System and method for executing a transaction using parallel co-transactions

Abstract

The transactional memory system described herein may implement parallel co-transactions that access a shared memory such that at most one of the co-transactions in a set will succeed and all others will fail (e.g., be aborted). Co-transactions may improve the performance of programs that use transactional memory by attempting to perform the same high-level operation using multiple algorithmic approaches, transactional memory implementations and/or speculation options in parallel, and allowing only the first to complete to commit its results. If none of the co-transactions succeeds, one or more may be retried, possibly using a different approach and/or transactional memory implementation. The at-most-one property may be managed through the use of a shared 'done' flag. Conflicts between co-transactions in a set and accesses made by transactions or activities outside the set may be managed using lazy write ownership acquisition and/or a priority-based approach. Each co-transaction may execute on a different processor resource.