US 12,072,805 B2
System and method to enter and exit a cache coherent interconnect
Mohammed Khaleeluddin, Union City, CA (US); and Michael Frank, Sunnyvale, CA (US)
Assigned to ARTERIS, INC., Campbell, CA (US)
Filed by ARTERIS, INC., Campbell, CA (US)
Filed on Apr. 11, 2022, as Appl. No. 17/717,148.
Prior Publication US 2023/0325316 A1, Oct. 12, 2023
Int. Cl. G06F 12/0817 (2016.01)
CPC G06F 12/0828 (2013.01) [G06F 2212/621 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method of communicating an agent's coherency state when the agent is within a cache coherent environment, which is using an interconnect, and the agent is capable of exiting the cache coherent environment the method comprising:
generating, at the agent in communication with a network interface unit (NIU) and the NIU is in communication with the interconnect, a signal that indicates that the agent is doing one of entering the cache coherent environment or exiting the cache coherent environment;
generating, in response to the signal, an initial message using a message builder of the NIU;
transmitting, using the interconnect, the initial message to a directory, which is in communication with the interconnect and includes a tracking engine that tracks a plurality of agents within the cache coherent environment;
sending, from the directory to the agent, an acknowledgement message indicating that the signal was received thereby allowing the agent to exit the cache coherent environment; and
preventing, using the tracking engine, snoops from being sent to the agent when the initial message indicates the agent is exiting the cache coherent environment.