The CPU (MHz) chart displays CPU usage for the host.

This chart is located in the Home view of the Host Performance tab.

Table 1. Data Counters

Chart Label

Description

Usage

The sum, in megahertz, of the actively used CPU of all powered on virtual machines on a host.

The maximum possible value is the frequency of the processors multiplied by the number of processors. For example, if you have a host with four 2GHz CPUs running a virtual machine that is using 4000MHz, the host is using two CPUs completely.

4000 ÷ (4 × 2000) = 0.50

  • Counter: usagemhz

  • Stats Type: Rate

  • Unit: MegaHertz (MHz)

  • Rollup Type: Average (Minimum/Maximum)

  • Collection Level: 1 (4)

Chart Analysis

A short spike in CPU usage indicates that you are making the best use of the host resources. However, if the value is constantly high, the host is probably lacking the CPU required to meet the demand. A high CPU usage value can lead to increased ready time and processor queuing of the virtual machines on the host.

If performance is impacted, consider taking the actions listed below.

Table 2. CPU Performance Enhancement Advice

#

Resolution

1

Verify that VMware Tools is installed on every virtual machine on the host.

2

Set the CPU reservations for all high-priority virtual machines to guarantee that they receive the CPU cycles required.

3

Reduce the number of virtual CPUs on a virtual machine to only the number required to execute the workload. For example, a single-threaded application on a four-way virtual machine only benefits from a single vCPU. But the hypervisor's maintenance of the three idle vCPUs takes CPU cycles that could be used for other work.

4

If the host is not already in a DRS cluster, add it to one. If the host is in a DRS cluster, increase the number of hosts and migrate one or more virtual machines onto the new host.

5

Upgrade the physical CPUs or cores on the host if necessary.

6

Use the newest version of hypervisor software, and enable CPU-saving features such as TCP Segmentation Offload, large memory pages, and jumbo frames.