Application Performance Monitoring
应用性能监控 是指监控、管理软件的性能和可用性，及时发现、判断复杂的应用性能问题，保证 服务级别协议。
Wikipedia
Application performance management (APM) is the monitoring and management of the performance and availability of software applications. APM strives to detect and diagnose complex application performance problems to maintain an expected level of service.[1]