Shared Memory Architecture

Shared memory systems form a major category of multiprocessors. In this category, all processors share a global memory. Communication between tasks running on different processors is performed through writing to and reading from the global memory. All inter‐processor coordination and synchronization...

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Veröffentlicht in:Advanced Computer Architecture and Parallel Processing S. 77 - 102
Hauptverfasser: El‐Rewini, Hesham, Abd‐El‐Barr, Mostafa
Format: Buchkapitel
Sprache:Englisch
Veröffentlicht: Hoboken, NJ, USA John Wiley & Sons, Inc 17.12.2004
Schriftenreihe:Wiley Series on Parallel and Distributed Computing
Schlagworte:
basic cache coherency methods
bus based symmetric multiprocessors
cache‐only memory architecture (COMA)
directory based protocols
non‐uniform memory access (NUMA)
shared memory programming
shared‐memory classification schemes
shared‐memory multiprocessors
snooping protocols
uniform memory access (UMA)
ISBN:9780471467403, 0471467405
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Beschreibung
Zusammenfassung:Shared memory systems form a major category of multiprocessors. In this category, all processors share a global memory. Communication between tasks running on different processors is performed through writing to and reading from the global memory. All inter‐processor coordination and synchronization are also accomplished via the global memory. A shared memory computer system consists of a set of independent processors, a set of memory modules, and an interconnection network. Two main problems need to be addressed when designing a shared memory system: performance degradation due to contention, and coherence problems. Performance degradation might happen when multiple processors are trying to access the shared memory simultaneously. A typical design might uses caches to solve the contention problem. However, having multiple copies of data, spread throughout the caches, might lead to a coherence problem. The copies in the caches are coherent if they all equal the same value. But, if one of the processors writes over the value of one of the copies, then the copy becomes inconsistent because it no longer equals the value of the other copies. In this chapter we study a variety of shared memory systems and their solutions of the cache coherence problem. The aspects studied include Uniform Memory Access (UMA), Non‐uniform memory access (NUMA), Cache‐only memory Architecture (COMA), Bus Based Symmetric Multiprocessors, Basic Cache Coherency Methods, Snooping Protocols, Directory Based Protocols, and Shared Memory Programming.
ISBN:9780471467403
0471467405
DOI:10.1002/0471478385.ch4