Optimization for safe elimination of weak atomicity overhead

摘要

A method and apparatus for optimizing weak atomicity overhead is herein described. A state table is maintained either during static or dynamic compilation of code to track data non-transactionally accessed. Within execution of a transaction, such as at transactional memory accesses or within a commit function, it is determined if data associated with memory access within the transaction is to be conflictingly accessed outside the transaction from the state table. If the data is not accessed outside the transaction, then the transaction potentially commits without weak atomicity safety mechanisms, such as privatization. Furthermore, even if data is accessed outside the transaction, optimized safety mechanisms may be performed to ensure isolation between the potentially conflicting accesses, while eliding the mechanisms for data not accessed outside the transaction.

主权项

1. A non-transitory machine readable medium including program code which, when executed by a machine, causes the machine to:
determine, before execution of a transactional access to a particular data element, determine whether a potential conflict exists between the transitional access of the particular data element and a non-transitional access of the particular data element; to be accessed within a transaction is to be potentially conflictingly accessed outside the transaction based on an entry of a state table for the data, wherein the entry of the state of the table is to hold a reference to the data for a non-transactional access state and includes a data element reference field and a state field associated with the data element; and if a potential conflict exists, perform a safety mechanism for the transactional access, wherein the safety mechanism is selected from a group consisting of a privatization safety mechanism, a publication safety mechanism, and a granular safety mechanism; and if a potential conflict does not exists, elide the safety mechanism for the transactional access in response to determining the particular data element is to be potentially conflictingly accessed outside the transaction.