Intel Corporation

Derek T Bachand

David Lawrence Hill

Chinna B Prudvi

Paul D Breuder

Matthew A Fisch

Robert J Greiner

Deborah T Marr

Michael T Klinglesmith

Tim Frodsham

Anant S Deval

Jose Niell

Ramadass Nagarajan

Ganesh Kumar

Chih-Hung Chung

Brent E Lince

Gururaj Shamanna

Mark R Waggoner

Harish Kumar

Quinn W Merrill

In an example, a system-on-a-chip comprises a plurality of multi-core processors, such as four dual-core processors for eight total cores. Each of the processors connects to shared resources such as memory and peripherals via a shared uncore fabric. Because each input bus for each core can include hundreds of data lines, the number of lines into the shared uncore fabric can become prohibitive. Thus, inputs from each core are multiplexed, such as in a two-to-one configuration. The multiplexing may be a non-blocking, queued (such as FIFO) multiplexing to ensure that all packets from all cores are delivered to the uncore fabric. In certain embodiment, some smaller input lines may be provided to the uncore fabric non-multiplexed, and returns (outputs) from the uncore fabric to the cores may also be non-multiplexed.

Low overhead hierarchical connectivity of cache coherent agents to a coherent fabric

In one embodiment, the present invention includes a method for writing data from a writer coupled to a reader via an in-die interconnect into a queue entry according to a first clock of the writer, generating a mapping of which second clocks of the reader that the reader is allowed to read from the queue, based at least in part on the first and second clocks, and reading the data from the entry at an allowed second clock. Other embodiments are described and claimed.

Communicating via an in-die interconnect

A processing agent is used in a system that transfers data of a predetermined data line length during external transactions. The agent may include an internal cache having a plurality of cache entries. Each cache entry may store multiple data line lengths of data. The agent further may include a transaction queue system having queue entries that include a primary entry including an address portion and status portion, the status portion provided for a first external transaction of the agent, and a secondary entry including a status portion provided for a second external transaction.

Transaction manager and cache for processing agent

A scheduler stores data to be scheduled. The scheduler may include an array that identifies relative priorities among the queue entries according to a first priority scheme, such as by age. The scheduler also may include a priority register array identifying relative priorities among the queue entries according to a second priority scheme, such as by data type. A plurality of detectors coupled to the array and to the priority register array may determine which data is to be scheduled next.

Prioritized bus request scheduling mechanism for processing devices

A multi-mode transaction queue may operate according to a default priority scheme. When a congestion event is detected, the transaction queue may engage a second priority scheme.

Dynamic priority external transaction system

Increased efficiency in a multiple agent system is provided by allowing all explicit writebacks to continue during a snoop phase. Upon each incoming external bus request, an agent determines if the address of that request matches an address of data within the agent. If there is a match, the agent copies this most recent data, changes the state of the data to unmodified, changes the length of the data to zero (for pending explicit writebacks), and performs an implicit writeback. Additionally, prior to each explicit writeback, an agent determines if the address of the explicit writeback and any incoming snoop request requests are the same. If there is a match, the agent changes the data length of the explicit writeback to zero prior to issuing the explicit writeback.

Method and apparatus for altering data length to zero to maintain cache coherency

A transaction management system is described for scheduling requests on an external bus. The system includes a number of queue registers to store requests and a controller coupled to queue registers to schedule external bus transactions for an agent that processes read requests, prefetch requests and write requests. The controller posts at least one write request to an external bus every defined number of transactions if at least one non-posted write request is stored in the queue registers.

External bus transaction scheduling system

In a method of processing a bus transaction, an address is retrieved from the bus transaction and referred to a queue of pending transaction. A match indicator signal is returned from the queue. If the match indicator signal indicates a match, a snoop probe for the bus transaction is blocked.

Growing community of inventors

Portland, OR, United States of America

Derek T Bachand