Making the fast case common and the uncommon case simple in unbounded transactional memory

Hardware transactional memory has great potential to simplify the creation of correct and efficient multithreaded programs, allowing programmers to exploit more effectively the soon-to-be-ubiquitous multi-core designs. Several recent proposals have extended the original bounded transactional memory to unbounded transactional memory, a crucial step toward transactions becoming a generalpurpose primitive. Unfortunately, supporting the concurrent execution of an unbounded number of unbounded transactions is challenging, and as a result, many proposed implementations are complex. This paper explores a different approach. First, we introduce the permissions-only cache to extend the bound at which transactions overflow to allow the fast, bounded case to be used as frequently as possible. Second, we propose ONETM to simplify the implementation of unbounded transactional memory by bounding the concurrency of transactions that overflow the cache. These mechanisms work synergistically to pro...

• Type: Conference
• Year: 2007
• Where: ISCA
• Authors: Colin Blundell, Joe Devietti, E. Christopher Lewis, Milo M. K. Martin
• Keywords: Hardware, ISCA 2007, Permissions-only Cache, Transactional Memory, Unbounded Transactional Memory