Nvidia Corporation

Cynthia Ann Edgeworth Allison

Dale L Kirkland

Ziyad Sami Hakura

Emmett Michael Kilgariff

Karim Abdalla

Walter Robert Steiner

Johnny S Rhoades

Karl M Wurstner

Steven E Molnar

Sean Jeffrey Treichler

Jeffrey A Bolz

Rouslan Lyubomirov Dimitrov

Timothy John Purcell

Andrei Khodakovsky

Pierre Souillot

Gernot Schaufler

Joseph Cavanaugh

One embodiment of the present invention includes a graphics subsystem that includes a tiling unit, a crossbar unit, and a screen-space pipeline. The crossbar unit is configured to transmit primitives interleaved with state change commands to the tiling unit. The tiling unit is configured to record an initial state associated with the primitives and to transmit to the screen-space pipeline one or more primitives in the primitives that overlap a first cache tile. The tiling unit is further configured to transmit the initial state to the screen-space pipeline and to transmit to the screen-space pipeline one or more primitives in the primitives that overlap a second cache tile. The tiling unit includes a state filter block configured to determine that a first state change in the state change commands is followed by a second state change, without an intervening primitive, and to forego transmitting the first state change in response.

State handling in a tiled architecture

One embodiment of the present invention sets forth a technique for managing graphics processing resources in a tile-based architecture. The technique includes storing a release packet associated with a graphics processing resource in a buffer and initiating a replay of graphics primitives stored in the buffer and associated with the graphics processing resource. The technique further includes, for each tile included in a plurality of tiles and processed during the replay, reading the release packet and determining whether the tile is a last tile processed during the replay. The technique further includes determining not to transmit the release packet to a screen-space pipeline and continuing to read graphics data stored in the buffer if the tile is not the last tile to be processed during the replay, or transmitting the release packet to the screen-space pipeline if the tile is the last tile to be processed during the replay.

Techniques for managing graphics processing resources in a tile-based architecture

One embodiment of the present invention sets forth a graphics subsystem configured to implement distributed cache tiling. The graphics subsystem includes one or more world-space pipelines, one or more screen-space pipelines, one or more tiling units, and a crossbar unit. Each world-space pipeline is implemented in a different processing entity and is coupled to a different tiling unit. Each screen-space pipeline is implemented in a different processing entity and is coupled to the crossbar unit. The tiling units are configured to receive primitives from the world-space pipelines, generate cache tile batches based on the primitives, and transmit the primitives to the screen-space pipelines. One advantage of the disclosed approach is that primitives are processed in application-programming-interface order in a highly parallel tiling architecture. Another advantage is that primitives are processed in cache tile order, which reduces memory bandwidth consumption and improves cache memory utilization.

Distributed tiled caching

One embodiment of the present invention includes a technique for processing graphics primitives in a tile-based architecture. The technique includes storing, in a buffer, a first plurality of graphics primitives and a first plurality of state bundles received from the world-space pipeline. The technique further includes determining, based on a first condition, that the first plurality of graphics primitives should be replayed from the buffer, and, in response, replaying the first plurality of graphics primitives against a first tile included in a first plurality of tiles. Replaying the first plurality of graphics primitives includes comparing each graphics primitive against the first tile to determine whether the graphics primitive intersects the first tile, determining that one or more graphics primitives intersects the first tile, and transmitting the one or more graphics primitives and one or more associated state bundles to a screen-space pipeline for processing.

Heuristics for improving performance in a tile based architecture

One embodiment of the present invention sets forth a technique for managing buffer table entries in a tile-based architecture. The technique includes binding a plurality of shader registers to a buffer table entry. The technique further includes processing at least one tile by reading a buffer table index stored in the shader register to access the buffer table entry, reading a buffer address stored in the buffer table entry, accessing data associated with the buffer address, and unbinding the shader register from the buffer table entry. The technique further includes determining that none of the shader registers is still bound to the buffer table entry and, in response, causing a release packet to be inserted into an instruction stream. The technique further includes determining that a last tile has been processed and, in response, transmitting the release packet to cause the buffer table entry to be released.

