Adaptive Processing for Data Sharing with Lock Omission and Lock Selection

Abstract

In a Hardware Lock Elision (HLE) Environment, predictively determining whether a HLE transaction should actually acquire a lock and execute non-transactionally, is provided. Included is, based on encountering an HLE lock-acquire instruction, determining, based on an HLE predictor, whether to elide the lock and proceed as an HLE transaction or to acquire the lock and proceed as a non-transaction; based on the HLE predictor predicting to elide, setting the address of the lock as a read-set of the transaction, and suppressing any write by the lock- acquire instruction to the lock and proceeding in HLE transactional execution mode until an xrelease instruction is encountered wherein the xrelease instruction releases the lock or the HLE transaction encounters a transactional conflict; and based on the HLE predictor predicting not- to-elide, treating the HLE lock-acquire instruction as a non-HLE lock-acquire instruction, and proceeding in non-transactional mode.

Description

technical field [0001] The present disclosure relates generally to transactional memory systems, and more particularly to methods, computer programs, and computer systems for adaptively sharing data by utilizing lock omission and selection of locks. Background technique [0002] The number of central processing unit (CPU) cores on a chip and the number of CPU cores connected to shared memory continues to grow significantly to support increasing workload capacity requirements. The ever-increasing number of CPUs cooperating to handle the same workload places a significant burden on software scalability; for example, shared queues or data structures protected by traditional semaphores become hot spots and result in sub-linear n-way scaling curves. Traditionally, this has been dealt with by implementing finer-grained locking in software. Implementing finer-grained locking to improve software scalability can be very complex and error-prone, and at today's CPU frequencies, the la...

AI Technical Summary

Problems solved by technology

Transactions execute optimistically without acquiring locks, however, transactional execution may need to be aborted and retried if an operation of an executing transaction on a memory location conflicts with another operation on the same memory location

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