An interrupt is generated based on an event. Further, a thread is selected for monitoring. In addition, an interrupt handler captures information for the monitored thread. An affinity of the monitored thread is set such that the monitored thread runs only on a current processor without being able to migrate to a different processor. A sampler thread that runs on the current processor retrieves a call stack associated with a monitored thread after the affinity of the monitored thread has been set to the current processor.