Database Reference
In-Depth Information
enabled. If a virtual machine was created that had six vCPUs, this virtual machine
would be assigned to run on one of the four available NUMA nodes. This designation is
called the virtual machine's home NUMA node. Now, a 12 vCPU virtual machine is
created. As part of determining placement, hyper-threading is ignored, so that means this
virtual machine will span two and only two NUMA nodes in our physical server. The
way this works is the maximum number of physical cores in a socket will become the
minimum number of vCPUs assigned for that virtual machine. For the 12-vCPU virtual
machine running on a four-socket, six-core box with hyper-threading enabled, the
NUMA Scheduler will assign a home NUMA node (node 1, 2, 3, or 4) and then manage
six of the 12 vCPUs on this NUMA node. The remaining six will be assigned another
home node on another NUMA node.
Figure 5.7
provides a visual example of this.
Notice how NUMA node 3 has been designated as home node 1, and six vCPUs are
assigned to this NUMA node. Then, NUMA node 1 was selected as home node 2 to run
the remaining six vCPUs.
Figure 5.7
Placement of a 12-vCPU virtual machine by NUMA Scheduler.
You will notice the NUMA Scheduler did not use more NUMA nodes than necessary to
