US Patent 8204986 Multi-hierarchy latency measurement in data centers

A method for monitoring performance of a data center that includes: (a) a performance monitor analyzing packets that flow between a client and a web or application server; (b) assigning packets to contexts where a context is a request-reply entity; (c) determining one or more of application, network, and back-end latency measures wherein: (i) the application latency measure is a time it takes for an application to respond to a request, (ii) the network latency measure is a time that it takes for packets to go through a network between the client and the web or application server, and (iii) the back-end latency is a time required for a back-end system to execute a request and respond to the application server.