Cache Partitioning for Multicore Processor Energy Efficiency

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Solution Overview

Problem

High core-count chip multiprocessors face challenges in energy efficiency due to increased static power consumption and the 'power wall' phenomenon, where a significant fraction of cores may not be powered at full frequency, necessitating improved energy efficiency strategies.

Innovation Solution

Implementing cache partitioning and near threshold-voltage design (NTD) to optimize energy efficiency by splitting the cache into partitions for different data sources, allocating and sizing them based on energy or latency costs, and using cost functions to minimize total cache miss costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple processor cores are integrated on a single chip to create a chip multiprocessor, then system performance is improved, but static power consumption increases

Engineering Contradiction:
Improvesystem performanceVSAvoidstatic power consumption
Core Design Contradiction:
ProductivityVSUse of energy by stationary object

Solution Approach 1:

The cache memory is divided into multiple partitions, with each partition dedicated to storing data from a specific data source. This segmentation allows the system to optimize cache usage for different data sources independently, reducing overall power consumption by avoiding unnecessary cache accesses while maintaining high system performance through efficient data retrieval.

Inventive Principle:
Principle #1Segmentation

2Use of energy by stationary object

If cache partitioning is implemented to reduce power consumption, then energy efficiency is improved, but cache management complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcache management complexity
Core Design Contradiction:
Use of energy by stationary objectVSDevice complexity

Solution Approach 1:

Each cache partition is optimized for its specific data source with dedicated replacement policies and management mechanisms. This local optimization approach simplifies the overall cache management by allowing each partition to operate independently with simplified rules, rather than requiring complex global management strategies, thus improving energy efficiency without proportionally increasing complexity.

Inventive Principle:
Principle #3Local quality

3Loss of time

If cache partitions are sized to minimize latency costs, then access speed is improved, but power consumption increases

Engineering Contradiction:
Improvelatency costsVSAvoidpower consumption
Core Design Contradiction:
Loss of timeVSUse of energy by stationary object

Solution Approach 1:

The cache partition sizes and configurations are dynamically adjusted based on the specific requirements of different applications and workloads. By adapting the cache structure to match actual usage patterns, the system achieves low latency costs for frequently accessed data while avoiding the power consumption penalty of maintaining large static cache partitions, thus resolving the trade-off between speed and power consumption.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10346308B2Cache partitioning in a multicore processor
Publication Date: 2019.07.09 EMPIRE TECH DEV LLC
  • US10346308B2 patent drawing
  • US10346308B2 patent drawing
  • US10346308B2 patent drawing

AI summary

Techniques described herein generally include methods and systems related to cache partitioning in a chip multiprocessor. Cache-partitioning for a single thread or application between multiple data sources improves energy or latency efficiency of a chip multiprocessor by exploiting variations in energy cost and latency cost of the multiple data sources. Partition sizes for each data source may be selected using an optimization algorithm that minimizes or otherwise reduces latencies or energy consumption associated with cache misses.