Speculative synchronization for coherence-free embedded NUMA architectures

High-end embedded systems, like their general-purpose counterparts, are turning to many-core cluster-based shared-memory architectures that provide a shared memory abstraction subject to non-uniform memory access (NUMA) costs. In order to keep the cores and memory hierarchy simple, many-core embedde...

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Bibliographic Details
Published in2014 International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS XIV) pp. 99 - 106
Main Authors Papagiannopoulou, Dimitra, Moreshet, Tali, Marongiu, Andrea, Benini, Luca, Herlihy, Maurice, Iris Bahar, R.
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.07.2014
Subjects
Computational modeling
Computer architecture
Embedded systems
Hardware
Program processors
Protocols
Synchronization
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DOI10.1109/SAMOS.2014.6893200

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Summary:High-end embedded systems, like their general-purpose counterparts, are turning to many-core cluster-based shared-memory architectures that provide a shared memory abstraction subject to non-uniform memory access (NUMA) costs. In order to keep the cores and memory hierarchy simple, many-core embedded systems tend to employ simple, scratchpad-like memories, rather than hardware managed caches that require some form of cache coherence management. These "coherence-free" systems still require some means to synchronize memory accesses and guarantee memory consistency. Conventional lock-based approaches may be employed to accomplish the synchronization, but may lead to both useability and performance issues. Instead, speculative synchronization, such as hardware transactional memory, may be a more attractive approach. However, hardware speculative techniques traditionally rely on the underlying cache-coherence protocol to synchronize memory accesses among the cores. The lack of a cache-coherence protocol adds new challenges in the design of hardware speculative support. In this paper, we present a new scheme for hardware transactional memory support within a cluster-based NUMA system that lacks an underlying cache-coherence protocol. To the best of our knowledge, this is the first design for speculative synchronization for this type of architecture. Through a set of benchmark experiments using our simulation platform, we show that our design can achieve significant performance improvements over traditional lock-based schemes.
DOI:10.1109/SAMOS.2014.6893200