DSP Recirculation Path for Low Latency Compute

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Solution Overview

Problem

Current digital signal processor (DSP) architectures face challenges in reducing latency and meeting the performance requirements of high-intensity applications, such as base stations in wireless systems, due to limitations in computation speed and power consumption, often necessitating the use of expensive and inflexible combinations with ASICs and FPGAs.

Innovation Solution

A DSP architecture is designed with a compute array featuring a serial connection of compute engines, allowing data and instructions to recirculate directly between the initial and final compute engines within a single clock cycle, reducing latency and optimizing performance through a recirculation path that bypasses intermediate engines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data and instructions circulate through all compute engines in a DSP, then all compute engines can process the data, but latency increases due to the time required for data to traverse each engine

Engineering Contradiction:
Improvecomputation throughputVSAvoidlatency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The compute array is segmented into multiple compute engines (e.g., eight compute engines) that can independently process data. This segmentation allows the system to balance between throughput (all engines working) and latency (direct recirculation path bypassing intermediate engines).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A recirculation path acts as an intermediary mechanism that enables data to return from the final compute engine to the initial compute engine. This recirculation path can operate in two modes: through all compute engines for high throughput, or directly for low latency, allowing the system to switch between operational modes as needed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If DSP performance is increased to meet high-intensity application requirements, then computation speed improves, but power dissipation increases

Engineering Contradiction:
Improvecomputation speedVSAvoidpower dissipation
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The DSP architecture implements dynamic operation modes where compute engines can be selectively activated or deactivated based on application requirements. This allows the system to adjust computation speed and power consumption dynamically, enabling high-performance operations when needed while conserving power during normal operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system can change operational parameters such as the number of active compute engines, clock frequency, and data flow patterns to optimize the balance between computation speed and power dissipation. The recirculation mechanism allows flexible parameter adjustment without hardware changes.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If multiple computation blocks are used to increase DSP performance, then computation capability improves, but latency increases as instructions circulate among computation blocks

Engineering Contradiction:
Improvecomputation capabilityVSAvoidlatency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The computation blocks are segmented into discrete compute engines within a compute array, each capable of independent operation. This segmentation enables selective activation of engines based on task requirements, reducing unnecessary circulation latency while maintaining high computation capability through parallel processing of different data streams.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recirculation path enables continuous data flow through the compute engines without interruption or idle circulation. Data can continuously recirculate from the final engine back to the initial engine, maintaining productive computation across all engines while avoiding wasted time in non-productive data movement.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentUS8108653B2Processor architectures for enhanced computational capability and low latency
Publication Date: 2012.01.31 ANALOG DEVICES INC
  • US8108653B2 patent drawing
  • US8108653B2 patent drawing
  • US8108653B2 patent drawing

AI summary

A processor includes a compute array comprising a first plurality of compute engines serially connected along a data flow path such that data flows between successive compute engines at successive times. The first plurality of compute engines includes an initial compute engine and a final compute engine. The data flow path includes a recirculation path connecting the final compute engine to the initial compute engine with no compute engine therebetween.