[openstack-dev] [nova] [neutron] Adding neutron VIF NUMA locality support

Eric Fried openstack at fried.cc
Thu Sep 7 21:01:58 UTC 2017


	FYI, we're teeing up (anti-)affinity and neutron-nova interaction
topics for the "generic device management" discussions at the PTG.
Please jump on the etherpad [1] and expand/expound in the relevant
spots, which, as of this writing, you can find by searching for
"aggregate", "vf selection policy", and "interplay".



On 09/07/2017 01:07 PM, Mooney, Sean K wrote:
>> -----Original Message-----
>> From: Stephen Finucane [mailto:sfinucan at redhat.com]
>> Sent: Thursday, September 7, 2017 5:42 PM
>> To: OpenStack Development Mailing List (not for usage questions)
>> <openstack-dev at lists.openstack.org>
>> Cc: Jakub Libosvar <jlibosva at redhat.com>; Karthik Sundaravel
>> <ksundara at redhat.com>; Mooney, Sean K <sean.k.mooney at intel.com>
>> Subject: [nova] [neutron] Adding neutron VIF NUMA locality support
>> Hey,
>> NUMA locality matters as much for NICs used e.g for Open vSwitch as for
>> SR-IOV devices. At the moment, nova support NUMA affinity for PCI
>> passthrough devices and SR-IOV devices, but it makes no attempt to do
>> the same for other NICs. In the name of NFV enablement, we should
>> probably close this gap.
> [Mooney, Sean K] I like this idea in general, that said in ovs-dpdk we modified
> ovs to schedule the vhost-user port to be processed on a pmd that is on the same
> Numa node as the vm and reallocate the vhsot user port memory where possible
> To also have the same affinity. 
>> I have some ideas around how this could work, but they're fuzzy enough
>> and involve exchanging os-vif objects between nova and neutron. This is
>> probably the most difficult path as we've been trying to get os-vif
>> objects over the nova-neutron wire for a while now, to no success.
> [Mooney, Sean K] actually we have so poc code you should proably review
> This topic.
> https://blueprints.launchpad.net/os-vif/+spec/vif-port-profile
> https://review.openstack.org/#/c/490829/ 
> https://review.openstack.org/#/c/490819/ 
> https://review.openstack.org/#/c/441590/
> the first patch of the neutron side poc should be up before the ptg.
>> Anyone else keen on such a feature? Given that there are a significant
>> amount of people from nova, neutron, and general NFV backgrounds at the
>> PTG next week, we have a very good opportunity to talk about this
>> (either in the nova- neutron sync, if that's not already full, or in
>> some hallway somewhere).
> [Mooney, Sean K] in terms of basic numa affinity this is not as important
> With ovs-dpdk because we make best effort to fix it in ovs this is less pressing
> Then it used to be. It is still important for other backbends but we need
> Also have a mechanism to control numa affinity policy like 
>  https://review.openstack.org/#/c/361140/ to not break existing deployments.
> I have some taught about modeling network backbends
> in placement and also passing traits requests for neutron that this would dove
> tail with so would love to talk to anyone who is interested in this.
> By modeling ovs and other network backend in placement and combining that
> With traits and the nova-neutron negotiation protocol we support several
> Advance usescase.
> By the way  ovs-dpdk allow you to specify vhost-port rx/tx queue mapping 
> to pmd which could give a nice performance boost if done correctly. It
> might be worth extending os-vif to do that in the future though this could
> equally be handeled by the neutron ovs l2 agent.
>> At this point in the day, this is probably very much a Rocky feature,
>> but we could definitely put in whatever groundwork is necessary this
>> cycle to make the work in Rocky as easy possible.
> [Mooney, Sean K] I'm hoping we can get the nova neutron negotiation done in queens.
>> Cheers,
>> Stephen
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