Scalable cache coherency protocol
    12.
    发明授权

    公开(公告)号:US11544193B2

    公开(公告)日:2023-01-03

    申请号:US17315725

    申请日:2021-05-10

    Applicant: Apple Inc.

    Abstract: A scalable cache coherency protocol for system including a plurality of coherent agents coupled to one or more memory controllers is described. The memory controller may implement a precise directory for cache blocks from the memory to which the memory controller is coupled. Multiple requests to a cache block may be outstanding, and snoops and completions for requests may include an expected cache state at the receiving agent, as indicated by a directory in the memory controller when the request was processed, to allow the receiving agent to detect race conditions. In an embodiment, the cache states may include a primary shared and a secondary shared state. The primary shared state may apply to a coherent agent that bears responsibility for transmitting a copy of the cache block to a requesting agent. In an embodiment, at least two types of snoops may be supported: snoop forward and snoop back.

    I/O Agent
    13.
    发明申请

    公开(公告)号:US20220318136A1

    公开(公告)日:2022-10-06

    申请号:US17648071

    申请日:2022-01-14

    Applicant: Apple Inc.

    Abstract: Techniques are disclosed relating to an I/O agent circuit of a computer system. The I/O agent circuit may receive, from a peripheral component, a set of transaction requests to perform a set of read transactions that are directed to one or more of a plurality of cache lines. The I/O agent circuit may issue, to a first memory controller circuit configured to manage access to a first one of the plurality of cache lines, a request for exclusive read ownership of the first cache line such that data of the first cache line is not cached outside of the memory and the I/O agent circuit in a valid state. The I/O agent circuit may receive exclusive read ownership of the first cache line, including receiving the data of the first cache line. The I/O agent circuit may then perform the set of read transactions with respect to the data.

    Remote Cache Invalidation
    14.
    发明申请

    公开(公告)号:US20250103492A1

    公开(公告)日:2025-03-27

    申请号:US18582305

    申请日:2024-02-20

    Applicant: Apple Inc.

    Abstract: Techniques are disclosed relating to performing remote cache invalidations. In some embodiments, primary processor circuitry is configured to, based on execution of a remote invalidate instruction (e.g., an ISA-defined instruction), send a cache invalidate command to coprocessor circuitry. The coprocessor circuitry includes coprocessor cache circuitry and cache invalidation control circuitry configured to, in response to the cache invalidate command sent by the primary processor, invalidate one or more cache lines in the coprocessor cache circuitry without executing any instructions on the coprocessor circuitry.

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