Advanced Micro Devices Corporation

Ati Technologies Ulc

Mangesh P Nijasure

Todd Martin

Michael Mantor

Vineet Goel

Randy Wayne Ramsey

Jason David Carroll

Saad Arrabi

Nishank Pathak

Tad Robert Litwiller

Anirudh Rajendra Acharya

Alexander Fuad Ashkar

Swapnil Pradipkumar Sakharshete

Brian A Buchner

Brian D Emberling

Laurent Lefebvre

Manu Rastogi

Ashkan Hosseinzadeh Namin

Vishrut Vaibhav

Rakan Z Khraisha

Brian J Favela

Louis Regniere

Methods and systems are disclosed for inline suspension of an accelerated processing unit (APU). Techniques include receiving a packet, including a mode of operation and commands to be executed by the APU; suspending execution of commands received in previous packets when the mode of operation is a suspension initiation mode; and executing, by the APU, the commands in the received packet. The execution of the suspended commands is restored when the mode of operation in a subsequently received packet is a suspension conclusion mode.

Inline suspension of an accelerated processing unit

Improvements to graphics processing pipelines are disclosed. More specifically, the vertex shader stage, which performs vertex transformations, and the hull or geometry shader stages, are combined. If tessellation is disabled and geometry shading is enabled, then the graphics processing pipeline includes a combined vertex and graphics shader stage. If tessellation is enabled, then the graphics processing pipeline includes a combined vertex and hull shader stage. If tessellation and geometry shading are both disabled, then the graphics processing pipeline does not use a combined shader stage. The combined shader stages improve efficiency by reducing the number of executing instances of shader programs and associated resources reserved.

Combined world-space pipeline shader stages

A method of deferred vertex attribute shading includes computing, at a graphics processing pipeline of a graphics processing unit (GPU), a plurality of vertex attributes for vertices of each primitive of a set of primitives. The plurality of vertex attributes to be computed includes a vertex position attribute and at least a first non-position attribute for each primitive. One or more primitives of the set of primitives that do not contribute to a rendered image are discarded based upon the vertex position attribute for vertices of the set of primitives. A set of surviving primitives is generated based on the culling and deferred attribute shading is performed for at least a second non-position attribute for vertices of the set of surviving primitives.

Optimizing primitive shaders

A graphics pipeline reduces the number of tessellation factors written to and read from a graphics memory. A hull shader stage of the graphics pipeline detects whether at least a threshold percentage of the tessellation factors for a thread group of patches are the same and, in some embodiments, whether at least the threshold percentage of the tessellation factors for a thread group of patches have a same value that either indicates that the plurality of patches are to be culled or that the plurality of patches are to be passed to a tessellator stage of the graphics pipeline. In response to detecting that at least the threshold percentage of the tessellation factors for the thread group are the same (or, additionally, that at least the threshold percentage of the tessellation factors have a value that either indicates that the plurality of patches are to be culled or that the plurality of patches are to be passed to a tessellator stage of the graphics pipeline), the hull shader stage bypasses writing at least a subset of the tessellation factors for the thread group of patches to the graphics memory, thus reducing bandwidth and increasing efficiency of the graphics pipeline.

Reduced bandwidth tessellation factors

A graphics pipeline includes a tessellator stage having a sub-patch distributor and a plurality of tessellators. The sub-patch distributor divides an input patch into a plurality of sub-primitive groups, with the primitive group limit governing the maximum permissible size for a given group of sub-primitives to be assigned to a tessellator. The sub-patch distributor recursively identifies a plurality of regions of the input patch, with the size and number of primitives of each region based on the specified primitive group limit. The sub-patch distributor assigns different regions to different sub-patch groups and distributes the sub-patch groups among the plurality of tessellators.

