Distributed Latency Profiling through Critical Path Tracing

The collection of ProducerModules creates a graph of subcomponents that are executed by the framework to process the request. For this example, the framework knows which of A2, B1, and B2 was the last to block execution to produce A1's output. Since the framework is aware of the subcomponent dependencies, it can record the critical path. For Google Search, subcomponent-level traces are collected from several software frameworks in multiple programming languages. Framework-level implementation is essential for scalability, since it allows relatively small teams of developers to provide detailed critical path traces for code written by thousands of other people.