Dynamic Routing for NoC-Based DNN Accelerators

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Solution Overview

Problem

Deep neural network (DNN) accelerators with network-on-chip (NoC) architecture face challenges in efficiently managing channel congestion and power consumption due to asymmetric computing loads and unbalanced network traffic, leading to idle buffers and increased latency.

Innovation Solution

A method is introduced to dynamically select routing schemes based on compiler information, employing buffer gating control and contention-free switching when congestion is low, and adaptive routing algorithms when congestion occurs, to minimize energy consumption and avoid deadlock and livelock in NoC systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If buffer gating control and contention-free switching are used, then energy consumption is reduced, but channel congestion occurs leading to increased latency

Engineering Contradiction:
Improveenergy consumptionVSAvoidlatency
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent implements dynamic routing scheme selection that adapts to changing network conditions. The system monitors compiler information including channel bandwidths and NoC throughput to determine when to switch between first routing scheme (buffer gating control) and second routing scheme (adaptive routing), allowing the system to optimize for energy consumption under low congestion while avoiding latency penalties when congestion occurs

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes routing parameters based on compiler information about channel bandwidths and throughput requirements. By analyzing whether bandwidth requirements meet throughput capabilities, the system selects appropriate routing schemes, effectively using parameter changes to resolve the contradiction between energy efficiency and latency performance

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If adaptive routing algorithm is used, then channel congestion is avoided, but energy consumption increases due to continuous buffer operation

Engineering Contradiction:
ImprovelatencyVSAvoidenergy consumption
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The system dynamically selects between adaptive routing and buffer gating control based on real-time assessment of compiler information. When channel bandwidths indicate congestion risks, adaptive routing is activated to maintain low latency; when conditions permit, the system switches to buffer gating control to minimize energy consumption, thus dynamically balancing the latency-energy tradeoff

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If network-on-chip architecture is used for DNN accelerators, then design flexibility and scalability are improved, but channel congestion and unbalanced traffic increase leading to idle buffers

Engineering Contradiction:
Improvedesign flexibilityVSAvoidenergy consumption
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent employs feedback mechanisms by monitoring compiler information about channel bandwidths and NoC throughput to assess network congestion conditions. This feedback drives the selection of routing schemes, allowing the system to respond to actual traffic patterns and congestion levels, thereby reducing idle buffer energy consumption while maintaining the flexibility benefits of NoC architecture

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-service by autonomously selecting appropriate routing schemes based on compiler information without external intervention. The NoC-based DNN accelerator automatically assesses its own congestion conditions and adjusts routing behavior accordingly, enabling it to service its own energy optimization needs while maintaining design flexibility

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS20240028881A1Deep neural network (DNN) compute loading and traffic-aware power management for multi-core artificial intelligence (AI) processing system
Publication Date: 2024.01.25 MEDIATEK INC
  • US20240028881A1 patent drawing
  • US20240028881A1 patent drawing
  • US20240028881A1 patent drawing

AI summary

Aspects of the present disclosure provide a method for controlling a processing device to execute an application that runs on a neural network (NN). The processing device can include a plurality of processing units that are arranged in a network-on-chip (NoC) architecture. For example, the method can include obtaining compiler information relating the application and the NoC, controlling the processing device to employ a first routing scheme to process the application when the compiler information does not meet a predefined requirement, and controlling the processing device to employ a second routing scheme to process the application when the compiler information meets the predefined requirement.