A computer-implemented method, computer program product and computer readable storage medium directed to decentralized load distribution in an event-driven system. Included are receiving a data flow to be processed by a plurality of tasks at a plurality of nodes in the event-driven system having stateful and stateless event processing components, wherein the plurality of tasks are selected from the group consisting of hierarchical tasks (a task that is dependent on the output of another task), nonhierarchical tasks (a task that is not dependent on the output of another task) and mixtures thereof. Tasks are considered for migration to distribute the system load of processing tasks. The target node, to which the at least one target task is migrated, is chosen wherein the target node meets predetermined criteria in terms of load distribution quality. The computer-implemented method, computer program product and computer readable storage medium of the present invention may also include migrating tasks to target nodes to reduce cooling costs and selecting at least one node to go into quiescent mode.