Trading End-to-End Latency for Composability

The periodic resource model for hierarchical, compositional scheduling abstracts task groups by resource requirements. We study this model in the presence of dataflow constraints between the tasks within a group (intragroup dependencies), and between tasks in different groups (intergroup dependencies). We consider two natural semantics for dataflow constraints, namely, RTW (Real-Time Workshop) semantics and LET (logical execution time) semantics. We show that while RTW semantics offers better endto-end latency on the task group level, LET semantics alhter resource bounds in the abstraction hierarchy and therefore provides better composability properties. This result holds both for intragroup and intergroup dependencies, as well as for shared and for distributed resources.

• Type: Conference
• Year: 2005
• Where: RTSS
• Authors: Slobodan Matic, Thomas A. Henzinger
• Keywords: Applied Computing, Dataflow Constraints, Intergroup Dependencies, RTSS 2005, Semantics