International Business Machines Corporation

Christopher Michael Abernathy

Mary Douglass Brown

Dung Q Nguyen

Ronald P Hall

Hung Qui Le

David James Shippy

Jonathan James DeMent

Albert James Van Norstrand, Jr

Todd Alan Venton

Kurt Alan Feiste

James Allan Kahle

Susan Elizabeth Eisen

William Elton Burky

Gilles Gervais

Robert Alan Philhower

Sundeep Chadha

Timothy Hume Heil

Jens Leenstra

Nicolas Maeding

Benjamin W Stolt

Jeffrey Powers Bradford

Rolf Hilgendork

Lydia Mai Do

Joel Abraham Silberman

Markus Kaltenbach

Maarten Jakob Boersma

David Scott Ray

Robert Allen Cordes

James Wilson Bishop

John Barry Griswell, Jr

Michael Lance Karm

Rolf B Hilgendorf

Albert Thomas Williams

Ulrike Schmidt

Scott Raymond Cottier

James Albert Van Norstrand, Jr

A processor includes a first level register file, second level register file, and register file mapper. The first and second level register files are comprised of physical registers, with the first level register file more efficiently accessed relative to the second level register file. The register file mapper is coupled with the first and second level register files. The register file mapper comprises a mapping structure and register file mapper controller. The mapping structure hosts mappings between logical registers and physical registers of the first level register file. The register file mapper controller determines whether to map a destination logical register of an instruction to a physical register in the first level register file. The register file mapper controller also determines, based on metadata associated with the instruction, whether to write data associated with the destination logical register to one of the physical registers of the second level register file.

Processor for avoiding reduced performance using instruction metadata to determine not to maintain a mapping of a logical register to a physical register in a first level register file

A system and process for managing thread execution includes providing two data register sets coupled to a processor and using, by the processor, the two register sets as first-level registers for thread execution. A portion of main memory or cache memory is assigned as second-level registers where the second-level registers serve as registers of at least one of the two data register sets for executing the threads. Data for the threads may be moved between the first-level registers and second-level registers for different modes of thread processing.

Thread transition management

A system and process for managing thread transitions includes providing two data register sets coupled to a processor and using, by the processor, the two register sets as first-level registers for thread execution. A determination is made whether a quantity of the first-level registers needed to execute one or more threads exceeds a quantity of the first-level registers of the two data register sets. Responsive to determining that the quantity of the first-level registers needed to execute the one or more threads exceeds the quantity of the first-level registers of the two data register sets, a portion of main memory or cache memory is assigned as second-level registers where the second-level registers serve as registers of at least one of the two data register sets for executing the one or more threads.

A system and process for managing thread transitions includes determining that a transition is to be made regarding the relative use of two data register sets where the two data register sets are used by a processor as first-level registers for thread execution. Based on the transition determination, a determination is made whether to move thread data in at least one of the first-level registers to second-level registers. Responsive to determining to move the thread data, a portion of main memory or cache memory is assigned as the second-level registers where the second-level registers serve as registers of at least one of the two data register sets for executing a thread. The thread data from the at least one first-level register is moved to the second-level registers based on the move determination.

A register file bypass controller in communication with a set of one or more bypass registers, the register file bypass controller configured to receive a register file bypass request; determine whether to grant the register file bypass request; determine whether data identified by the register file bypass request is present in the set of one or more bypass registers in response to determining to grant the register file bypass request; determine a selected bypass register in the set of one or more bypass registers in response to determining the data identified by the register file bypass request is not present in the set of one or more bypass registers; determine to store the data identified by the register file bypass request in the selected bypass register; and notify an execution unit to cancel instruction execution associated with the data identified by the register file bypass request.

Bypassing a higher level register file in a processor having a multi-level register file and a set of bypass registers

Various systems, processes, products, and techniques may be used to manage thread transitions. In particular implementations, a system and process for managing thread transitions may include the ability to determine that a transition is to be made regarding the relative use of two data register sets and determine, based on the transition determination, whether to move thread data in at least one of the data register sets to second-level registers. The system and process may also include the ability to move the thread data from at least one data register set to second-level registers based on the move determination.

A method detects active power dissipation in an integrated circuit. The method includes receiving a hardware design for the integrated circuit having one or more clock domains, wherein the hardware design comprises a local clock buffer for a clock domain, wherein the local clock buffer is configured to receive a clock signal and an actuation signal. The method includes adding instrumentation logic to the design for the clock domain, wherein the instrumentation logic is configured to compare a first value of the actuation signal determined at a beginning point of a test period to a second value of the actuation signal determined at a time when the clock domain is in an idle condition. The method includes detecting the clock domain includes unintended active power dissipation, in response to the first value of the actuation signal not being equal to the second value of the actuation signal.

Active power dissipation detection based on erroneus clock gating equations

A processor includes an execution unit, a first level register file, a second level register file, a plurality of storage locations and a register file bypass controller. The first and second level register files are comprised of physical registers, with the first level register file more efficiently accessed relative to the second level register file. The register file bypass controller is coupled with the execution unit and second level register file. The register file bypass controller determines whether an instruction indicates a logical register is unmapped from a physical register in the first level register file. The register file controller also loads data into one of the storage locations and selects one of the storage locations as input to the execution unit, without mapping the logical register to one of the physical registers in the first level register file.

Efficient usage of a multi-level register file utilizing a register file bypass

Instructions are tracked in a processor. A completion unit in the processor receives an instruction group to add to a table to form a received instruction group. In response to receiving the received instruction group, the completion unit determines whether an entry is present that contains a previously stored instruction group in a first location and has space for storing the received instruction group. In response to the entry being present, the completion unit stores the received instruction group in a second location in the entry to form a stored instruction group.

Instruction tracking system for processors

A processor includes an instruction fetch unit, an issue queue coupled to the instruction fetch unit, an execution unit coupled to the issue queue, and a multi-level register file including a first level register file having lower access latency and a second level register file having higher access latency. Each of the first and second level register files includes a plurality of physical registers for holding operands that is concurrently shared by a plurality of threads. The processor further includes a mapper that, at dispatch of an instruction specifying a source logical register from the instruction fetch unit to the issue queue, initiates a swap of a first operand associated with the source logical register that is in the second level register file with a second operand held in the first level register file. The issue queue, following the swap, issues the instruction to the execution unit for execution.

Multi-level register file supporting multiple threads

A processor includes an instruction sequencing unit, execution unit, and multi-level register file including a first level register file having a lower access latency and a second level register file having a higher access latency. Responsive to the processor processing a second instruction in a transactional code section to obtain as an execution result a second register value of the logical register, the mapper moves a first register value of the logical register to the second level register file, places the second register value in the first level register file, marks the second register value as speculative, and replaces a first mapping for the logical register with a second mapping. Responsive to unsuccessful termination of the transactional code section, the mapper designates the second register value in the first level register file as invalid so that the first register value in the second level register file becomes the working value.

Register file supporting transactional processing

A method and apparatus for tracking instructions in a processor. A completion unit in the processor receives an instruction group to add to a table to form a received instruction group. In response to receiving the received instruction group, the completion unit determines whether an entry is present that contains a previously stored instruction group in a first location and has space for storing the received instruction group. In response to the entry being present, the completion unit stores the received instruction group in a second location in the entry to form a stored instruction group.

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Austin, TX, United States of America

Christopher Michael Abernathy