Useful image properties in glance - missing hw_cpu_policy and hw_cpu_thread_policy

[Matt Riedemann]

- [x] This is a doc addition request.

Added to nova in mitaka:

http://specs.openstack.org/openstack/nova-specs/specs/mitaka/implemented/virt-driver-cpu-thread-pinning.html

There are three possible values defined in the spec (and in nova code here):

https://github.com/openstack/nova/blob/d7a87fad357dc635212ce96609dbc2b5c8a67871/nova/objects/fields.py#L260

-----------------------------------
Release: on 2018-07-27 07:30
SHA: ff77f59bd4376be3bed8f8c62258f9973b7ef1f2
Source: https://git.openstack.org/cgit/openstack/glance/tree/doc/source/admin/useful-image-properties.rst
URL: https://docs.openstack.org/glance/latest/admin/useful-image-properties.html

[Matt Riedemann (mriedem)]

The value descriptions are also in the nova flavor extra specs docs:

https://docs.openstack.org/nova/latest/user/flavors.html

Valid CPU-THREAD-POLICY values are:

    prefer: (default) The host may or may not have an SMT architecture. Where an SMT architecture is present, thread siblings are preferred.
    isolate: The host must not have an SMT architecture or must emulate a non-SMT architecture. If the host does not have an SMT architecture, each vCPU is placed on a different core as expected. If the host does have an SMT architecture - that is, one or more cores have thread siblings - then each vCPU is placed on a different physical core. No vCPUs from other guests are placed on the same core. All but one thread sibling on each utilized core is therefore guaranteed to be unusable.
    require: The host must have an SMT architecture. Each vCPU is allocated on thread siblings. If the host does not have an SMT architecture, then it is not used. If the host has an SMT architecture, but not enough cores with free thread siblings are available, then scheduling fails.

[Matt Riedemann (mriedem)]

NOTE: The hw_cpu_thread_policy property is only valid if hw_cpu_policy is set to dedicated. And "hw_cpu_policy" is also not documented in image properties, but is in flavor extra specs:

Valid CPU-POLICY values are:

    shared: (default) The guest vCPUs will be allowed to freely float across host pCPUs, albeit potentially constrained by NUMA policy.
    dedicated: The guest vCPUs will be strictly pinned to a set of host pCPUs. In the absence of an explicit vCPU topology request, the drivers typically expose all vCPUs as sockets with one core and one thread. When strict CPU pinning is in effect the guest CPU topology will be setup to match the topology of the CPUs to which it is pinned. This option implies an overcommit ratio of 1.0. For example, if a two vCPU guest is pinned to a single host core with two threads, then the guest will get a topology of one socket, one core, two threads.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/587199

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/587199
Committed: https://git.openstack.org/cgit/openstack/glance/commit/?id=d2a5c52680d11c3db34ce5264e312bc96854ff78
Submitter: Zuul
Branch: master

commit d2a5c52680d11c3db34ce5264e312bc96854ff78
Author: Matt Riedemann <email address hidden>
Date: Mon Jul 30 15:26:07 2018 -0400

    Document hw_cpu_policy and hw_cpu_thread_policy image properties

    These were found in the nova flavor extra specs docs [1] but not
    the image properties docs, so they are added here.

    [1] https://docs.openstack.org/nova/latest/user/flavors.html

    Change-Id: I2225821f859d43b1458174b8b7baa05c50cd0cd7
    Closes-Bug: #1784462

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/glance 17.0.0.0rc1 release candidate.