A service provider network offers various services to users. Some of the services may be stateless services. Data flow tokens may be generated and embedded in packets that are provided to the various services. A data flow token uniquely identifies the data flow for a set of services that are invoked by, for example, an application programming interface (API) call to the service provider network. The various services that are invoked as part of a common data flow write diagnostics data to a diagnostics log service. The diagnostics data may include the data flow token as well as a time stamp when the service was invoked and a time stamp when the service completes. The time stamps can be used to determine the period of time that the service took to execute. Analysis of the execution times can assist in, for example, auto-scaling the services for better performance.