Graphics Clipping Unit Context Switching Optimization

Solution Overview

Problem

Current context switching techniques in graphics processing, such as 'wait for idle' and 'halt style' methods, incur performance penalties due to high response times and excessive execution state information storage and restoration when clipping graphics primitives, especially with multiple clipping planes.

Innovation Solution

A graphics processing apparatus and method that includes a clipping unit and control unit to suspend clipping operations, preserve an initial execution state, and restart clipping from the same state upon context switching, reducing the need for reissuing initial outputs and minimizing the amount of execution state information stored and restored.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the 'wait for idle' technique is used to complete pending clipping work, then the execution state information to be stored and restored is reduced, but the time to complete pending work increases significantly

Engineering Contradiction:

Improveexecution state informationVSAvoidtime to complete pending work

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent segments the clipping output into initial outputs (to be issued before context switch) and subsequent outputs (to be issued after context switch). This segmentation allows the system to preserve only the execution state up to the point of context switching, reducing the amount of state information that needs to be saved while still completing the clipping operation efficiently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by issuing initial outputs before the context switch occurs. The control unit is configured to issue initial outputs based on the execution of a set of clipping operations before switching contexts. This preliminary completion of work reduces the amount of state information that needs to be preserved, as only the state up to the point of context switching needs to be saved.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If the 'halt style' technique is used to halt pending clipping work, then the time to complete pending work is reduced, but the execution state information to be stored and restored increases significantly

Engineering Contradiction:

Improvetime to complete pending workVSAvoidexecution state information

Core Design Contradiction:

Loss of timeVSLoss of information

Solution Approach 1:

The patent segments the clipping output into initial outputs (to be issued before context switch) and subsequent outputs (to be issued after context switch). This segmentation allows the system to preserve only the execution state up to the point of context switching, reducing the amount of state information that needs to be saved while still completing the clipping operation efficiently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by issuing initial outputs before the context switch occurs. The control unit is configured to issue initial outputs based on the execution of a set of clipping operations before switching contexts. This preliminary completion of work reduces the amount of state information that needs to be preserved, as only the state up to the point of context switching needs to be saved.

Inventive Principle:

Principle #10Preliminary action

3Loss of time

If context switching is accelerated by reducing execution state information, then the response time is reduced, but the clipping operations cannot be restarted from the same state

Engineering Contradiction:

Improveresponse timeVSAvoidclipping operation continuity

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent performs preliminary action by issuing initial outputs before the context switch occurs. The control unit is configured to issue initial outputs based on the execution of a set of clipping operations before switching contexts. This preliminary completion of work reduces the amount of state information that needs to be preserved, as only the state up to the point of context switching needs to be saved.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by having the control unit track which outputs have been issued and use this information to determine what needs to be restarted. The control unit is configured to preserve an initial execution state based on an indication that the initial outputs have been issued, and upon context switch, restart clipping from the same state while avoiding reissuing of initial outputs.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8432406B1Apparatus, system, and method for clipping graphics primitives with accelerated context switching

Publication Date: 2013.04.30 NVIDIA CORP

AI summary

An apparatus, system, and method for clipping graphics primitives are described. In one embodiment, a graphics processing apparatus includes a clipping unit that is configured to produce and issue ni initial outputs based on execution of a set of clipping operations, wherein ni represents the number of the initial outputs that are issued by the clipping unit prior to context switching, and the initial outputs partially define a clipped graphics primitive. The graphics processing apparatus also includes a control unit connected to the clipping unit. The control unit is configured to preserve an initial execution state of the clipping unit in response to an initial command for context switching, wherein the initial execution state is preserved based on ni.