Flexible Decoupled Transactional Memory Support

A high-concurrency transactional memory (TM) implementation needs to track concurrent accesses, buffer speculative updates, and manage conflicts. We present a system, FlexTM (FLEXible Transactional Memory), that coordinates four decoupled hardware mechanisms: read and write signatures, which summarize per-thread access sets; per-thread conflict summary tables (CSTs), which identify the threads with which conflicts have occurred; Programmable Data Isolation, which maintains speculative updates in the local cache and employs a thread-private buffer (in virtual memory) in the rare event of overflow; and Alert-On-Update, which selectively notifies threads about coherence events. All mechanisms are softwareaccessible, to enable virtualization and to support transactions of arbitrary length. FlexTM allows software to determine when to manage conflicts (either eagerly or lazily), and to employ a variety of conflict management and commit protocols. We describe an STM-inspired protocol ...

• Type: Conference
• Year: 2008
• Where: ISCA
• Authors: Arrvindh Shriraman, Sandhya Dwarkadas, Michael L. Scott
• Keywords: Hardware, ISCA 2008, Manage Conflicts, Speculative Updates, Transactional Memory