One embodiment of the present invention includes a technique for processing graphics primitives in a tile-based architecture. The technique includes storing, in a buffer, a first plurality of graphics primitives and a first plurality of state bundles received from a world-space pipeline, and transmitting the first plurality of graphics primitives to a screen-space pipeline for processing while a tiling function is enabled. The technique further includes storing, in the buffer, a second plurality of graphics primitives and a second plurality of state bundles received from the world-space pipeline. The technique further includes determining, based on a first condition, that the tiling function should be disabled and that the second plurality of graphics primitives should be flushed from the buffer, and transmitting the second plurality of graphics primitives to the screen-space pipeline for processing while the tiling function is disabled.

Heuristics for improving performance in a tile-based architecture

One embodiment of the present invention sets forth a graphics subsystem configured to implement distributed tiled caching. The graphics subsystem includes one or more world-space pipelines, one or more screen-space pipelines, one or more tiling units, and a crossbar unit. Each world-space pipeline is implemented in a different processing entity and is coupled to a different tiling unit. Each screen-space pipeline is implemented in a different processing entity and is coupled to the crossbar unit. The tiling units are configured to receive primitives from the world-space pipelines, generate cache tile batches based on the primitives, and transmit the primitives to the screen-space pipelines. One advantage of the disclosed approach is that primitives are processed in application-programming-interface order in a highly parallel tiling architecture. Another advantage is that primitives are processed in cache tile order, which reduces memory bandwidth consumption and improves cache memory utilization.

One embodiment of the present invention sets forth a technique for managing buffer entries in a tile-based architecture. The technique includes receiving a first plurality of graphics primitives and a first buffer address at which attributes associated with the first plurality of graphics primitives are stored. The technique further includes, for each tile included in a plurality of tiles, transmitting the first plurality of graphics primitives and the first buffer address to a screen space pipeline and receiving an acknowledgement from the screen space pipeline indicating that processing the first plurality of graphics primitives has completed. The technique further includes determining that processing the first plurality of graphics primitives has completed for a last tile included in the plurality of tiles and that the acknowledgement has been received for each tile included in the plurality of tiles, and, in response, releasing a buffer entry associated with the first buffer address.

One embodiment of the present invention sets forth a technique for redistributing geometric primitives generated by tessellation and geometry shaders for processing by multiple graphics pipelines. Geometric primitives that are generated in a first processing cycle are collected and redistributed more evenly and in smaller tasks to the multiple graphics pipelines for vertex processing in a second processing cycle. The smaller tasks do not exceed the resource limits of a graphics pipeline and the per-vertex processing workloads of the graphics pipelines in the second cycle are balanced and make full use of resources. Therefore, the performance of the tessellation and geometry shaders is improved.

Time slice processing of tessellation and geometry shaders

One embodiment of the present invention sets forth a technique for redistributing geometric primitives generated by tessellation and geometry shaders for per-vertex by multiple graphics pipelines. Geometric primitives that are generated in a first processing stage are collected and redistributed more evenly and in smaller batches to the multiple graphics pipelines for vertex processing in a second processing stage. The smaller batches do not exceed the resource limits of a graphics pipeline and the per-vertex processing workloads of the graphics pipelines in the second stage are balanced. Therefore, the performance of the tessellation and geometry shaders is improved.

Redistribution of generated geometric primitives

One embodiment of the present invention sets forth a technique for using a shared memory to store hardware-managed virtual buffers. A circular buffer is allocated within a general-purpose multi-use cache for storage of primitive attribute data rather than having a dedicated buffer for the storage of the primitive attribute data. The general-purpose multi-use cache is also configured to store other graphics data sinces the space requirement for primitive attribute data storage is highly variable, depending on the number of attributes and the size of primitives. Entries in the circular buffer are allocated as needed and released and invalidated after the primitive attribute data has been consumed. An address to the circular buffer entry is transmitted along with primitive descriptors from object-space processing to the distributed processing in screen-space.

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Madison, AL, United States of America

Cynthia Ann Edgeworth Allison