International Business Machines Corporation

John Thomas Hollaway, Jr

Charles Francis Marino

Guy L Guthrie

Praveen S Reddy

William John Starke

Jeffrey A Stuecheli

David John Krolak

Michael Steven Siegel

Eric Eugene Retter

Derek E Williams

Sanjeev Ghai

Paul Allen Ganfield

Daniel C Howe

James Stephen Fields, Jr

Edgar Rolando Cordero

Mark Edward Dean

Mark Andrew Brittain

Yoanna Baumgartner

Alvaro Eduardo Benavides

A symmetric multiprocessor includes with a hierarchical ring-based interconnection network is disclosed. The symmetric processor includes a plurality of buses comprised on the symmetric multiprocessor, wherein each of the buses are configured in a circular topology. The symmetric multiprocessor also includes a plurality of multi-processing nodes interconnected by the buses to make a hierarchical ring-based interconnection network for conveying commands between the multi-processing nodes. The interconnection network includes a command network configured to transport commands based on command tokens, wherein the tokens dictate a destination of the command, a partial response network configured to transport partial responses generated by the multi-processing nodes, and a combined response network configured to combine the partial responses generated by the multi-processing nodes using combined response tokens.

Hierarchical ring-based interconnection network for symmetric multiprocessors

A coherency error detection and reporting mechanism monitors for coherency errors in a processor and between processors. When a requestor broadcasts a memory address in a command and a coherency error is detected, information regarding the command that caused the coherency error is logged, and the coherency error is reported a system error handler. The information logged for the coherency error may include the address of the coherency error, the requestor, the command, the response to the command, the scope of the coherency error, the error type, etc. Logging information relating to the coherency error provides more information to a person analyzing the processor for failures to more easily track down the cause of coherency errors.

Coherency error detection and reporting in a processor

In one or more embodiments, one or more systems, devices, methods, and/or processes described can send, via an interconnect, a rate master command to at least one of multiple processing nodes; determine that a message indicating a dropped command, associated with the rate master command, is received; determine that a count, associated with dropped commands, satisfies a threshold; and provide, to the processing nodes via the interconnect, a signal indicating a command rate, in response to determining that the count satisfies the threshold. Moreover, the count can be incremented in response to determining that the message is received. The at least one of multiple processing nodes can receive, via the interconnect, the signal indicating the command rate and can utilize the command rate in issuing speculative commands, via the interconnect.

Determining command rate based on dropped commands

In response to snooping a read-type memory access request of a requestor on a system fabric of a data processing system, a memory channel interface forwards the request to a memory buffer and starts a timer. In response to the forwarded request, the memory buffer performs a lookup of a target address of the request in a memory controller cache. In response to the target address hitting in a coherence state permitting provision of early data, the memory buffer provides a response indicating early data and provides a copy of a target memory block of the request to the memory channel interface. The memory channel interface, responsive to receipt prior to expiration of the timer of the response indicating early data, transmits the copy of the target memory block to the requestor via the system fabric prior to receiving a combined response of the data processing system to the request.

Provision of early data from a lower level cache memory

One or more systems, devices, methods, and/or processes described can determine a maximum cache command rate of a processor unit. For example, an interface of the processor unit is configured to be coupled to an interconnect of a multiprocessor system and is configured such that a first portion of the interface provides a signal to a second portion of the interface, where the first portion of the interface operates utilizing a known frequency and the second portion of the interface operates utilizing a cache frequency of the processor unit; the second portion of the interface circulates the signal; the first portion of the interface receives the signal from the second portion of the interface; the first portion of the interface determines a cache command rate based on the known frequency, the frequency of the cache, and the signal; and the interface provides information indicating the cache command rate to the interconnect.

Frequency determination across an interface of a data processing system

One or more systems, devices, methods, and/or processes described can determine a maximum cache command rate of a processor unit. For example, an interface of the processor unit configured to be coupled to an interconnect of a multiprocessor system and configured such that a first portion of the interface provides a signal to a second portion of the interface, where the first portion of the interface operates utilizing a known frequency and the second portion of the interface operates utilizing a cache frequency of the processor unit; the second portion of the interface circulates the signal; the first portion of the interface receives the signal from the second portion of the interface; the first portion of the interface determines a cache command rate based on the known frequency, the frequency of the cache, and the signal; and the interface provides information indicating the cache command rate to the interconnect.

A data processing system includes a plurality of requestors and a memory controller for a system memory. In response to receiving from the requestor a read-type request targeting a memory block in the system memory, the memory controller protects the memory block from modification, and in response to an indication that the memory controller is responsible for servicing the read-type request, the memory controller transmits the memory block to the requestor. Prior to receipt of the memory block by the requestor, the memory controller ends protection of the memory block from modification, and the requestor begins protection of the memory block from modification. In response to receipt of the memory block, the requestor ends its protection of the memory block from modification.

Data processing system and method in which a participant initiating a read operation protects data integrity

A memory controller for a processing unit provides a memory wrap test mode path which selectively writes data from the write buffer of the controller to the read buffer of the controller, thereby allowing the write and read buffers to substitute for a system memory device during testing of the processing unit. The processing unit can thus be tested without the attached memory device yet still operate under conditions which generate bus traffic and chip noise similar to that generated under actual (end-use) operation. When a processor issues a write operation in test mode, the controller writes the data to an entry of the read buffer which corresponds to the write address. Thereafter, the processor can issue a read operation with the same address and the read buffer will send the data from the corresponding entry.

Memory wrap test mode using functional read/write buffers

A cache coherent data processing system includes at least first and second coherency domains. The first coherency domain contains a memory controller, an associated system memory having a target memory block identified by a target address, and a domain indicator indicating whether the target memory block is cached outside the first coherency domain. During operation, the first coherency domain receives a flush operation broadcast to the first and second coherency domains, where the flush operation specifies the target address of the target memory block. The first coherency domain also receives a combined response for the flush operation representing a system-wide response to the flush operation. In response to receipt in the first coherency domain of the combined response, a determination is made if the combined response indicates that a cached copy of the target memory block may remain within the data processing system. In response to a determination that the combined response indicates that a cached copy of the target memory block may remain in the data processing system, the domain indicator is updated to indicate that the target memory block is cached outside of the first coherency domain.

Data processing system, cache system and method for handling a flush operation in a data processing system having multiple coherency domains

A data processing system includes a memory controller of a system memory that receives first and second castout operations both specifying a same address. In response to receiving said first and second castout operations, the memory controller performs a single update to the system memory.

Data processing system and method for handling castout collisions

A method for supporting software partition and dynamic reconfiguration within a non-uniform memory access (NUMA) computer system is disclosed. A NUMA computer system includes multiple nodes coupled to an interconnect. Each of the nodes includes a NUMA bridge, a local system memory, and at least one processor having at least a local cache memory. Multiple groups of software partitions are formed within the NUMA computer system, and each of the software partitions is formed by a subset of the nodes. A destination map table is provided in a NUMA bridge of each of the nodes for keeping track of the nodes within a software partition. A command is forwarded to only the nodes within a software partition.

Growing community of inventors

Austin, TX, United States of America

John Thomas Hollaway, Jr