Reviewed: https://review.openstack.org/285321 Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=0b2e34f92507fd490faaec3285049b28446dc94c Submitter: Jenkins Branch: master
commit 0b2e34f92507fd490faaec3285049b28446dc94c Author: Stephen Finucane <[email protected]> Date: Fri Feb 26 13:07:56 2016 +0000 virt/hardware: Fix 'isolate' case on non-SMT hosts The 'isolate' policy is supposed to function on both hosts with an SMT architecture (e.g. HyperThreading) and those without. The former is true, but the latter is broken due to a an underlying implementation detail in how vCPUs are "packed" onto pCPUs. The '_pack_instance_onto_cores' function expects to work with a list of sibling sets. Since non-SMT hosts don't have siblings, the function is being given a list of all cores as one big sibling set. However, this conflicts with the idea that, in the 'isolate' case, only one sibling from each sibling set should be used. Using one sibling from the one available sibling set means it is not possible to schedule instances with more than one vCPU. Resolve this mismatch by instead providing the function with a list of multiple sibling sets, each containing a single core. This also resolves another bug. When booting instances on a non-HT host, the resulting NUMA topology should not define threads. By correctly considering the cores on these systems as non-siblings, the resulting instance topology will contain multiple cores with only a single thread in each. Change-Id: I2153f25fdb6382ada8e62fddf4215d9a0e3a6aa7 Closes-bug: #1550317 Closes-bug: #1417723 ** Changed in: nova Status: In Progress => Fix Released -- 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/1550317 Title: 'hw:cpu_thread_policy=isolate' does not schedule on non-HT hosts Status in OpenStack Compute (nova): Fix Released Bug description: The 'isolate' policy is supposed to function on both hosts with HyperThreading (HT) and those without. The former works, but the latter does not. This appears to be a regression. Results below. --- # Platform Testing was conducted on two single-node, Fedora 23-based (4.3.5-300.fc23.x86_64) OpenStack instances (built with devstack). The systems are a dual-socket, ten core, systems with HT enabled on one and disabled on the other (2 sockets * 10 cores * 1/2 threads = 20/40 "pCPUs". 0-9/0-9,20-29 = node0, 10-19/10-19,30-39 = node1). Commit `8bafc9` of Nova was used. # Steps ## Create flavors $ openstack flavor create pinned.isolate \ --id 103 --ram 2048 --disk 0 --vcpus 4 $ openstack flavor set pinned.isolate \ --property "hw:cpu_policy=dedicated" \ --property "hw:cpu_thread_policy=isolate" ## Validate a HT-enabled node This should match the expectations of the spec and provide a single thread to guests while avoiding other guests scheduling on the other host sibling threads. Therefore, the guest should see four sockets, one core per socket, and one thread per core. $ openstack server create --flavor=pinned.isolate \ --image=cirros-0.3.4-x86_64-uec --wait test1 $ sudo virsh list Id Name State ---------------------------------------------------- 3 instance-00000003 running $ sudo virsh dumpxml 3 <domain type='kvm' id='3'> <name>instance-00000003</name> ... <vcpu placement='static'>4</vcpu> <cputune> <shares>4096</shares> <vcpupin vcpu='0' cpuset='1'/> <vcpupin vcpu='1' cpuset='0'/> <vcpupin vcpu='2' cpuset='25'/> <vcpupin vcpu='3' cpuset='8'/> <emulatorpin cpuset='0-1,8,25'/> </cputune> <numatune> <memory mode='strict' nodeset='0'/> <memnode cellid='0' mode='strict' nodeset='0'/> </numatune> ... <cpu> <topology sockets='4' cores='1' threads='1'/> <numa> <cell id='0' cpus='0-3' memory='2097152' unit='KiB'/> </numa> </cpu> ... </domain> $ openstack server delete test1 No problems here. ## Validate a HT-disabled node This should work exactly the same here as it did on the HT-enabled host, minus the reservation of any thread sibling (there aren't any) $ openstack server create --flavor=pinned.isolate \ --image=cirros-0.3.4-x86_64-uec --wait test1 Error creating server: test1 Error creating server $ openstack server list +--------------------------------------+-------+--------+----------+ | ID | Name | Status | Networks | +--------------------------------------+-------+--------+----------+ | 1f212d45-585e-41df-abd7-6abb12ca86a1 | test1 | ERROR | | +--------------------------------------+-------+--------+----------+ To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1550317/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
