openstack
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nova
Code Issues Proposed changes

Merge "update default numa allocation strategy"

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Zuul 2022-08-10 21:21:23 +00:00 committed by Gerrit Code Review
parent 99dd3f75cd e76ec7af4d
commit e90fcc1535
2 changed files with 19 additions and 6 deletions
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13
nova/conf/compute.py
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@ -1008,15 +1008,16 @@ Related options:
to be enabled for this to take effect.
"""),
cfg.BoolOpt('packing_host_numa_cells_allocation_strategy',
default=True,
default=False,
help="""
This option controls allocation strategy used to choose NUMA cells on host for
placing VM's NUMA cells (for VMs with defined numa topology). By
default host's NUMA cell with more resources consumed will be chosen first for
placing attempt. So the host cell with some usage will be packed with VM's cell
until it will be completely exhausted, before new free host's cell will be
used. When the packing_host_numa_cells_allocation_strategy variable is set to
``False``, host's NUMA cell with more resources available will be used.
default host's NUMA cell with more resources consumed will be chosen last for
placing attempt. When the packing_host_numa_cells_allocation_strategy variable
is set to ``False``, host's NUMA cell with more resources available will be
used. When set to ``True`` cells with some usage will be packed with VM's cell
until it will be completely exhausted, before a new free host's cell will be
used.
Possible values:

12
releasenotes/notes/default-host-numa-strategy-to-spread-18668c6d80154042.yaml Normal file
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@ -0,0 +1,12 @@
---
upgrade:
- |
During the triage of https://bugs.launchpad.net/nova/+bug/1978372
we compared the performance of nova's numa allocations strategies
as it applied to the large numbers of host and guest numa nodes.
Prior to ``Xena`` nova only supported a linear packing strategy.
In ``Xena`` ``[compute]/packing_host_numa_cells_allocation_strategy``
was introduced maintaining the previous packing behavior by default.
The numa allocation strategy has now been defaulted to spread.
The old behavior can be restored by defining:
``[compute]/packing_host_numa_cells_allocation_strategy=true``