Nvidia Corporation

Nividia Corporation

Mark J French

Steven E Molnar

Adam Clark Weitkemper

Cass Watson Everitt

Phillip Craig Keslin

Daniel P Wilde

David L Anderson

John Stephen Montrym

John M Danskin

Bengt-Olaf Schneider

George R Lynch

Robert J Stoll

Jerome Francis Duluk, Jr

Henry Packard Moreton

John Erik Lindholm

Emmett Michael Kilgariff

John H Edmondson

Douglas A Voorhies

Justin S Legakis

Roger L Allen

Gary M Tarolli

Walter Robert Steiner

Jonathan J Dunaisky

Lukito Muliadi

Weizhong Xu

Adam Clark Wietkemper

Gregory J Stiehl

One embodiment of the present invention sets forth an architecture for advancing the Z-test operation prior to pixel shading whenever possible. The current rendering state, as maintained by the setup engine, determines whether advancing the Z-test function above the shader engine for 'early' Z-testing is possible or whether the Z-test function should be deferred until after shading operations for 'late' Z-testing. Data is dynamically routed to each processing engine in the pipeline, so that the appropriate data flow for either early Z or late Z is dynamically constructed, as determined by the current rendering state. The same functional units are utilized in both early Z and late Z configurations.

Optimizing a graphics rendering pipeline using early Z-mode

A parallel array architecture for a graphics processor includes a multithreaded core array including a plurality of processing clusters, each processing cluster including at least one processing core operable to execute a pixel shader program that generates pixel data from coverage data; a rasterizer configured to generate coverage data for each of a plurality of pixels; and pixel distribution logic configured to deliver the coverage data from the rasterizer to one of the processing clusters in the multithreaded core array. A crossbar coupled to each of the processing clusters is configured to deliver pixel data from the processing clusters to a frame buffer having a plurality of partitions.

Parallel array architecture for a graphics processor

The current invention involves new systems and methods for computing per-sample post-z test coverage when the memory is organized in multiple partitions that may not match the number of shaders. Shaded pixels output by the shaders can be processed by one of several z raster operations units. The shading processing capability can be configured independent of the number of memory partitions and number of z raster operations units. The current invention also involves new systems and method for using different z test modes with multiple render targets with a single or multiple memory partitions. Rendering performance may be improved by using an early z testing mode is used to eliminate non-visible samples prior to shading.

Late Z testing for multiple render targets

One embodiment of the present invention sets forth a technique for improving graphics rendering efficiency by processing pixels in a compressed format whenever possible within a multi-sampling graphics pipeline. Each geometric primitive is rasterized into fragments, corresponding to screen space pixels covered at least partially by the geometric primitive. Fragment coverage represents the pixel area covered by the geometric primitive and determines the weighted contribution of a fragment color to the corresponding screen space pixel. Samples associated with a given fragment are called sibling samples and have the same color value. The property of sibling samples having the same color value is exploited to compress and process multiple samples, thereby reducing the size of the associated logic and the amount of data written to and read from the frame buffer.

Color-compression using automatic reduction of multi-sampled pixels

Z-test result reconciliation with multiple partitions

Early Z testing for multiple render targets

One embodiment of the present invention sets forth a graphics pipeline architecture for optimizing graphics rendering efficiency by advancing the Z-test operation prior to shading operations whenever possible, as determined by an upstream pipeline configuration unit. Each processing engine within the graphics pipeline maintains independent state for both early Z-mode and late Z-mode operations and also may maintain state common to both modes. The processing engines receive work transactions that include a Z-mode flag indicating whether the work transaction should be processed in late Z-mode or early Z-mode. The Z-mode flag is also used to dynamically route any resulting outbound data, so that the appropriate data flow for either early Z or late Z processing is dynamically constructed for each work transaction. The shader engine is advantageously relieved of unnecessary work whenever possible by discarding occluded samples whose z-values are not altered by shading operations before they enter the shader engine.

