openstack/nova
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docs: Clarify value for 'hw:cpu_realtime' extra spec

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Per review feedback.

Change-Id: I663ccd3ff737fb384e0b39f920c406367aea55e1
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
This commit is contained in:
Stephen Finucane 2021-03-24 12:50:12 +00:00
parent 777c02485f
commit e89125a422
1 changed files with 10 additions and 11 deletions
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21
doc/source/admin/real-time.rst
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@ -74,9 +74,8 @@ Configuring a flavor or image
.. versionchanged:: 22.0.0 (Victoria)
Previously, it was necessary to specify
:nova:extra-spec:`hw:cpu_realtime_mask` when
:nova:extra-spec:`hw:cpu_realtime` was set to ``true``.
Starting in Victoria, it is possible
:nova:extra-spec:`hw:cpu_realtime_mask` when realtime mode was enabled via
:nova:extra-spec:`hw:cpu_realtime`. Starting in Victoria, it is possible
to omit this when an emulator thread policy is configured using the
:nova:extra-spec:`hw:emulator_threads_policy` extra spec, thus allowing all
guest cores to be be allocated as real-time cores.
@ -92,14 +91,14 @@ and merely requires a combination of flavor extra specs and image metadata
properties, along with a suitable real-time guest OS.
Enable real-time by setting the :nova:extra-spec:`hw:cpu_realtime` flavor extra
spec to ``true``. When this is configured, it is necessary to specify where
guest overhead processes should be scheduled to. This can be accomplished in
one of three ways. Firstly, the :nova:extra-spec:`hw:cpu_realtime_mask` extra
spec or equivalent image metadata property can be used to indicate which guest
cores should be scheduled as real-time cores, leaving the remainder to be
scheduled as non-real-time cores and to handle overhead processes. For example,
to allocate the first two cores of an 8 core instance as the non-real-time
cores:
spec to ``yes`` or a truthy value. When this is configured, it is necessary to
specify where guest overhead processes should be scheduled to. This can be
accomplished in one of three ways. Firstly, the
:nova:extra-spec:`hw:cpu_realtime_mask` extra spec or equivalent image metadata
property can be used to indicate which guest cores should be scheduled as
real-time cores, leaving the remainder to be scheduled as non-real-time cores
and to handle overhead processes. For example, to allocate the first two cores
of an 8 core instance as the non-real-time cores:
.. code-block:: console