Component-Based Lock Allocation

The allocation of lock objects to critical sections in concurrent programs affects both performance and correctness. Recent work explores automatic lock allocation, aiming primarily to minimize conflicts and maximize parallelism by allocating locks to individual critical section interferences. We investigate component-based lock allocation, which allocates locks to entire groups of interfering critical sections. Our allocator depends on a thread-based side effect analysis, and benefits from precise points-to and may happen in parallel information. Thread-local object information has a small impact, and dynamic locks do not improve significantly on static locks. We experiment with a range of small and large Java benchmarks on 2-way, 4-way, and 8-way machines, and find that a single static lock is sufficient for mtrt, that performance degrades by 10% for hsqldb, that jbb2000 becomes mostly serialized, and that for lusearch, xalan, and jbb2005, component-based lock allocation recovers the performance of the original program.