Context Switch Signaling for GPU Processing Engines

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Solution Overview

Problem

Conventional context switching in computer systems with graphics processing units (GPUs) experiences variable delays due to processing engines not performing context switches immediately, leading to inefficiencies in scheduling and increased overhead for the host unit.

Innovation Solution

A method and system where the host unit sends a separate context switch request to the processing engine, suspending method transmission until an acknowledgement signal is received, allowing the engine to compare and perform context switches locally without requiring knowledge of its current context, thus enabling precise scheduling with minimal overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the host unit tracks variable delays to achieve precise context switch scheduling, then scheduling precision is improved, but host unit overhead increases significantly

Engineering Contradiction:

Improvecontext switch scheduling precisionVSAvoidhost unit overhead

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The processing engine autonomously manages context switch timing by monitoring its own execution state and generating context switch requests when ready, eliminating the need for the host unit to track variable delays and perform complex scheduling calculations

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of the host unit scheduling context switches based on delay tracking, the processing engine itself initiates context switch requests when it determines switching is appropriate, inverting the traditional control relationship

Inventive Principle:

Principle #13The other way round (Inversion)

2Loss of time

If the processing engine performs context switch immediately upon request, then context switch delay is reduced, but the processing pipeline may be disrupted

Engineering Contradiction:

Improvecontext switch delayVSAvoidprocessing pipeline efficiency

Core Design Contradiction:

Loss of timeVSProductivity

Solution Approach 1:

The processing engine prepares for context switches in advance by monitoring its execution state and queue conditions, generating context switch requests before the FIFO is empty, allowing smooth transitions without pipeline disruption

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The processing engine continuously monitors its own state (current context, queue depth, execution progress) and uses this feedback to determine the optimal moment to initiate context switches, balancing immediate response with pipeline continuity

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7937710B1Context switch signaling method and system

Publication Date: 2011.05.03 NVIDIA CORP

AI summary

A context switch request is made from a host unit to a processing engine separately from the method stream to that processing engine and does not require the host unit to know what context the processing engine is currently working on. Upon receiving the request, the processing engine compares the requested context with the context that it is currently working on, and if the two are different, performs the context switch to the requested context. On the other hand, if the two are the same, the engine does not perform the context switch and continues working on the current context.