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CPU topology and NUMA topology

asked 2018-07-12 23:29:49 -0500

yafeng gravatar image

updated 2018-07-12 23:30:51 -0500

If NUMA topology is set, CPU topology is still needed?

For example, I want to VM to run on one of the host NUMA nodes with four dedicated CPUs, it's enough with following commands?

openstack flavor set FLAVOR-NAME --property hw:numa_nodes=1 --property hw:numa_cpus.0=4 --property hw:cpu_policy=dedicated

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answered 2018-08-13 13:09:15 -0500

volenbovsky gravatar image

No, you can use hw:numa_nodes=1 without hw:numa_cpus But I suggest you to drop both --property hw:numa_nodes=1 --property hw:numa_cpus.0=4. This undermines the cloud concept - you are introducing too much control on allocation.

hw:cpu_policy=dedicated should be enough. -Actually by default as I remember it will never allow you to have the VM split over 2 (or more) NUMA

hw:numa_cpus.0=4 sounds wrong: there you specify CPU IDs, not quantity of CPUs.

Specifying CPU IDs explicitly, as I mentioned below makes it less of a cloud.

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Asked: 2018-07-12 23:29:49 -0500

Seen: 400 times

Last updated: Aug 13 '18