Computer systems and methods for call-stacks representation for easier analysis of thread dumps. Execution data for a number of process threads are accessed by a parser in a thread dump wherein execution data includes a number of call-stacks. Process threads have corresponding call-stacks comprising information about active program subroutines of the thread. Threads are grouped in a number of sets that include threads with one or more actions in common. The sets correspond to a same action or subroutine in the call-stacks of the grouped threads. A tree representation of the execution data is generated based on the active actions in the call-stacks. In the tree representation, a first set of grouped threads is a child to a second set of grouped threads when the action corresponding to the first set is invoked by the subroutine corresponding to the second set.