
2014-12-05 14:19         ` [dpdk-dev] [PATCH v3] " Olivier Matz
2014-12-05 15:51           ` Bruce Richardson
2014-12-05 15:58             ` Thomas Monjalon

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