Broadcast Hub for Multi-Processor Deadlock Prevention

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Solution Overview

Problem

Multi-processor arrangements face challenges such as deadlocks and inefficiencies in signal packet transfer due to routing complexities and congestion, particularly in neural network inference operations, which require efficient communication between multiple processing units.

Innovation Solution

Implementing a broadcast hub within the multi-processor arrangement to manage and distribute signal packets, utilizing separate virtual channels for request and response signals and employing routing rules like vertical-first or horizontal-first to prevent deadlocks, and incorporating an asymmetrical interconnect with a data flow controller to enhance bandwidth and reduce energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electronic interconnects are implemented to couple multiple processors, then communication between processing units is enabled, but routing complexities and deadlocks occur

Engineering Contradiction:
Improvecommunication capabilityVSAvoidrouting complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A broadcast hub is introduced as an intermediary component between processors and memory systems. The hub receives broadcast requests from any processor and distributes them to all other processors simultaneously, eliminating complex peer-to-peer routing logic and preventing deadlocks by centralizing the broadcast function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Multiple communication functions (broadcast requests, broadcast responses, point-to-point communications) are merged into a single interconnect infrastructure managed by the broadcast hub. This consolidation simplifies the overall system architecture by providing a unified communication pathway rather than requiring separate dedicated channels for each communication type.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If traditional routing methods are used for signal packet transfer, then basic communication is achieved, but congestion and deadlocks reduce efficiency

Engineering Contradiction:
Improvesignal packet transfer efficiencyVSAvoiddeadlock-free operation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The communication protocol is segmented into distinct phases: broadcast request phase and broadcast response phase. Virtual channels are assigned to separate these phases, allowing request packets to be transmitted without blocking response packets, thereby preventing deadlocks and improving overall transfer efficiency through non-blocking communication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically assigns virtual channels based on communication phase and type. The broadcast hub can flexibly manage channel allocation to optimize flow control, adapting to different communication patterns and preventing congestion by dynamically adjusting packet routing decisions based on current system state.

Inventive Principle:
Principle #15Dynamics

3Productivity

If symmetrical interconnects are used, then simple architecture is maintained, but bandwidth and energy efficiency are insufficient for neural network operations

Engineering Contradiction:
ImprovebandwidthVSAvoidinterconnect architecture
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The interconnect architecture transitions from symmetrical to asymmetrical design, where the broadcast hub has differentiated connection characteristics to memory systems versus connections to processors. This asymmetry optimizes bandwidth for memory-bound neural network operations by providing dedicated high-capacity pathways from the hub to memory, while maintaining simpler processor interfaces.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Different interconnect qualities are provided for different communication needs: high-bandwidth asymmetric channels connect the broadcast hub to memory systems for data-intensive neural network operations, while standard channels connect processors to the hub for control and coordination functions, optimizing overall system performance for the dominant workload.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11874793B2Broadcast hub for multi-processor arrangement
Publication Date: 2024.01.16 ARM LTD
  • US11874793B2 patent drawing
  • US11874793B2 patent drawing
  • US11874793B2 patent drawing

AI summary

The present disclosure relates generally to multi-processor arrangements and, more particularly, to broadcast hubs for multi-processor arrangements. A processing tile may comprise a broadcast hub to obtain a plurality of parameters applicable in a particular operation from at least one of a plurality of processing tiles and initiate distribution of the plurality of parameters to the plurality of processing tiles, wherein the plurality of processing tiles may execute the particular operation based at least in part on the plurality of distributed parameters.