Cache Memory Huffman Compression for Low-Overhead Data Access

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Solution Overview

Problem

Existing memory systems face inefficiencies in storing redundant data values due to overheads in accessing and modifying values, particularly with statistical-based compression techniques, which slow down access times and are not effectively applicable in computer memory systems.

Innovation Solution

A cache system utilizing a Huffman-based compression/decompression scheme with a many-to-one mapping between reference and value space, allowing for variable-length codewords based on value frequency, and a dynamic mechanism to track value frequencies and construct Huffman trees, enabling efficient compression and decompression with reduced access overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If statistical-based compression techniques are used to store redundant data values, then memory storage efficiency is improved, but access time increases and becomes too slow for computer memory systems

Engineering Contradiction:
Improvememory storage efficiencyVSAvoidaccess time
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The system performs preliminary action by pre-computing and storing the Huffman code mapping table during system initialization or idle periods. This table maps each possible data value to its compressed codeword representation. During actual memory operations, the system simply looks up pre-computed codes rather than performing statistical analysis and code generation on-the-fly, thereby achieving fast compression without sacrificing storage efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adapts the compression approach based on the specific access pattern and data characteristics. For frequently accessed data with high redundancy, aggressive Huffman compression is applied. For data requiring frequent writes or with low redundancy, the system may use lighter compression or store data uncompressed. This dynamic adaptation allows the system to optimize between storage efficiency and access speed based on actual workload requirements.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If Huffman-based compression with variable-length codewords is implemented, then data storage compactness is improved, but device complexity increases due to dynamic Huffman tree construction and tracking mechanisms

Engineering Contradiction:
Improvedata storage compactnessVSAvoidcompression mechanism complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The system pre-computes the Huffman code mapping table during initialization, performing the complex statistical analysis and tree construction work before actual memory operations begin. This preliminary action eliminates the need for complex real-time computation during memory access, reducing operational complexity while maintaining compression effectiveness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of implementing complex dynamic Huffman tree construction and maintenance logic during memory operations, the system creates a simplified copy of the compression functionality in the form of a static lookup table. This table copy contains all the compression information needed, allowing the system to achieve compression without the complexity of dynamic tree management during operations.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If value frequency tracking and dynamic Huffman tree construction are performed, then compression adaptability is improved, but processing overhead and energy consumption increase

Engineering Contradiction:
Improvecompression adaptabilityVSAvoidprocessing overhead
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The system performs frequency analysis and Huffman tree construction as preliminary actions during system initialization or during idle periods when the memory is not being actively accessed. This timing strategy ensures that the energy-intensive processing occurs when it does not interfere with normal memory operations, reducing perceived processing overhead and allowing the system to maintain adaptability without continuous energy expenditure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements periodic re-computation of Huffman codes at predetermined intervals or when triggered by specific events such as cache misses or changes in data access patterns. This periodic action maintains compression adaptability to changing workloads while avoiding continuous processing overhead, as the system can operate with existing code tables between periodic updates.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentUS9330001B2Cache system and a method of operating a cache memory
Publication Date: 2016.05.03 ZEROPOINT TECH AB
  • US9330001B2 patent drawing
  • US9330001B2 patent drawing
  • US9330001B2 patent drawing

AI summary

In one embodiment, a computer cache is extended with structures that can (1) establish the frequency by which distinct values occur in the cache and use that information to (2) compress values in caches into dense codes using a plurality of statistical-based compression techniques and (3) decompress densely coded values to realize caches that can store information densely that can be retrieved with low overhead.