Smart Cache

About: Smart Cache is a research topic. Over the lifetime, 7680 publications have been published within this topic receiving 180618 citations.

The V-Way Cache: Demand Based Associativity via Global Replacement

Abstract: As processor speeds increase and memory latency becomes more critical, intelligent design and management of secondary caches becomes increasingly important. The efficiency of current set-associative caches is reduced because programs exhibit a non-uniform distribution of memory accesses across different cache sets. We propose a technique to vary the associativity of a cache on a per-set basis in response to the demands of the program. By increasing the number of tag-store entries relative to the number of data lines, we achieve the performance benefit of global replacement while maintaining the constant hit latency of a set-associative cache. The proposed variable-way, or V-Way, set-associative cache achieves an average miss rate reduction of 13% on sixteen benchmarks from the SPEC CPU2000 suite. This translates into an average IPC improvement of 8%.

The ZCache: Decoupling Ways and Associativity

Abstract: The ever-increasing importance of main memory latency and bandwidth is pushing CMPs towards caches with higher capacity and associativity. Associativity is typically improved by increasing the number of ways. This reduces conflict misses, but increases hit latency and energy, placing a stringent trade-off on cache design. We present the zcache, a cache design that allows much higher associativity than the number of physical ways (e.g. a 64-associative cache with 4 ways). The zcache draws on previous research on skew-associative caches and cuckoo hashing. Hits, the common case, require a single lookup, incurring the latency and energy costs of a cache with a very low number of ways. On a miss, additional tag lookups happen off the critical path, yielding an arbitrarily large number of replacement candidates for the incoming block. Unlike conventional designs, the zcache provides associativity by increasing the number of replacement candidates, but not the number of cache ways. To understand the implications of this approach, we develop a general analysis framework that allows to compare associativity across different cache designs (e.g. a set-associative cache and a zcache) by representing associativity as a probability distribution. We use this framework to show that for zcaches, associativity depends only on the number of replacement candidates, and is independent of other factors (such as the number of cache ways or the workload). We also show that, for the same number of replacement candidates, the associativity of a zcache is superior than that of a set-associative cache for most workloads. Finally, we perform detailed simulations of multithreaded and multiprogrammed workloads on a large-scale CMP with zcache as the last-level cache. We show that zcaches provide higher performance and better energy efficiency than conventional caches without incurring the overheads of designs with a large number of ways.

Improving web server performance by caching dynamic data

Abstract: Dynamic Web pages can seriously reduce the performance of Web servers. One technique for improving performance is to cache dynamic Web pages. We have developed the Dynamic Web cache which is particularly well-suited for dynamic pages. Our cache has improved performance significantly at several commercial Web sites. This paper analyzes the design and performance of the DynamicWeb cache. It also presents a model for analyzing overall system performance in the presence of caching. Our cache can satisfy several hundred requests per second. On systems which invoke server programs via CGI, the DynamicWeb cache results in near-optimal performance, where optimal performance is that which would be achieved by a hypothetical cache which consumed no CPU cycles. On a system we tested which invoked server programs via ICAPI which has significantly less overhead than CGI, the DynamicWeb cache resulted in near-optimal performance for many cases and 58% of optimal performance in the worst case. The DynamicWeb cache achieved a hit rate of around 80% when it was deployed to support the official Internet Web site for the 1996 Atlanta Olympic games.

The influence of caches on the performance of sorting

Abstract: We investigate the effect that caches have on the performance of sorting algorithms both experimentally and analytically. To address the performance problems that high cache miss penalties introduce we restructure mergesort, quicksort, and heapsort in order to improve their cache locality. For all three algorithms the improvement in cache performance leads to a reduction in total execution time. We also investigate the performance of radix sort. Despite the extremely low instruction count incurred by this linear time sorting algorithm, its relatively poor cache performance results in worse overall performance than the efficient comparison based sorting algorithms. For each algorithm we provide an analysis that closely predicts the number of cache misses incurred by the algorithm.

Breadcrumbs: Efficient, Best-Effort Content Location in Cache Networks

Abstract: For several years, web caching has been used to meet the ever-increasing Web access loads. A fundamental capability of all such systems is that of inter-cache coordination, which can be divided into two main types: explicit and implicit coordination. While the former allows for greater control over resource allocation, the latter does not suffer from the additional communication overhead needed for coordination. In this paper, we consider a network in which each router has a local cache that caches files passing through it. By additionally storing minimal information regarding caching history, we develop a simple content caching, location, and routing systems that adopts an implicit, transparent, and best-effort approach towards caching. Though only best effort, the policy outperforms classic policies that allow explicit coordination between caches.