Abstract: One embodiment of the present invention provides a system that facilitates performing operations on a lock-free double-ended queue (deque). This deque is implemented as a doubly-linked list of nodes formed into a ring, so that node pointers in one direction form an inner ring, and node pointers in the other direction form an outer ring. The deque has an inner hat, which points to a node next to the last occupied node along the inner ring, and an outer hat, which points to a node next to the last occupied node along the outer ring. The system uses a double compare-and-swap (DCAS) operation while performing pop and push operations onto either end of the deque, as well as growing and shrinking operations to change the number of nodes that are in the ring used by the deque.

Abstract: A multiprocessor, multi-program, stop-the-world garbage collection program is described. The system initially over partitions the root sources, and then iteratively employs static and dynamic work balancing. Garbage collection threads compete dynamically for the initial partitions. Work stealing double-ended queues, where contention is reduced, are described to provide dynamic load balancing among the threads. Contention is resolved by using atomic instructions. The heap is broken into a young and an old generation where parallel semi-space copying is used to collect the young generation and parallel mark-compacting the old generation. Speed and efficiency of collection is enhanced by use of card tables and linking objects, and overflow conditions are efficiently handled by linking using class pointers. A garbage collection termination employs a global status word.