Tessellator sub-patch distribution based on group limits

The address of the draw or dispatch packet responsible for creating an exception is tied to a shader/wavefront back to the draw command from which it originated. In various embodiments, a method of operating a graphics pipeline and exception handling includes receiving, at a command processor of a graphics processing unit (GPU), an exception signal indicating an occurrence of a pipeline exception at a shader stage of a graphics pipeline. The shader stage generates an exception signal in response to a pipeline exception and transmits the exception signal to the command processor. The command processor determines, based on the exception signal, an address of a command packet responsible for the occurrence of the pipeline exception.

Exception handler for sampling draw dispatch identifiers

Improvements in the graphics processing pipeline are disclosed. More specifically, a new primitive shader stage performs tasks of the vertex shader stage or a domain shader stage if tessellation is enabled, a geometry shader if enabled, and a fixed function primitive assembler. The primitive shader stage is compiled by a driver from user-provided vertex or domain shader code, geometry shader code, and from code that performs functions of the primitive assembler. Moving tasks of the fixed function primitive assembler to a primitive shader that executes in programmable hardware provides many benefits, such as removal of a fixed function crossbar, removal of dedicated parameter and position buffers that are unusable in general compute mode, and other benefits.

Primitive shader

A graphics processing unit (GPU) adjusts a frequency of clock based on identifying a program thread executing at the processing unit, wherein the program thread is detected based on a workload to be executed. By adjusting the clock frequency based on the identified program thread, the processing unit adapts to different processing demands of different program threads. Further, by identifying the program thread based on workload, the processing unit adapts the clock frequency based on processing demands, thereby conserving processing resources.

Workload-based clock adjustment at a processing unit

A graphics processing unit (GPU) includes a packet management component that automatically aggregates data from input packets. In response to determining that a received first input packet does not indicate a send condition, and in response to determining that a generated output packet would be smaller than an output size threshold, the packet management component aggregates data corresponding to the first input packet with data corresponding to a second input packet stored at a packet buffer. In response to determining that a received third input packet indicates a send condition, the packet management component sends the aggregated data to a compute unit in an output packet and performs an operation indicated by the send condition.

GPU packet aggregation system

Improvements in the graphics processing pipeline that allow multiple pipelines to cooperate to render a single frame are disclosed. Two approaches are provided. In a first approach, world-space pipelines for the different graphics processing pipelines process all work for draw calls received from a central processing unit (CPU). In a second approach, the world-space pipelines divide up the work. Work that is divided is synchronized and redistributed at various points in the world-space pipeline. In either approach, the triangles output by the world-space pipelines are distributed to the screen-space pipelines based on the portions of the render surface overlapped by the triangles. Triangles are rendered by screen-space pipelines associated with the render surface portions overlapped by those triangles.

Split frame rendering

Techniques for removing reset indices from, and identifying primitives in, an index stream that defines a set of primitives to be rendered, are disclosed. The index stream may be specified by an application program executing on the central processing unit. The technique involves classifying the primitive topology for the index stream as either requiring an offset-based technique or requiring a non-offset-based technique. This classification is done by determining whether, according to the primitive topology, each subsequent index can form a primitive with prior indices (e.g., line strip, triangle strip). If each subsequent index can form a primitive with prior indices, then the technique used is the non-offset-based technique. If each subsequent index does not form a primitive with prior indices, but instead at least two indices are required to form a new primitive (e.g., line list, triangle list), then the technique used is the offset-based technique.

Identifying primitives in input index stream

Processing of non-real-time and real-time workloads is performed using discrete pipelines. A first pipeline includes a first shader and one or more fixed function hardware blocks. A second pipeline includes a second shader that is configured to emulate the at least one fixed function hardware block. First and second memory elements store first state information for the first pipeline and second state information for the second pipeline, respectively. A non-real-time workload executing in the first pipeline is preempted at a primitive boundary in response to a real-time workload being dispatched for execution in the second pipeline. The first memory element retains the first state information in response to preemption of the non-real-time workload. The first pipeline is configured to resume processing the subsequent primitive on the basis of the first state information stored in the first memory element.

Growing community of inventors

Orlando, FL, United States of America

Mangesh P Nijasure