International Business Machines Corporation

James A Mossman

Michael Raymond Trombley

Steven Kenneth Jenkins

James Johnson Allen, Jr

Robert Brett Tremaine

Daniel Mark Dreps

Kevin Charles Gower

Kyu-hyoun Kim

Michael Anthony Sorna

Michael Kevin Kerr

William M Zevin

David William Mann

Robert Brian Likovich, Jr

Theodore Paul Haggis

Tiffany Tamaddoni-Jahromi

A method for handling speculative access requests for a storage device in a computer system is provided. The method includes the steps of providing a speculative access threshold corresponding to a selected percentage of the total number of accesses to be speculatively issued, and intermixing demand accesses and speculative accesses in accordance with the speculative access threshold. In another embodiment, a method for reducing data access latency experienced by a user in a computer network is provided. The method includes the steps of providing a web page comprising a link to a data file stored on a database connected to the computer network, selecting a speculative access threshold corresponding to a selected percentage of data accesses which are to be speculatively provided to the user, and speculatively providing the data file in accordance with the speculative access threshold.

System and method for handling data access

A method and apparatus for determining correct timing for receiving, in a host in a memory system, of a normal toggle transmitted by an addressed memory chip on a bidirectional data strobe. An offset in the data strobe is established, either by commanding the addressed memory chip, in a training period, to drive the data strobe to a known state, except during transmission of a normal toggle, or by providing a voltage offset between a true and a complement phase in the data strobe, or by providing a circuit bias in a differential receiver on the host the receives the data strobe. A series of read commands are transmitted by the host to the addressed memory chip, which responds by transmitting the normal toggle. Timing of reception of the normal toggle as received by the host chip is adjusted until the normal toggle is correctly received.

Strobe offset in bidirectional memory strobe configurations

A bus system that includes a plurality of signal driving devices coupled to a common signal bus, a bus controlled circuit coupled to the common signal bus, and a compare circuit. The plurality of signal driving devices include a first signal driving device and a second signal driving device. The bus controller includes delay compensation circuitry with a configurable delay for each of the signal driving devices. The delay compensation circuitry has a current delay chain configuration associated with the first signal driving device. The compare circuit is configured to compare a first configurable delay associated with a first signal driving device to a second configurable delay associated with a second signal driving device of the plurality of signal driving devices, and for generating an output responsive to the comparing that indicates if the current delay chain configuration can be used by the second signal driving device.

Opportunistic bus access latency

A design structure embodied in a machine readable storage medium for designing, manufacturing, and/or testing a design is provided. The design structure generally includes a processor memory system, which may include a processor and a memory controller in communication with the processor through a bus. The memory controller may include a delay circuit to receive an early read indicator corresponding to read data from a memory, the delay circuit to delay the early read indicator in accordance with a pre-determined delay such that the early read indicator is passed to the bus in advance of the read data, and a delay adjustment circuit to dynamically adjust the pre-determined delay associated with the delay circuit responsive to a change in operational speed of the processor or the bus.

Structure for reducing latency associated with read operations in a memory system

A design structure embodied in a machine readable storage medium for designing, manufacturing, and/or testing a design is provided. The design structure generally includes a computer system that includes a CPU, a storage device, circuitry for providing a speculative access threshold corresponding to a selected percentage of the total number of accesses to the storage device that can be speculatively issued, and circuitry for intermixing demand accesses and speculative accesses in accordance with the speculative access threshold.

Structure for handling data access

A system and method for handling speculative read requests for a memory controller in a computer system are provided. In one example, a method includes the steps of providing a speculative read threshold corresponding to a selected percentage of the total number of reads that can be speculatively issued, and intermixing demand reads and speculative reads in accordance with the speculative read threshold. In another example, a computer system includes a CPU, a memory controller, memory, a bus connecting the CPU, memory controller and memory, circuitry for providing a speculative read threshold corresponding to a selected percentage of the total number of reads that can be speculatively issued, and circuitry for intermixing demand reads and speculative reads in accordance with the speculative read threshold. In another example, a method includes the steps of providing a speculative dispatch time threshold corresponding to a selected percentage of a period of time required to search a cache of the computer system, and intermixing demand reads and speculative reads in accordance with the speculative dispatch time threshold.

System and method for handling data requests

A design structure embodied in a machine readable storage medium for designing, manufacturing, and/or testing a design is provided. The design structure generally includes a computer system that includes a CPU, a memory controller, memory, a bus connecting the CPU, memory controller and memory, circuitry for providing a speculative read threshold corresponding to a selected percentage of the total number of reads that can be speculatively issued, and circuitry for intermixing demand reads and speculative reads in accordance with the speculative read threshold.

Structure for handling data requests

Methods and system for reducing latency associated with a read operation in a processor memory system are provided. In one implementation, the method includes receiving an early indicator corresponding to read data from a memory, delaying the early indicator in accordance with a pre-determined delay such that the early read indicator is passed to a bus in advance of the read data; and dynamically adjusting the pre-determined delay using an adjustment delay circuit, the pre-determined delay being adjusted responsive to a change in operational speed of the bus or change in operational speed of a processor coupled to the bus.

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Raleigh, NC, United States of America

James A Mossman