NoC Router Bypass Channels for Idle Power Management

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Solution Overview

Problem

Conventional Network on Chip (NoC) architectures experience significant data transmission delays due to the need for routers to be re-enabled after being powered off for idle periods, which increases power consumption and delays data transmission.

Innovation Solution

The introduction of bypass channels and a controller that allows data to be transmitted through these channels when a router is idle, ensuring continuous data transmission by determining the next-hop router based on destination addresses and using link buffers with gating to manage power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If power gating technology is used to cut off router power when idle, then router power consumption is reduced, but data transmission delay increases due to router re-enabling requirements

Engineering Contradiction:
Improverouter power consumptionVSAvoiddata transmission delay
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The router is segmented into multiple functional modules (routing computation module, virtual channel allocator and switch allocator, crossbar, FIFO queue). Each module can be independently powered on or off based on its current working state, allowing partial power savings while maintaining critical data transmission functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The controller predicts future data transmission requirements in advance and proactively re-enables router modules before data arrives. This preliminary action prevents transmission delays by ensuring routers are ready before needed, while avoiding unnecessary power consumption by only enabling modules when predicted to be required.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 3:

The system implements a feedback mechanism where the controller monitors router working states and data transmission paths, then adjusts power gating decisions accordingly. When data transmission is detected or predicted on a path, the controller re-enables routers along that path, creating a responsive power management system that balances energy savings with transmission performance.

Inventive Principle:
Principle #23Feedback

2Speed

If routers are kept in working state to avoid transmission delay, then data transmission speed is maintained, but overall NoC power consumption increases

Engineering Contradiction:
Improvedata transmission speedVSAvoidNoC power consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The router power state is made dynamic rather than static. Routers transition between powered-off and powered-on states based on real-time traffic patterns and predicted data transmission needs. This dynamic adaptation allows the system to optimize the balance between transmission speed and power consumption by keeping routers enabled only when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of routers based on traffic conditions. By monitoring data transmission patterns and predicting future needs, the controller adjusts router power states to match actual demand, reducing power consumption during low-traffic periods while maintaining transmission performance during high-traffic periods.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3214822B1Network on chip, communication control method and controller
Publication Date: 2020.05.27 HUAWEI TECH CO LTD
  • EP3214822B1 patent drawingFigure 1
  • EP3214822B1 patent drawingFigure 2
  • EP3214822B1 patent drawingFigure 3

AI summary

A network on chip NoC, a communication control method, and a controller can avoid a data transmission delay. The NoC includes multiple routers and multiple network interfaces NIs, each router in the multiple routers is connected to one local node device by using one NI, and each router includes one output port connected to an NI, one input port connected to the NI, multiple output ports connected to other routers, and multiple input ports connected to other routers; there is an input bypass channel between the output port that is connected to an NI and of each router and each input port that is connected to another router and of the router. There is an output bypass channel between the input port that is connected to an NI and of each router and each output port that is connected to another router and of the router.