Scarfing within a hierarchical memory architecture
AssigneeInternational Business Machines Corporation
InventorsRavi Kumar Arimilli, John Steven Dodson, Jerry Don Lewis
Life of this patent
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Abstract
A method and system for scarfing data during a data access transaction within a hierarchical data storage system. A data access request is delivered from a source device to a plurality of data storage devices. The access request includes a target address and a source path tag, wherein the source path tag includes a device identification tag that uniquely identifies a data storage device within a given level of the system traversed by the access request. A device identification tag that uniquely identifies the third party transactor within a given memory level is appended to the source path tag such that the third party transactor can scarf returning data without reserving a scarf queue entry.
Claims17
A method for enabling a third party transactor to scarf data during a transaction within a hierarchical data storage system, said method comprising:
- delivering a data access request from a source device onto an address bus of said hierarchical data storage system, wherein said data access request includes a target address and a source path tag uniquely identifying at least one data storage device within two or more levels of said hierarchical data storage system;
- appending by said third party transactor an identification tag within said data access request in response to a snooping of said data access request;
- delivering a data access response onto a data bus, wherein said response includes said source path tag and said target address;
- and
- using the device identification tag, determine whether said third party transactor can scarf returning data.
A system for enabling a third party transactor to scarf data during a transaction within a hierarchical data storage system, said system comprising:
- processing means for delivering a data access request from a source device onto an address bus of said hierarchical data storage system, wherein said data access request includes a target address and a source path tag uniquely identifying at least one data storage device within two or more levels of said hierarchical data storage system;
- processing means for appending by said third party transactor an identification tag within said data access request in response to a snooping of said data access request;
- processing means for delivering a data access response onto a data bus, wherein said response includes said source path tag and said target address;
- and
- processing means for using the device identification tag to determine whether said third party transactor can scarf returning data.
Dependencies are inferred from the claim text.