1. A computer program product comprising a computer readable storage medium having a computer readable program, wherein the computer readable program when executed on a computer causes the computer to: set a processor affinity of a next dispatched monitored thread to a first value, wherein the next dispatched monitored thread executes on a current processor without being able to migrate to a different processor while a next dispatched monitored thread call stack is being retrieved; retrieve the next dispatched monitored thread call stack; and restore the processor affinity of the next dispatched monitored thread to a second value after the next dispatched monitored thread call stack has been retrieved, wherein the next dispatched monitored thread migrates to a different processor to continue execution; and record the next dispatched monitored thread call stack for a subsequently dispatched monitored thread.