𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Techniques for Improving Performance of Hybrid Snooping Cache Protocols

✍ Scribed by Fredrik Dahlgren


Publisher
Elsevier Science
Year
1999
Tongue
English
Weight
522 KB
Volume
59
Category
Article
ISSN
0743-7315

No coin nor oath required. For personal study only.

✦ Synopsis


Bus-based multiprocessors constitute a cost-effective class of sharedmemory multiprocessors. Private caches are the key to an efficient utilization of the shared bus, and most such systems use a write-invalidate cache-coherence protocol to keep the caches coherent. Two important factors that limit the performance of the system are cache misses that lead to long-latency reads and bus congestion because of read misses and coherence traffic. While hybrid write-invalidateΓ‚write-update snooping protocols lead to fewer read misses than write-invalidate protocols, previous studies have shown them to be incapable of providing consistent performance improvements because of heavily increased coherence traffic. In this paper, we analyze how the deficiencies of hybrid snooping protocols can be dramatically reduced by using write caches and read snarfing (also called read-broadcast) under release consistency. Our performance evaluation is based on program-driven simulation and a set of five scientific applications with different sharing behaviors including migratory sharing as well as producer consumer sharing. We show that one of the evaluated hybrid protocols, extended with write caches as well as read snarfing, manages to reduce the number of coherence misses by between 83 and 93 0 as compared to a write-invalidate protocol for all five applications in this study. In addition, the number of bus transactions is reduced substantially. However, we also show that read snarfing and hybrid snooping protocols might lead to higher cache occupancy because of increased sharing. Because of the small implementation cost of the hybrid protocol and the two extensions, we believe the combination to be an effective approach to boosting the performance of bus-based multiprocessors.


πŸ“œ SIMILAR VOLUMES


A difference frequency technique for imp
✍ Djuradj Budimir; M. Modeste; Colin S. Aitchison πŸ“‚ Article πŸ“… 2000 πŸ› John Wiley and Sons 🌐 English βš– 120 KB πŸ‘ 2 views

A difference frequency technique for reducing the IM product le¨els in a nonlinear RF amplifier is presented. The technique is based on the standard two-tone test. The two sinusoid signals together with their difference frequency signal are fed into the amplifier. CAD simulation shows that the third