Hardware filter for tracking block presence in large caches

摘要

A system and method for efficiently determining whether a requested memory location is in a large row-based memory of a computing system. A computing system includes a processing unit that generates memory requests on a first chip and a cache (LLC) on a second chip connected to the first chip. The processing unit includes an access filter that determines whether to access the cache. The cache is fabricated on top of the processing unit. The processing unit determines whether to access the access filter for a given memory request. The processing unit accesses the access filter to determine whether given data associated with a given memory request is stored within the cache. In response to determining the access filter indicates the given data is not stored within the cache, the processing unit generates a memory request to send to off-package memory.

主权项

1. A computing system comprising:
a processing unit on a first chip configured to generate memory requests, wherein the processing unit includes an access filter; and a cache on a second chip, wherein the cache is coupled to the first chip in a package; wherein the processing unit is configured to:
determine whether to access the access filter for a given memory request based on a hit rate of the cache, the access filter being configured to store information that indicates whether the cache includes data corresponding to a memory request;in response to determining the hit rate is below a given threshold:
access the access filter to determine whether data corresponding to the memory request is stored in the cache;in response to determining the hit rate is above the given threshold:
forgo access of the access filter; andgenerate a memory access to the cache.