Static phases

An application typically goes through several phases in its execution. To track the performance of the application based on phases, TAU provides static and dynamic phase profiling. A profile based on phases highlights the context in which a routine is called. An application has a default phase within which other routines and phases are invoked. A phase based profile shows the time spent in a routine when it was in a given phase. So, if a set of instrumented routines are called directly or indirectly by a phase, we'd see the time spent in each of those routines under the given phase. Since phases may be nested, a routine may belong to only one phase. When more than one phase is active for a given routine, the closest ancestor phase of a routine along its callstack is its phase for that invocation. The performance data generated can answer questions such as: what is the total time spent in MPI_Send() when it was invoked in all invocations of the IO (IO => MPI_Send()) phase?