Modeling LRU cache with invalidation

Our work allows us to conclude that the presence of invalidation events does not severely impact the LRU performance in single caches. As a matter of fact, invalidation effects can be ignored there, unless the invalidation rate is comparable with the request rate and the per-object invalidation rate and request rate are highly correlated. However, in the case of hierarchical caching, even a limited effect of invalidation on first-level caches is sufficient to noticeably affect the performance of second level/downstream caches.