In one embodiment, a method receives execution timelines that include nodes representing function calls and execution times from executing a first version of an application and a second version of the application. The method selects pairs of nodes from a first set of nodes from a first execution timeline and a second set of nodes from a second execution timeline. The method then iterates through the pairs of nodes to determine (1) whether a node in the second execution timeline is not included in the first execution timeline and has an execution time slower than a set difference; or (2) whether a first node in the second execution timeline has an execution time slower than a second node in the first execution timeline by the set difference. A critical graph is generated that defines a path of nodes that lead to a node that has been identified as a performance regression cause.