Transactional memory

About: Transactional memory is a research topic. Over the lifetime, 2365 publications have been published within this topic receiving 60818 citations.

Method, device and system for transactional memory in out-of-order processors

Abstract: Methods and apparatus to provide transactional memory execution in out-of-order processors are described. In one embodiment, a stored value corresponds to the number of transactional memory access requests that are uncommitted. The stored value may be used to provide nested recovery in case of an error, fault, etc. in accordance with a described embodiment.

Adaptive Hybrid Transaction Processing with Hardware Transaction Memory

Abstract: Many performance-sensitive software systems gain benefit from the availability of advanced hardware features, and many research works have been transited to engineering reality. For instance, restricted hardware transaction memory (HTM), a hardware feature providing hardware atomicity and isolation guarantees for transactional execution, has gained much attention in the community of database system and becomes a new kind of approach for concurrency control of transaction processing. Previous works show that hardware transactional memory is a very promising mechanism when processing typical OLTP workloads and scales well on multi-core machines. However, the high transaction abort rate caused by capacity overflow is also the major trouble when applying hardware transactional memory in transaction execution under high-contention workloads. Many methods, such as falling back to lock-based approaches, have been proposed to improve the performance when applying hardware transactional memory to transaction execution. In this paper, we analyze the penalty of abort and fall back when hardware transactional memory fails to process transactions. Based on these analyses, we exploit the strengths of hardware transactional memory with an adaptive hybrid mechanism to improve both the throughput and latency of transaction processing on the multicore systems. Our experiment on TPC-C shows that our adaptive design can remarkably improve the throughput and latency of in-memory transaction processing.

of Unified Signatures for Transactional Memory Systems

Abstract: Hardwar e signatures have been used for detecting conflicts in Transactional Memory (TM) systems. Even with its area-efficiency, a signature can degrade TM performance by falsely detecting conflicts. Hence, increasing the accuracy of signatures with limited hardware resources is a crucial issue. We propose a simple and efficient signature design, unified signature. Instead of using separate read- and write-signatures , we implement a single signature to track all read- and write­ accesses, effectively enlarging the signature size without additional overhead. Our results show that a TM system with a 4K-bit blind unified signature achieves average speedups of 8% over baseline TM systems with 38% less power and 17% less area.

Identifying read-set information based on an encoding of replaceable-information values

Abstract: An apparatus comprises processing circuitry, transactional memory support circuitry and a cache. The processing circuitry processes threads of data processing, and the transactional memory support circuitry supports execution of a transaction within a thread, including tracking a read set of addresses, comprising addresses accessed by read instructions within the transaction. A transaction comprises instructions for which the processing circuitry is configured to prevent commitment of the results of speculatively executed instruction until the transaction has completed. The cache has a plurality of entries, each associated with an address and specifying a replaceable-information value for that address that comprises information for which, outside of the transaction, processing would be functionally correct even if the information was incorrect. While the transaction is pending, the transactional memory support circuitry identifies, based on an encoding of the replaceable-information values, read-set information identifying addresses in the read set tracked for the transaction.