openstack/nova
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Merge "Docs: correct cpu_thread_policy explanation"

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Zuul
2021-01-20 17:55:32 +00:00
committed by Gerrit Code Review
parent 6517c56429 3cb1215f19
commit b9c48afd15
1 changed files with 7 additions and 10 deletions
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doc/source/user/flavors.rst
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@@ -475,16 +475,13 @@ CPU pinning policy
- ``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.
non-SMT architecture. Hosts that support SMT (by reporting the
``HW_CPU_HYPERTHREADING`` trait) are excluded.
- ``require``: The host must have an SMT architecture and must report the
``HW_CPU_HYPERTHREADING`` trait. 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.
.. note::