Graphics rendering pipeline that supports early-Z and late-Z virtual machines

A method and system for improving data coherency in a parallel rendering system is disclosed. Specifically, one embodiment of the present invention sets forth a method, which includes the steps of receiving a common input stream, tracking a periodic event associated with the common input stream, generating a plurality of fragment streams from the common input stream, inserting a marker based on an occurrence of the periodic event in a first fragment stream in the multiple fragment streams, and utilizing the marker to influence the processing of the first fragment stream so that a plurality of raster operation (ROP) request streams maintains substantially the same coherence as the common input stream. Each fragment stream is independently processed and corresponds to one of the ROP request streams.

Method and system for improving data coherency in a parallel rendering system

A method of performing a blit operation in a parallel processing system includes dividing a blit operation into batches of pixels, performing reads of pixels associated with a first batch in any order, confirming that all reads of pixels associated with the first batch are completed, and performing writes of pixels associated with the first batch in any order. The pixels of the first batch and pixels of additional batches are applied to parallel processors, where the parallel processors include a corral defined by entry points and exit points distributed across the parallel processors.

Apparatus and method for performing blit operations across parallel processors

Methods and systems for reusing memory addresses in a graphics system are disclosed, so that instances of address translation hardware can be reduced. One embodiment of the present invention sets forth a method, which includes mapping a footprint on a display screen to a group of contiguous physical memory locations in a memory system, determining an anchor physical memory address from a first transaction associated with the footprint, wherein the anchor physical memory address corresponds to an anchor in the group of contiguous physical memory locations, determining a second transaction that is also associated with the footprint, determining a set of least significant bits (LSBs) associated with the second transaction, and combining the anchor physical memory address with the set of LSBs associated with the second transaction to generate a second physical memory address for the second transaction, thereby avoiding a second full address translation.

Methods and systems for reusing memory addresses in a graphics system

Methods and systems for reusing memory addresses in a graphics system are disclosed, so that instances of address translation hardware can be reduced. One embodiment of the present invention sets forth a method, which includes mapping a footprint in screen space to a group of contiguous physical memory locations in a memory system, determining a first physical memory address for a first transaction associated with the footprint, wherein the first physical memory address is within the group of contiguous physical memory locations, determining a second transaction that is also associated with the footprint, determining a set of least significant bits associated with the second transaction, and combining a portion of the first physical memory address with the set of least significant bits associated with the second transaction to generate a second physical memory address for the second transaction, thereby avoiding a second full address translation.

A synchronization mechanism is used to synchronize events across multiple execution pipelines that process transaction streams. A common set of state configuration is included in each transaction stream to control processing of data that is distributed between the different transaction streams. Portions of the state configuration correspond to portions of the data. Execution of the transaction streams is synchronized to ensure that each portion of the data is processed using the state configuration that corresponds to that portion of the data. The synchronization mechanism may be used for multiple synchronizations and when the synchronization signals are pipelined to meet chip-level timing requirements.

Latency tolerant pipeline synchronization

A technique for handling floating-point special values, e.g., Infinity, NaN, &#x2212;Zero, and denorms, during blend operations is provided so that blend operations on fragment color values that contain special values can be performed in compliance with special value handling rules. In particular, the presence of special values is detected or the potential presence of special values is detected. This information is used to qualify when blend optimizations may be performed, so that floating point blend operations can remain conformant to special value handling rules.

Blend optimizations that are conformant to floating-point rules

The number of crossbars in a graphics processing unit is reduced by assigning each of a plurality of pixels to one of a plurality of pixel shaders based at least in part on a location of each of the plurality of pixels within an image area, generating an attribute value for each of the plurality of pixels using the plurality of pixel shaders, mapping the attribute value of each of the plurality of pixels to one of a plurality of memory partitions, and storing the attribute values in the memory partitions according to the mapping. The attribute value generated by a particular one of the pixel shaders is mapped to the same one of the plurality of memory partitions.

Connecting multiple pixel shaders to a frame buffer without a crossbar

A high-performance crossbar for a pipeline is disclosed. In particular, one embodiment of the crossbar receives multimedia data at a first throughput from a source operating in a first pipeline stage. The received data are stored in at least one input buffer corresponding to the source in the crossbar. The crossbar also causes the multimedia data from the input buffer to be routed to at least one output buffer at a second throughput. The output buffer corresponds to a destination operating in a second pipeline stage. Then the crossbar causes the multimedia data from the output buffer to be routed to the destination at the first throughput.

Growing community of inventors

Raleigh, NC, United States of America

Mark J French