The resxtop utility is a vSphere CLI command.

Before you can use any vSphere CLI commands, you must either download and install a vSphere CLI package or deploy the vSphere Management Assistant (vMA) to your ESXi host or vCenter Server system.

After it is set up, start resxtop from the command line. For remote connections, you can connect to a host either directly or through vCenter Server.

The command-line options listed in the following table are the same as for esxtop (except for the R option) with additional connection options.
Note: resxtop does not use all the options shared by other vSphere  CLI commands.
Table 1. resxtop Command-Line Options
Option Description
[server] Name of the remote host to connect to (required). If connecting directly to the ESXi host, use the name of that host. If your connection to the ESXi host is indirect (that is, through vCenter Server), use the name of the vCenter Server system for this option.
[vihost] If you connect indirectly (through vCenter Server), this option should contain the name of the ESXi host you connect to. If you connect directly to the host, this option is not used. Note that the host name needs to be the same as what appears in the vSphere Web Client.
[portnumber] Port number to connect to on the remote server. The default port is 443, and unless this is changed on the server, this option is not needed.
[username] User name to be authenticated when connecting to the remote host. The remote server prompts you for a password.

You can also use resxtop on a local ESXi host by omitting the server option on the command line. The command defaults to localhost.