** Changed in: nova Status: Fix Committed => Fix Released ** Changed in: nova Milestone: None => liberty-2
-- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1471187 Title: CPU topology does not honour cpu_max_threads when NUMA topology is used Status in OpenStack Compute (nova): Fix Released Bug description: Consider a flavour with 4 vcpus, and image property hw:cpu_threads==2. Now the NUMA topology may prefer a thread count of 4, but best of the thread preference set, the guest will end up with 2 sockets, 1 core and 2 threads. Now consider a flavour with 4 vcpus, and image property hw:cpu_max_threads==2. Now the NUMA topology may prefer a thread count of 4, but best of the thread limit is set, so the guest should again end up with 2 sockets, 1 core and 2 threads. The current code in nova.virt.hardware._get_possible_cpu_topologies() is not honouring the cpu_max_threads setting in this scenario though, so the guest ends up with 1 socket, 1 core and 4 threads. This violates the cpu_max_threads setting. Meanwhile if the vCPU count is 6 and the NUMA topology prefers a thread count of 4, then the code is actually incapable of coming up with a valid topology because it only considers topologies with an exact thread count of 4 and 4 does not divide into 6. nova.exception.ImageVCPULimitsRangeImpossible: Requested vCPU limits 6:6:6 are impossible to satisfy for vcpus count 6 which is clearly a bogus error as you can easily satisfy that with 6:1:1, 1:6:1, 1:1:6, 2:1:3, 2:3:1, 3:2:1, 3:1:2, 1:2:3, 1:3:2, so it should have picked 2:1:3, as that has thread count closest matching the NUMA topology and the maximum socket count. To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1471187/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp