Trap Handler Architecture for GPU Exception Management

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Solution Overview

Problem

Current GPUs lack an efficient trap handler architecture to handle exceptions and interrupts due to their highly parallelized nature, leading to dependency on the host CPU and limitations in feature sets such as direct exception handling and system call support.

Innovation Solution

A trap handler architecture for GPUs that includes a controller to manage disruption events by halting all thread groups, setting an error status register, and redirecting the program counter to a trap handler code segment, allowing the GPU to handle exceptions and interrupts internally.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a trap handler architecture is implemented in a highly parallel GPU to handle exceptions and interrupts internally, then the GPU's independence from the host CPU improves and feature sets are enhanced, but the device complexity and design verification efforts increase

Engineering Contradiction:
ImproveGPU independence from host CPUVSAvoiddesign complexity and verification efforts
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The trap handler architecture is segmented into distinct functional units: a trap handler controller for managing disruption events, an error status register for storing exception information, and a trap handler code segment for execution. This segmentation allows each component to be independently designed and verified, reducing overall design complexity while enabling internal exception handling in the highly parallel GPU environment

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The trap handler controller acts as an intermediary between the parallel thread groups and the host CPU. When an exception or interrupt occurs, the controller intercepts the disruption event, manages the error status register, and coordinates the redirect to the trap handler code segment. This intermediary mechanism enables the GPU to handle exceptions internally without direct host CPU involvement, improving automation while managing complexity through a dedicated control component

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If all thread groups are halted and redirected to a trap handler code segment to handle exceptions, then exception handling capability improves, but the productivity of thread group execution decreases

Engineering Contradiction:
Improveexception handling capabilityVSAvoidthread group execution efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The trap handler architecture implements periodic action by halting thread groups only when a disruption event occurs, rather than continuously. The trap handler controller monitors for exceptions and interrupts, and when detected, temporarily redirects execution to the trap handler code segment. After handling the disruption, thread groups resume normal execution. This periodic intervention maintains high productivity during normal operation while providing reliable exception handling when needed

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2483772B1Trap handler architecture for a parallel processing unit
Publication Date: 2015.11.11 NVIDIA CORP
  • EP2483772B1 patent drawingFigure 1
  • EP2483772B1 patent drawingFigure 2
  • EP2483772B1 patent drawingFigure 3A

AI summary

A trap handler architecture is incorporated into a parallel processing subsystem such as a GPU. The trap handler architecture minimizes design complexity and verification efforts for concurrently executing threads by imposing a property that all thread groups associated with a streaming multi-processor are either all executing within their respective code segments or are all executing within the trap handler code segment.