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4 Performance Evaluation 

This section evaluates the performance of HAC based on the usual analytical model of cache performance:

Access time = Hit time + Miss rate x Miss penalty

Here, hit time is the average time to access an object that is present in the client cache and is fully converted to the in-cache format, miss rate is the average number of page fetches per object access, and miss penalty is the average time to service a client cache miss.

We analyze the performance of HAC by evaluating its effect on each of the terms in the formula. Section 4.2 shows that HAC achieves lower miss rates than page-caching systems and dual-buffering schemes proposed in the literature. Sections 4.3 and 4.4 examine the overhead introduced by HAC on hit time and miss penalty. Section 4.5 analyzes the overall performance of our system, and Section 4.6 shows how it performs when objects are both read and written.

Miguel Castro, Atul Adya, Barbara Liskov, and Andrew Myers

Copyright ©1997 by the Association for Computing Machinery