Public bug reported: In bug/1744965(https://bugs.launchpad.net/nova/+bug/1744965), it is reported that the way emulator_threads_policy allocates the extra cpu resource for emulator is not optimal.
This report reports the bug also stays when `cpu_thread_policy=isolate`. The instance I use for testing is a 3-vcpu VM with `cpu_thread_policy=isolate`; before enable this emulator_threads_policy, I reserve 6 cpu (actually 6 threads since we enable hyper threading) in nova config, vcpu_pin_set=8,10,12,32,34,36 Now when we enable emulator_threads_policy, in stead of adding one more thread to this vcpu pin list in the nova config, I end up adding two more sibling threads (on the same core) vcpu_pin_set=8,10,12,16,32,34,36,40 So I ended up using 2 more threads, but only one of them is used for emulator and the other thread is wasted. ** Affects: nova Importance: Undecided Status: New -- 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/1746393 Title: 'cpu_thread_policy' impacts on emulator threads Status in OpenStack Compute (nova): New Bug description: In bug/1744965(https://bugs.launchpad.net/nova/+bug/1744965), it is reported that the way emulator_threads_policy allocates the extra cpu resource for emulator is not optimal. This report reports the bug also stays when `cpu_thread_policy=isolate`. The instance I use for testing is a 3-vcpu VM with `cpu_thread_policy=isolate`; before enable this emulator_threads_policy, I reserve 6 cpu (actually 6 threads since we enable hyper threading) in nova config, vcpu_pin_set=8,10,12,32,34,36 Now when we enable emulator_threads_policy, in stead of adding one more thread to this vcpu pin list in the nova config, I end up adding two more sibling threads (on the same core) vcpu_pin_set=8,10,12,16,32,34,36,40 So I ended up using 2 more threads, but only one of them is used for emulator and the other thread is wasted. To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1746393/+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