Programmable Fabric Control Circuits for QoS Management

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Solution Overview

Problem

Designing a communication fabric for complex digital systems is challenging due to incomplete information and the risk of over- or under-design, leading to performance and functionality issues, as existing predesigned circuits often fail to meet performance goals.

Innovation Solution

Incorporating programmable fabric control circuits within the communication fabric to control aspects such as transaction limiting, bandwidth management, and quality of service (QoS), which can be dynamically adjusted to optimize performance and functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If predesigned fabric circuits are used, then device complexity is reduced, but performance goals cannot be met due to over- or under-design

Engineering Contradiction:
Improvefabric design complexityVSAvoidperformance goal achievement
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces dynamically reconfigurable fabric control circuits that can be programmed at runtime to adjust bandwidth allocation, transaction limits, and QoS parameters. This dynamic adaptability allows the fabric to optimize performance for different workloads and components, resolving the contradiction between using simple predesigned circuits and meeting specific performance goals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent enables modification of fabric parameters such as bandwidth limits, transaction counts, and QoS settings through programmable control circuits. These parameter changes allow the fabric to adapt to different performance requirements without changing the physical structure, thus maintaining simplicity while achieving performance goals.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If fabric is overdesigned to meet performance goals, then performance requirements are satisfied, but resources are wasted

Engineering Contradiction:
Improveperformance goal achievementVSAvoidresource wastage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements transaction limiters and bandwidth limiters that enforce partial action by restricting the number of outstanding transactions or bandwidth consumption to specific thresholds. This prevents excessive resource usage while still allowing sufficient performance for legitimate workloads, thus avoiding over-design waste.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The programmable fabric control circuits monitor actual fabric usage and performance metrics, then adjust bandwidth allocation and transaction limits dynamically based on observed conditions. This feedback mechanism ensures resources are allocated efficiently based on actual needs rather than worst-case assumptions, preventing resource wastage.

Inventive Principle:
Principle #23Feedback

3Loss of energy

If fabric is underdesigned to save resources, then resource usage is reduced, but performance and functionality are compromised

Engineering Contradiction:
Improveresource efficiencyVSAvoidperformance goal achievement
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent employs dynamically reconfigurable control circuits that can increase bandwidth allocation and transaction limits when performance goals are not being met. This dynamic scaling allows the fabric to maintain resource efficiency during normal operation while automatically providing additional capacity when needed to achieve performance targets.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements QoS parameters and traffic shapers that prepare and prioritize transactions in advance based on their importance and deadlines. By preliminarily organizing traffic and allocating bandwidth reserves for critical transactions, the fabric can maintain high performance for important functions without over-provisioning resources for all traffic equally.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If multiple components with different communication requirements are connected, then system functionality is enhanced, but fabric design becomes error-prone

Engineering Contradiction:
Improvecomponent compatibilityVSAvoidfabric design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal fabric control interface that can be programmed to support different component types and communication requirements through a single programmable controller. This multi-functional approach allows diverse components to be connected without requiring custom fabric designs for each scenario, reducing design complexity while maintaining versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The programmable fabric control circuits act as intermediaries between components with different communication requirements, translating and mediating their diverse protocols and requirements into unified fabric transactions. This intermediary layer simplifies the overall fabric design by providing a standard interface that handles component-specific complexities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2477119B1Quality of service(QOS)-related fabric control
Publication Date: 2014.04.16 APPLE INC
  • EP2477119B1 patent drawingFigure 1
  • EP2477119B1 patent drawingFigure 2~3
  • EP2477119B1 patent drawingFigure 4~5

AI summary

In an embodiment, one or more fabric control circuits may be inserted in a communication fabric to control various aspects of the communications by components in the system. The fabric control circuits may be included on the interface of the components to the communication fabric, in some embodiments. In other embodiments that include a hierarchical communication fabric, fabric control circuits may alternatively or additionally be included. The fabric control circuits may be programmable, and thus may provide the ability to tune the communication fabric to meet performance and/or functionality goals.