How it works…

The CPU scheduler uses processor topology information to optimize the placement of vCPUs onto different sockets.

Cores within a single socket typically use a shared last-level cache. The use of a shared last-level cache can improve vCPU performance if the CPU is running memory-intensive workloads.

By default, the CPU scheduler spreads the load across all the sockets in under-committed systems. This improves performance by maximizing the aggregate amount of cache available to the running vCPUs. For such workloads, it can be beneficial to schedule all the vCPUs on the same socket, with a shared last-level cache, even when the ESXi host is under committed. In such scenarios, you can override the default behavior of the spreading vCPUs across packages by including the following configuration option in the VM's VMX configuration file: sched.cpu.vsmpConsolidate=TRUE. However, it is usually better to stick with the default behavior.