Service time is the time required to process a request. In this terminology, it is request-processing latency: the work performed by the system itself, distinct from network and queuing delays. section 1.1
Terminology varies: some definitions make response time the sum of service time and wait time, while this model treats response time as total request latency. Separating the components can be difficult when request processing includes queues. section 1.1
An end-to-end web request
A server’s service time excludes delays while it waits for external services or while the response travels to the client. The client may add further latency by rendering the page, executing JavaScript, or issuing additional HTTP requests. section 1.1
