# On a caching system with object sharing

## TL;DR

This paper analyzes a shared caching system with multiple proxies, proposing a model to estimate cache-hit probabilities considering object sharing, and introduces methods to reduce eviction overhead, supported by numerical results from a prototype.

## Contribution

It introduces a 'working-set' approximation for shared cache systems with object sharing, aiding in cache management and admission control.

## Key findings

- The approximation accurately estimates cache-hit probabilities.
- Object sharing among proxies affects cache performance.
- Proposed methods reduce ripple evictions and request overhead.

## Abstract

We consider a content-caching system thatis shared by a number of proxies. The cache could belocated in an edge-cloud datacenter and the proxies couldeach serve a large population of mobile end-users. Eachproxy operates its own LRU-list of a certain capacity inthe shared cache. The length of objects simultaneouslyappearing in plural LRU-lists is equally divided amongthem,i.e., object sharing among the LRUs. We provide a "working-set" approximation for this system to quicklyestimate the cache-hit probabilities under such objectsharing, which can be used to facilitate admission control.Also, a way to reduce ripple evictions,i.e.,setrequestoverhead, is suggested. We give numerical results for ourMemCacheD with Object Sharing (MCD-OS) prototype.