1. A method, comprising: receiving, by a processor-based machine, events that occur as a result of execution of an application; and using the received events to generate, by the processor-based machine, transactions for evaluating the performance of the application when executed, wherein the transactions are generated in accordance with a set of transaction definitions, wherein each transaction definition in the set specifies actions which correspond to a start point and an end point of a transaction associated with execution of the application.