Final answer:
The command is used to set a global memory usage threshold in a network device or system, helping in the efficient management of a system's resources.
Step-by-step explanation:
The command config system global set memory-use-threshold-xx is a command line instruction used to set the global memory threshold in a network device or firewall system. This instruction is utilized to define a threshold that can trigger certain actions or alerts when the system's memory usage reaches the specified percentage of available memory. It is part of configuring the system to ensure optimal performance and resource management.