libvirt not configured with numad support

[Blair Bethwaite]

numad is now packaged and shipped by Ubuntu. But Ubuntu libvirt packages (which is presumably where most end-user/admins/deployers would be interested in numad support) are not configured with numad support...

curl -s https://launchpadlibrarian.net/253913675/buildlog_ubuntu-xenial-amd64.libvirt_1.3.1-1ubuntu10_BUILDING.txt.gz | gunzip | nl | grep numad
  3249 checking for numad... no
  3454 configure: numad: no

[James Page (james-page)]

Hi Blair

Could you add some details as to what is not functional re OpenStack integration with NUMA as well?

After some discussion we think that static numa configuration should work fine; its just the dynamic numad based 'auto' option that will not be functional so it would be good to understand the use-case you have in OpenStack.

[Blair Bethwaite (blair-bethwaite)]

Hi James,

True that static NUMA placement would work (well, it would if this was fixed: https://bugs.launchpad.net/nova/+bug/1517006). But the issue with the static approach is that it requires flavor definitions and imposes stricter scheduling constraints in order to meet the pre-defined flavor NUMA topology and policy.

We're doing science computing and hpc on OpenStack (using libvirt/kvm on ubuntu as hypervisor) and have done a bit of performance testing with strict NUMA policy versus numad. We've done some benchmarking of whole-node VM instances (as would be the case with most hpc workloads) and found that for the most part numad does a near enough job to static pinning (i.e., setting the guest up to mirror the host) that we would prefer to just use numad and get more performance without compromising scheduling flexibility. We'd also do this in our general purpose zones/cells where we have all sorts of mixed research workloads.

Hope that helps explain it?

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Christian Ehrhardt  (paelzer)]

Hi, just came by this bug and dup'ing it to focus all the "enable numad in libvirt" bugs in one place.