Nvidia Corporation

Other

James Van Zoeren

Guillermo Juan Rozas

Paul S Serris

Alexander Klaiber

Magnus Ekman

Darrell D Boggs

Ross Segelken

Hens Vanderschoot

Brad Hoyt

Sridharan Ramakrishnan

David A Dunn

Bruce Holmer

Parag Gupta

Brian Holscher

Aravindh Baktha

Bharath Krishnan

Embodiments related to selecting a runahead poison policy from a plurality of runahead poison policies during microprocessor operation are provided. The example method includes causing the microprocessor to enter runahead upon detection of a runahead event and implementing a first runahead poison policy selected from a plurality of runahead poison policies operative to manage runahead poison injection during runahead. The example method also includes during microprocessor operation, selecting a second runahead poison policy operative to manage runahead poison injection differently from the first runahead poison policy.

Selective poisoning of data during runahead

A method for detecting an instruction ordering violation in a CPU. The method includes receiving a reordered stream of instructions and detecting whether an ordering violation has occurred by using virtual addresses. The method further includes transferring results of the reordered stream of instructions from a load store buffer into a cache and detecting whether an ordering violation has occurred by using physical addresses. Subsequently, a recovery is initiated upon detection of an ordering violation.

Virtual address based memory reordering

Embodiments related to managing lazy runahead operations at a microprocessor are disclosed. For example, an embodiment of a method for operating a microprocessor described herein includes identifying a primary condition that triggers an unresolved state of the microprocessor. The example method also includes identifying a forcing condition that compels resolution of the unresolved state. The example method also includes, in response to identification of the forcing condition, causing the microprocessor to enter a runahead mode.

Lazy runahead operation for a microprocessor

Various embodiments of microprocessors and methods of operating a microprocessor during runahead operation are disclosed herein. One example method of operating a microprocessor includes identifying a runahead-triggering event associated with a runahead-triggering instruction and, responsive to identification of the runahead-triggering event, entering runahead operation and inserting the runahead-triggering instruction along with one or more additional instructions in a queue. The example method also includes resuming non-runahead operation of the microprocessor in response to resolution of the runahead-triggering event and re-dispatching the runahead-triggering instruction along with the one or more additional instructions from the queue to the execution logic.

Queued instruction re-dispatch after runahead

Embodiments related to managing potentially invalid results generated/obtained by a microprocessor during runahead are provided. In one example, a method for operating a microprocessor includes causing the microprocessor to enter runahead upon detection of a runahead event. The example method also includes, during runahead, determining that an operation associated with an instruction referencing a storage location would produce a potentially invalid result based on a value of an architectural poison bit associated with the storage location and performing a different operation in response.

Managing potentially invalid results during runahead

In a processor, a method for speculative permission acquisition for access to a shared memory. The method includes receiving a store from a processor core to modify a shared cache line, and in response to receiving the store, marking the cache line as speculative. The cache line is then modified in accordance with the store. Upon receiving a modification permission, the modified cache line is subsequently committed.

Speculative permission acquisition for shared memory

A processing bypass register file system and method are disclosed. In one embodiment a processing bypass register file includes a rotating head pointer, and a plurality of write ports, storage cells and read ports. The write ports receive processing result information. The head pointer identifies which entries are written by the write ports. The plurality of cells store the processing result information. The read ports forward results to the processing data path, and to an architectural register file for retirement.

Processing bypass register file system and method

Systems and methods for reordering processor instructions. In accordance with a first embodiment of the present invention, a microprocessor comprises circuitry to process an instruction extension, wherein the instruction extension is transparent to the programming model of the microprocessor. The instruction extension may comprise a field for indicating an offset from a memory structure pointer. The microprocessor includes circuitry for adding the offset to the memory structure pointer to indicate a specific element of the memory structure. The specific element of the memory structure comprises address information corresponding to speculative data.

Growing community of inventors

Albuquerque, NM, United States of America

James Van Zoeren