Let me respond to this comment from the article: """ This is not the case for Chrome: the browser keeps all the cached information indefinitely; perhaps this is driven by some hypothetical assumptions about browsing performance, and perhaps it simply is driven by the desire to collect more information to provide you with more relevant ads. Whatever the reason, the outcome is simple: over time, cache lookups get progressively more expensive; some of this is unavoidable, and some may be made worse by a faulty hash map implementation in infinite_cache.cc. """
Chromium (and thereby, Google Chrome) does not cache forever. The author is clearly misled by the infinite_cache.cc file he referenced. That is our experiment file, designed to examine a theoretical "infinite" cache's performance for data gathering purposes. It doesn't actually cache the resources, but just records the keys (basically, the URL). It only runs on a small set of user browser sessions (only for users who opt-in to helping make Google Chrome better and a subset of their browsing sessions).
As my previous Google+ post mentions (thanks for the parent for linking it), we cap the cache size at 320MB. The author is simply factually incorrect about the aforementioned claim.
As for cache performance as the cache gets larger, I fully believe that it gets slower. We have data that backs up this assertion. Of course, larger caches means that more gets cached. And there are ways to restructure the cache implementation to avoid the painful latency on cache misses. While cache misses are indeed a large percent of resource requests, it is misguided to analyze the cost of cache misses in isolation. For the opposite argument about how we should be increasing cache sizes, see Steve Souders' posts: http://www.stevesouders.com/blog/2012/10/11/cache-is-king/, http://www.stevesouders.com/blog/2012/03/22/cache-them-if-yo..., etc.
The caching issues are far more complicated than described in the original post. The data is much appreciated, and we have similar data that we're looking at as we're making our decisions about caching.