International Business Machines Corporation

Wayne Melvin Barrett

Florian Alexander Auernhammer

Robert Allen Drehmel

Michael Steven Siegel

Brian Thomas Vanderpool

Kenneth Michael Valk

Joseph Allen Kirscht

David Alan Shedivy

Elizabeth A McGlone

Todd Alan Greenfield

Guy L Guthrie

William John Starke

Dong Chen

Paul William Coteus

Alan G Gara

Richard Loise Arndt

Philip Rogers Hillier, Iii

Gerard Vincent Kopcsay

Rory D Jackson

Ben Jesse Nathanson

Gerald Keith Bartley

Daniel Frank Moertl

Todd Edward Takken

Paul Eric Dahlen

Bruce Leroy Beukema

Pavlos Michael Vranas

James Anthony Marcella

Daniel Wind

Douglas A Baska

William E Hammer

Brian David Allison

Kenneth Claude Hinz

Gene Leung

Paylos Michael Vranas

Asynchronous completion notification is provided in a data processing system including one or more cores each executing one or more threads. A hardware unit of the data processing system receives and enqueues a request for processing and a source tag indicating at least a thread and core that issued the request. The hardware unit maintains a pointer to a completion area in a memory space. The completion area includes a completion granule for the hardware unit and thread. The hardware unit performs the processing requested by the request and computes an address of the completion granule based on the pointer and the source tag. The hardware unit then provides completion notification for the request by updating the completion granule with a value indicating a completion status.

Asynchronous completion notification in a multi-core data processing system

A plurality of virtual processor threads are executed on the plurality of physical processor threads. In a data structure, information pertaining to a plurality of interrupt sources in the data processing system is maintained. The information includes a historical scope of transmission of interrupt commands for an interrupt source. Based on an interrupt request from an interrupt source, an interrupt master transmits a first interrupt bus command on an interconnect fabric of the data processing system to poll one or more interrupt snoopers regarding availability of one or more of the virtual processor threads to service an interrupt. The interrupt master updates the scope of transmission specified in the data structure based on a combined response to the first interrupt bus command. The interrupt master applies the scope of transmission specified in the data structure to a subsequent second interrupt bus command for the interrupt source.

Efficient selection of a particular processor thread for handling an interrupt

A snooper of a processing unit connected to processing units via a system fabric receives a first single bus command in a bus protocol that allows sampling over the system fabric of the capability of snoopers to handle an interrupt and returns a first response indicating the capability of the snooper to handle the interrupt. The snooper, in response to receiving a second single bus command in the bus protocol to poll a first selection of snoopers for an availability status to service a criteria specified in the second single bus command, returns a second response indicating the availability of the snooper to service the criteria. The snooper, in response to receiving a third single bus command in the bus protocol to direct the snooper to handle the interrupt, assigns the interrupt to a particular processor thread of a respective selection of the one or more separate selections of processors threads distributed in the processing unit.

Managing efficient selection of a particular processor thread for handling an interrupt

A technique for handling interrupts in a data processing system includes receiving, by an interrupt routing controller (IRC), an event routing message (ERM) that includes an event source number for a notification source with an unserviced interrupt. In response to receiving the ERM, the IRC builds an event notification message (ENM) based on the event source number. The IRC determines a scope for the ENM based on an event target group (ETG) associated with the event source number. The IRC issues the ENM to an interrupt presentation controller (IPC) at the scope associated with the ETG.

Techniques for issuing interrupts in a data processing system with multiple scopes

A processing unit connected via a system fabric to multiple processing units calls a first single command in a bus protocol that allows sampling over the system fabric of the capability of snoopers distributed across the processing units to handle an interrupt. The processing unit, in response to detecting at least one first selection of snoopers with capability to handle the interrupt, calling a second single command in the bus protocol to poll the first selection of snoopers over the system fabric for an availability status. The processing unit, in response to detecting at least one second selection of snoopers respond with the available status indicating an availability to handle the interrupt, assigning a single snooper from among the second selection of snoopers to handle the interrupt by calling a third single command in the bus protocol.

System, computer program product, and computer-implemented method to improve a running disparity of an encoded bit stream in a distributed network switch, the distributed network switch comprising a plurality of switch modules including a first switch module, by receiving, at the first switch module, a raw data stream comprising a plurality of bits, receiving a bit sequence, encoding at least a first bit of the raw data stream using a corresponding at least a first bit of the bit sequence, transmitting the encoded first bit, inverting the first bit of the bit sequence, and encoding a second bit of the raw data stream using the inverted first bit.

Disparity reduction for high speed serial links

A method and circuit for implementing known scrambling relationship among multiple serial links, and a design structure on which the subject circuit resides are provided. A transmit Linear Feedback Shift Register (LFSR) is provided with each of the multiple serial links for scrambling transmitted data. A receive Linear Feedback Shift Register (LFSR) is provided with each of the multiple serial links for descrambling received data. Each of the transmit LFSRs is initialized to a unique value. Each transmit LFSR conveys a current unique value to a receive LFSR for synchronizing the transmit LFSR and receive LFSR to begin scrambling and descrambling data.

Implementing known scrambling relationship among multiple serial links

A method and circuit for implementing serial link training sequences, and a design structure on which the subject circuit resides are provided. A transmitter device transmits a training sequence (TS) pattern; then the transmitter device transmits random data for a predefined time duration. The steps of transmitting the TS-pattern, then transmitting the random data for the fixed time duration are repeated. A receiver device detecting a plurality of the TS-patterns separated by the predefined time interval of random data, performs receiver initialization steps. The receiver device performs a plurality of receiver initialization steps including, for example, acquiring byte lock, and a link width determination.

Implementing serial link training patterns separated by random data for training a serial link in an interconnect system

A method, and apparatus are provided for implementing processor bus speculative data completion in a computer system. A memory controller in the computer system sends uncorrected data from a memory to a processor bus. The memory controller also applies the uncorrected data to error correcting code (ECC) checking and correcting circuit. When a single bit error (SBE) is detected, corrected data is sent to the processor bus a predefined number of cycles after the uncorrected data.

Apparatus for implementing processor bus speculative data completion

A technique for accessing a memory array includes receiving, from multiple requesters, memory access requests directed to a single port of the memory array. The memory access requests associated with each of the multiple requesters are serviced, based on a priority assigned to each of the multiple requesters, while maintaining a fixed timing for the memory access requests.

Scalable interface for a memory array

In a shared memory architecture, early coherency indication is used to notify a communications interface, prior to the data for a memory request is returned, and prior to updating a coherency directory in response to the memory request, that the return data can be used by the communications interface when it is received thereby from a source of the return data. By doing so, the communications interface can often begin forwarding the return data over its associated communication link with little or no latency once the data is retrieved from its source. In addition, the communications interface is often no longer required to wait for updating of the coherency directory to complete prior to forwarding the return data over the communication link. As such, the overall latency for handling the memory request is typically reduced.

Early coherency indication for return data in shared memory architecture

Uncontested priority is provided to out-of-order data transfers over in-order data transfers on a data bus shared by a plurality of memory requesters. By always granting priority to out-of-order transfers such as deferred read data transfers over in-order transfers such as write and/or cache-to-cache data transfers, it is assured that no newer command or transaction ever negatively affects the latency of an older command or transaction.

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Rochester, MN, United States of America

Wayne Melvin Barrett