×

System for minimizing directory information in scalable multiprocessor systems with logically independent input/output nodes

  • US 6,738,868 B2
  • Filed: 01/07/2002
  • Issued: 05/18/2004
  • Est. Priority Date: 06/10/2000
  • Status: Expired due to Fees
First Claim
Patent Images

1. A multiprocessor computer system comprising a plurality of nodes,each node including:

  • an interface to a local memory subsystem, the local memory subsystem storing a multiplicity of memory lines of information and a directory, said directory configured to store sharing information concerning a memory line of information stored in the local memory subsystem;

    a memory cache for caching a multiplicity of memory lines of information, including memory lines of information stored in a remote memory subsystem that is local to another node;

    a protocol engine implementing a negative acknowledgment free cache coherence protocol, the protocol engine including a memory transaction array for storing an entry related to a memory transaction, the entry including a memory transaction state, the memory transaction concerning a memory line of information;

    logic for processing the memory transaction, including advancing the memory transaction when predefined criteria are satisfied and storing a state of the memory transaction in the memory transaction array;

    a first subset of nodes comprising one or more nodes from said plurality of nodes, each node in said first subset including an interface to one or more I/O devices;

    the protocol engine included in each node from said first subset of nodes is configured to limit to a predefined period of time, any sharing of a memory line of information stored in the remote memory subsystem that is local to a home node from said plurality of nodes; and

    the protocol engine included in the home node is configured to identify only nodes other than nodes in the first subset that are sharing the memory line of information.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×