Adaptive hierarchical cache policy in a microprocessor

摘要

A method for determining an inclusion policy includes determining a ratio of a capacity of a large cache to a capacity of a core cache in a cache subsystem of a processor and selecting an inclusive policy as the inclusion policy for the cache subsystem in response to the cache ratio exceeding an inclusion threshold. The method may further include selecting a non-inclusive policy in response to the cache ratio not exceeding the inclusion threshold and, responsive to a cache transaction resulting in a cache miss, performing an inclusion operation that invokes the inclusion policy.

主权项

1. A processor comprising:
a first storage to store a cache ratio indicator indicative of a ratio of a capacity of a second cache to a capacity of a core cache; a processing core including the core cache; the second cache; and a cache controller, including:
a core eviction unit to respond to an eviction of a clean and valid cache line from the core cache by performance of an operation selected, based on a value of the cache ratio indicator, from: an inclusive eviction operation comprising:
to silently drop the clean and valid cache line from the core cache; anda non-inclusive eviction operation comprising:
to update the second cache to include the clean and valid cache line;a state unit to respond to a core cache miss of a targeted line, valid and modified line in the second cache, by performance of an operation selected, based on the value of the cache ratio indicator, from:a first inclusive modified operation comprising:
allocation of a core cache line to store the targeted line in an exclusive state and fill the core cache line from the valid and modified line in the second cache; anda first non-inclusive modified operation comprising:
allocation of a core cache line to store the targeted line in a modified state, forward the core cache line in the second cache to the core cache, and invalidate the valid and modified line in the second cache.