Dynamic Cache Policy for Graph Neural Networks

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Solution Overview

Problem

Graph neural networks (GNNs) face challenges in efficiently managing large graphs due to size constraints, leading to thrashing and high bandwidth and power consumption when selecting nodes for storage and communication, as standard static cache policies are not optimal for GNNs with power-law distributed nodes.

Innovation Solution

A dynamically adjustable cache policy is developed using reinforcement learning to continuously adapt and optimize cache behavior based on graph patterns, combining policies like LRU and LFU to reduce thrashing and improve training time, along with subgraph compression to reduce communication overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If standard static cache policies (LRU, LFU) are used for graph storage, then the cache management is simple and deterministic, but the cache thrashing increases and training time increases due to power-law distributed nodes

Engineering Contradiction:
Improvecache management complexityVSAvoidtraining time
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies dynamics by transitioning from static cache policies (LRU, LFU) to a dynamic cache policy that adapts to graph characteristics. The system learns graph properties during training and adjusts cache eviction strategies in real-time, allowing the cache to respond to changing access patterns and graph structures, thereby reducing thrashing and improving training efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of cache policy from fixed to adaptive. By monitoring cache hit rates and graph statistics, the system modifies eviction parameters dynamically. This includes adjusting replacement thresholds, prioritizing nodes based on learned importance, and adapting to different graph topologies, which optimizes cache performance for power-law distributed nodes.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If larger graphs are stored in cache to reduce cache misses, then cache hit rate improves, but cache capacity constraints are violated and more nodes must be evicted

Engineering Contradiction:
Improvecache hit rateVSAvoidnumber of nodes stored in cache
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by differentiating the treatment of different nodes based on their importance and access patterns. Instead of uniform eviction, the system identifies and prioritizes retaining critical nodes (those with high degree, high connectivity, or high access frequency) while evicting less important nodes. This localized differentiation maximizes cache hit rate within capacity constraints.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system implements self-service through automated learning and adaptation. The cache management mechanism automatically monitors performance, learns from access patterns, and adjusts eviction strategies without manual intervention. This self-optimizing approach continuously improves cache hit rate while maintaining appropriate node quantities based on actual workload characteristics.

Inventive Principle:
Principle #25Self-service

3Quantity of substance

If more nodes are evicted from cache to accommodate graph size, then cache capacity is maintained, but communication bandwidth and power consumption increase

Engineering Contradiction:
Improvecache capacity utilizationVSAvoidpower consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-computing and storing graph statistics, node importance metrics, and access patterns before actual processing. This advance preparation allows the cache system to make informed eviction decisions that minimize future cache misses, reducing the need for frequent data transfers between cache and storage, thereby lowering power consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms that continuously monitor cache performance metrics (hit rates, miss rates, access patterns) and use this information to adjust eviction policies. This closed-loop control optimizes the balance between cache capacity utilization and energy consumption by learning from actual workload patterns and adapting strategies to minimize unnecessary data movements.

Inventive Principle:
Principle #23Feedback

4Loss of information

If subgraphs are communicated from host processor to hardware accelerator without compression, then data integrity is maintained, but communication bandwidth and latency increase

Engineering Contradiction:
Improvedata integrityVSAvoidcommunication speed
Core Design Contradiction:
Loss of informationVSSpeed

Solution Approach 1:

The patent applies the extraction principle by selectively removing redundant or less important information from subgraph data before communication. The system identifies and extracts only the essential node and edge information needed for processing, compressing the data representation to reduce communication bandwidth requirements while maintaining data integrity for the hardware accelerator's processing needs.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS20220261357A1Dynamicaly adjusted cache policy and compression scheme for graphs processed by graph neural networks
Publication Date: 2022.08.18 INTEL CORP
  • US20220261357A1 patent drawing
  • US20220261357A1 patent drawing
  • US20220261357A1 patent drawing

AI summary

Systems, apparatuses, and methods include technology that determines, with a neural network, that a first eviction node stored in a cache will be evicted from the cache based on a cache policy. The first eviction node is part of a plurality of nodes associated with a graph. Further, a subset of nodes of the plurality of nodes remains in the cache after the eviction of the first eviction node from the cache. The technology further tracks a number of cache hits on the cache during an aggregation operation associated with a hardware accelerator, where the aggregation operation is executed on the subset of nodes that remain in the cache after the eviction of the eviction node from the cache. The technology executes a training process on the neural network to adjust the cache policy based on the number of the cache hits.