The –perfmode option indicates whether or not the performance mode has been enabled, dedicating resources to binaries within the Server app:

serverinfo --perfmode

If the performance mode has not been enabled then the output will be as such:

Server performance mode is NOT enabled.
To enable performance mode, you can also use serverinfo. This is the only task that the command does that can make any changes to the system and as such is the only time you need to elevate privileges:

sudo serverinfo —setperfmode 1

Or set the boolean value back to 0 to disable.

sudo serverinfo —setperfmode 0