Hybrid Cache Architecture for Large AV Simulation Objects

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Solution Overview

Problem

Autonomous vehicle (AV) simulation systems face challenges with high network bandwidth demands and potential SLA violations due to heavy cloud access, necessitating an efficient caching solution to reduce backend access and optimize data storage.

Innovation Solution

A hybrid cache system combining a consistent hash cache and a hot cache, with the latter having a two-tier structure, is implemented to manage large data objects like drive bags, optimizing storage and access times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single-tier cache is used, then the system is simpler, but it cannot simultaneously optimize for high-speed access and large storage capacity

Engineering Contradiction:
Improvedata access speedVSAvoidcache structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cache is divided into two distinct tiers: a first tier with high-speed storage nodes for fast access to frequently used data, and a second tier with capacity-optimized storage nodes for storing less frequently accessed data. This segmentation allows the system to simultaneously achieve high access speeds for hot data while maintaining large overall storage capacity, resolving the contradiction between speed and complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If data is replicated across multiple nodes, then access reliability improves, but storage efficiency decreases

Engineering Contradiction:
Improvedata access reliabilityVSAvoidstorage efficiency
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Different replication strategies are applied to different tiers based on their specific requirements. The first tier uses replication across multiple high-speed nodes to ensure high access reliability and availability for frequently accessed data. The second tier uses more efficient storage methods with controlled replication to maintain data durability while maximizing storage capacity. This localized application of replication strategies optimizes both reliability and storage efficiency for each tier.

Inventive Principle:
Principle #3Local quality

3Loss of time

If all data is stored in high-speed storage, then access time is reduced, but the system cannot handle diverse workload demands

Engineering Contradiction:
Improvedata access timeVSAvoidworkload handling capability
Core Design Contradiction:
Loss of timeVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts to different workload demands by intelligently distributing data between the two tiers based on access patterns and workload characteristics. The load balancer continuously monitors and adjusts data placement, moving frequently accessed data to the high-speed first tier and less frequently accessed data to the capacity-optimized second tier. This dynamic adaptation allows the system to efficiently handle diverse workload demands while optimizing access times for different data types.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS12487934B2Hybrid cache for autonomous vehicle infrastructure
Publication Date: 2025.12.02 GM CRUISE HOLDINGS LLC
  • US12487934B2 patent drawing
  • US12487934B2 patent drawing
  • US12487934B2 patent drawing

AI summary

A method of caching large data objects of greater than 1 GB, comprising: populating a sharded cache with large data objects backfilled from a data store; servicing large data object requests from a plurality of worker nodes via the sharded cache, comprising deterministically addressing objects within the sharded cache; and if a number of requests for an object within a time exceeds a threshold: after receiving a request from a worker node for the object, sending the worker node a redirect message directed to a hot cache, wherein the hot cache is to backfill from a hot cache backfill, and wherein the hot cache backfill is to backfill from the sharded cache.