Hint-based Acceleration of Web Proxy Caches

Numerous studies show that proxy cache miss ratios are typically at least 40%-50%. This paper proposes and evaluates a new approach for improving the throughput of proxy caches by reducing cache miss overheads. An embedded system able to achieve sig-niicantly better communications performance than a traditional proxy lters the requests directed to a proxy cache, forwarding the hits to the proxy and processing the misses itself. This system, which we call a proxy accelerator, uses hints of the proxy cache content and may include a main memory cache for the hottest objects. Scalability with the Web proxy cluster size is achieved by using several accelerators. We use analytical models and trace-based simulations to study the beneets of this scheme and the potential impacts of hint-related mechanisms. Our proxy accelerator results in signiicant performance improvements. A single proxy accelerator node in front of a four-node Web proxy improves throughput by about 100%.