Dedicated Digital Interface for Multi-GPU Synchronization

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Solution Overview

Problem

Conventional multi-processor graphics processing systems experience visual artifacts such as tearing and color variations due to differences in video timing and DAC calibration between graphics adapters when rendering images.

Innovation Solution

A dedicated digital interface connects two graphics adapters, allowing for the transfer of digital pixel data and synchronization signals between a master and slave graphics adapter, with the master adapter generating video timing and converting digital pixel data for display, thereby eliminating artifacts from DAC mismatches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple graphics adapters are connected via PCI bus with separate DACs, then graphics processing performance is increased through parallel rendering, but visual artifacts such as tearing and color variations occur due to differences in video timing and DAC calibration

Engineering Contradiction:

Improvegraphics processing performanceVSAvoidimage quality consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent merges multiple graphics adapters into a unified rendering system where multiple GPUs render different portions of the same frame simultaneously, combining their outputs through a dedicated interface to produce a single coherent image, thereby maintaining high performance while eliminating artifacts

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a dedicated interface as an intermediary between multiple graphics adapters, which synchronizes video timing and coordinates DAC operations to ensure consistent image quality across all adapters while maintaining parallel processing capability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If separate DACs are used in each graphics adapter, then each adapter can independently convert digital to analog signals, but DAC calibration differences between adapters introduce color variations and visual artifacts

Engineering Contradiction:

Improveindependent signal conversion capabilityVSAvoidcolor consistency

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The dedicated interface acts as an intermediary that synchronizes DAC operations across multiple graphics adapters, coordinating their calibration and timing to produce consistent color output while preserving the ability of each adapter to independently convert digital signals

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If graphics adapters are connected through broadcast instructions via PCI bus, then system complexity is reduced using standard interfaces, but video timing differences between adapters cause synchronization issues and visual artifacts

Engineering Contradiction:

Improvesystem interface complexityVSAvoidvideo timing synchronization

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The dedicated interface serves as an intermediary layer between the PCI bus and multiple graphics adapters, providing centralized timing control and synchronization signals that coordinate video output across all adapters while maintaining compatibility with standard PCI bus architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system establishes equipotential timing relationships between multiple graphics adapters through the dedicated interface, ensuring that all adapters operate from a common timing reference point, thereby eliminating synchronization issues while preserving standard interface connectivity

Inventive Principle:

Principle #12Equipotentiality

Data Source

PatentUS7477256B1Connecting graphics adapters for scalable performance

Publication Date: 2009.01.13 NVIDIA CORP

AI summary

A system and method for providing a dedicated digital interface between multiple graphics devices. The dedicated interface provides a point-to-point connection between each of the multiple graphics devices for the transfer of digital pixel data and synchronization signals. Graphics processing, including combining of portions of a displayable image, is distributed between the multiple graphics devices. One of the multiple graphics devices, a master graphics device converts the combined portions of the displayable image as needed for a specific display device.