A Blocking Bound for Nested FIFO Spin Locks

Bounding worst-case blocking delays due to lock contention is a fundamental problem in the analysis of multiprocessor real-time systems. However, virtually all fine-grained (i.e., non-asymptotic) analyses published to date make a simplifying (but impractical) assumption: critical sections must not be nested. This paper overcomes this fundamental limitation and presents the first fine-grained blocking bound for nested non-preemptive FIFO spin locks under partitioned fixed-priority scheduling. To this end, a new analysis method is introduced, based on a graph abstraction that reflects all possible resource conflicts and transitive delays.