Oracle America, Inc.

Sandip Das

Sanjay Patel

Prashant Jain

Srinivasan R Iyengar

Yoganand Chillarige

Shukur Moulali Pathan

A processor may include several processor cores, each including a respective higher-level cache, wherein each higher-level cache includes higher-level cache lines; and a lower-level cache including lower-level cache lines, where each of the lower-level cache lines may be configured to store data that corresponds to multiple higher-level cache lines. In response to invalidating a given lower-level cache line, the lower-level cache may be configured to convey a sequence including several invalidation packets to the processor cores via an interface, where each member of the sequence of invalidation packets corresponds to a respective higher-level cache line to be invalidated, and where the interface is narrower than an interface capable of concurrently conveying all invalidation information corresponding to the given lower-level cache line. Each invalidation packet may include invalidation information indicative of a location of the respective higher-level cache line within different ones of the processor cores.

Reducing implementation costs of communicating cache invalidation information in a multicore processor

A processor may include several processor cores, each including a respective higher-level cache; a lower-level cache including several tag units each including several controllers, where each controller corresponds to a respective cache bank configured to store data, and where the controllers are concurrently operable to access their respective cache banks; and an interconnect network configured to convey data between the cores and the lower-level cache. The controllers in a given tag unit may share access to a resource that may include one or more of an interconnect egress port coupled to the interconnect network, an interconnect ingress port coupled to the interconnect network, a test controller, or a data storage structure.

Resource sharing to reduce implementation costs in a multicore processor

A processor may include several processor cores, each including a respective higher-level cache; a lower-level cache including several tag units each including several controllers, where each controller corresponds to a respective cache bank configured to store data, and where the controllers are concurrently operable to access their respective cache banks; and an interconnect network configured to convey data between the cores and the lower-level cache. The controllers may share access to an interconnect egress port coupled to the interconnect network, and may generate multiple concurrent requests to convey data via the shared port, where each of the requests is destined for a corresponding core, and where a datapath width of the port is less than a combined width of the multiple requests. The given tag unit may arbitrate among the controllers for access to the shared port, such that the requests are transmitted to corresponding cores serially rather than concurrently.

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Belmont, CA, United States of America

Sandip Das