Parallel Compare Logic Units for Content Addressable Memory Throughput
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Solution Overview
Problem
Content addressable memories (CAMs) face limitations in efficiently performing parallel lookups, leading to bottlenecks and high costs in expanding their throughput capabilities.
Innovation Solution
The implementation of multiple parallel compare logic units within a common memory module allows for simultaneous comparison of multiple lookup keys against a plurality of entries in a single memory operation cycle, reducing the transistor count and enabling cost-effective expansion of CAMs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple separate memory modules are used to enable parallel lookups, then throughput capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the comparison function by introducing multiple parallel compare logic units that can simultaneously compare different lookup keys against the same memory entries. This functional segmentation enables parallel lookups without requiring separate memory modules, thereby improving throughput while avoiding the complexity and cost of multiple memory modules.
Solution Approach 2:
The common memory module is designed to serve multiple functions by storing entries that can be compared against multiple different lookup keys simultaneously through the parallel compare logic units. This multi-functionality allows a single memory module to support parallel lookups, eliminating the need for multiple specialized memory modules and reducing overall system complexity.
2Productivity
If multiple separate memory modules are used to enable parallel lookups, then throughput capability is improved, but cost increases
Solution Approach 1:
The patent merges multiple comparison functions into a single memory module by implementing parallel compare logic units that share the same memory entries. This consolidation eliminates the need for multiple separate memory modules, reducing manufacturing cost while maintaining the ability to perform parallel lookups and improve throughput capability.
3Adaptability or versatility
If traditional CAM architecture is used, then simplicity is maintained, but parallel lookup capability is limited
Solution Approach 1:
The patent applies segmentation to the comparison function by introducing multiple parallel compare logic units that can simultaneously compare different lookup keys against memory entries. This functional segmentation enables parallel lookups while keeping the memory module structure simple and shared, thereby improving adaptability without significantly increasing device complexity.
Data Source
AI summary
Systems and methods are provided for a content addressable memory. A system includes a common memory module configured to store a plurality of entries, ones of the entries being defined by a string of bits. A first parallel compare logic unit is configured to compare a first lookup key against a plurality of entries stored in the memory module in a first memory operation cycle and to output a match indication indicating a match between the first lookup key and the string of bits of an entry from among the plurality of entries. A second parallel compare logic unit is configured to compare, in the first memory operation cycle, a second lookup key against the plurality of entries stored in the memory module and to output a match indication indicating a match between the second lookup key and the string of bits of an entry from among the plurality of entries.