Evaluating The Performance Of Four Snooping Cache Coherency Protocols

Write-invalidate and write-broadcast coherency protocols have been criticized for being unable to achieve good bus performance across all cache configurations. In particular, write-invalidate performance can suffer as block size increases; and large cache sizes will hurt write-broadcast. Read-broadc...

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Bibliographic Details
Published inThe 16th Annual International Symposium on Computer Architecture pp. 2 - 15
Main Authors Eggers, S.J., Katz, R.H.
Format Conference Proceeding
LanguageEnglish
Published IEEE 1989
Subjects
Broadcasting
Computer science
Costs
Degradation
Distributed computing
Machinery
Performance loss
Permission
Protocols
Size measurement
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Summary:Write-invalidate and write-broadcast coherency protocols have been criticized for being unable to achieve good bus performance across all cache configurations. In particular, write-invalidate performance can suffer as block size increases; and large cache sizes will hurt write-broadcast. Read-broadcast and competitive snooping extensions to the protocols have been proposed to solve each problem. Our results indicate that the benefits of the extensions are limited. Read-broadcast reduces the number of invalidation misses, but at a high cost in processor lockout from the cache. The net effect can be an increase in total execution cycles. Competitive snooping benefits only those programs with high per-processor locality Of reference to shared data. For programs characterized by inter-processor contention for shared addresses, competi- tive snooping can degrade performance by causing a slight increase in bus utilization and total execution time.
ISBN:081868948X
9780818689482
ISSN:1063-6897
2575-713X
DOI:10.1109/ISCA.1989.714519