Flat combining and the synchronization-parallelism tradeoff

Traditional data structure designs, whether lock-based or lock-free, provide parallelism via fine grained synchronization among threads. We introduce a new synchronization paradigm based on coarse locking, which we call flat combining. The cost of synchronization in flat combining is so low, that having a single thread holding a lock perform the combined access requests of all others, delivers, up to a certain non-negligible concurrency level, better performance than the most effective parallel finely synchronized implementations. We use flat-combining to devise, among other structures, new linearizable stack, queue, and priority queue algorithms that greatly outperform all prior algorithms. Categories and Subject Descriptors D.2.8 [Software Engineering]: Algorithms General Terms Algorithms, Performance Keywords Multiprocessors, Concurrent Data-Structures, Synchronization

• Type: Conference
• Year: 2010
• Where: SPAA
• Authors: Danny Hendler, Itai Incze, Nir Shavit, Moran Tzafrir
• Keywords: Distributed And Parallel Computing, SPAA 2010, Synchronization, fine Grained Synchronization, flat Combining