Hierarchical real-time garbage collection

Memory management is a critical issue for correctness and performance in real-time embedded systems. Recent work on real-time garbage collectors has shown that it is possible to provide guarantees on worst-case pause times and minimum mutator utilization time. This paper presents a new hierarchical real-time garbage collection algorithm for mixed-priority and mixed-criticality environments. With hierarchical garbage collection, real-time programmers can partition the heap into a number of heaplets and for each partition choose to run a separate collector with a schedule that matches the allocation behavior and footprint of the real-time task using it. This approach lowers worst-case response times of real-time applications by 26%, while almost doubling mutator utilization -- all with only minimal changes to the application code.