Ephemeral Rollups are All you Need (2311.02650v4)

Abstract: In the realm of open and composable gaming, we envision platforms where users actively expand, create, engage, and immerse themselves in a rich world of entertainment. One promising avenue for achieving this vision is through fully on-chain (FOC) games, where both game state and logic reside on the blockchain, maximizing composability. However, we must grapple with inherent limitations and trade-offs, particularly in terms of costs and scalability. This paper proposes a framework that leverages the Solana Virtual Machine (SVM) to scale FOC games without state fragmentation or compromised trust assumptions. The framework introduces a systematic approach for discovering, utilizing, and publishing modular pieces of logic as components deeply rooted in the Entity-Component-System (ECS) pattern. To enhance scalability and resource optimization, we introduce the concept of Ephemeral Rollups (ERs) that overcome the tradeoffs of L2 horizontal scaling. These dedicated runtimes can be customized to provide higher operational speed, configurable ticking mechanisms, provable sessions and gasless transactions without composability-scalability tradeoffs.

• The paper introduces the BOLT framework that uses Ephemeral Rollups to scale fully on-chain games efficiently.
• It leverages the Solana Virtual Machine and an ECS pattern to manage high-frequency transactions and modular game logic.
• The framework ensures state composability and robust security through optimistic rollups and zk-proofs for reliable decentralized gaming.

Ephemeral Rollups are All you Need

The paper "Ephemeral Rollups are All you Need" by Gabriele Picco and Andrea Fortugno introduces the BOLT framework, a novel approach to scaling Fully On-Chain (FOC) games. Leveraging the Solana Virtual Machine (SVM), BOLT presents key innovations aimed at enhancing the scalability and resource optimization of FOC games without compromising trust or state-composability.

FOC Games Definition and Attributes

FOC games place their logic and state entirely on the blockchain, ensuring a singular source of truth that guarantees transparency, immutability, and resiliency. This structure allows for permissionless composability—anyone can expand upon existing games without needing the original creator’s consent. Essential attributes for FOC games include:

1. Blockchain as Single Source of Truth: All game logic and states are stored on-chain.
2. Permissionless Composability: Extensions and modifications can be made freely.
3. Persistency: Ensuring resilience and continuity despite potential failures of centralized components.

The core belief underlying this approach is that FOC games will drive the development of self-reliant ecosystems blending virtual and physical worlds.

BOLT Framework Overview

Addressing the challenge of real-time game scalability, BOLT introduces Ephemeral Rollups (ERs) to leverage the parallelization capabilities of the SVM. This paper outlines a systematic approach for organizing game logic through the Entity-Component-System (ECS) pattern, focusing on three key facets: game logic, state, and transactions.

To handle the high-frequency transactions inherent to large-scale multiplayer games, BOLT uses customizable ERs. Here's the ER process briefly outlined:

1. Delegation to ER: Game state accounts are temporarily transferred to the ER, which customizes runtime for higher throughput.
2. ER Computation: ER runs game logic with enhanced speed and specific configurations like gasless transactions or quicker block times.
3. State Settlement: After processing, ER updates the base layer state, ensuring consistency and trust.

Framework Architecture and Implementation Details

The architecture leverages the SVM’s unique account model, distinguishing between executable (program) and non-executable (data) accounts. Importantly, the SVM supports parallel transaction processing, which is crucial for scaling. ERs operate by locking multiple accounts into clusters for processing off the main chain, eventually settling state updates back to L1 if constraints are met.

To route transactions, the BOLT architecture uses an RPC router which dynamically directs requests to either the base layer or the ER based on the state location.

Avoiding Fragmentation

A significant benefit of using ERs is that they avoid fragmenting the game state into isolated rollups. Instead, the programs execute on the base layer while leveraging ERs for performance, maintaining seamless integration with the ecosystem’s full state and resources. This allows developers to benefit from Solana’s robust infrastructure, including existing libraries, deployment tools, and client software.

Illustrative Example

An illustrative use case presents a game tracking player positions and providing rewards based on reaching specific areas. The game logic delegates position accounts to the ER while retaining control of reward distribution accounts on the base layer. Thus, high-frequency state updates occur efficiently in the ER, while critical transactions involving rewards update directly on-chain.

Performance Considerations

Evaluating the potential throughput and latency benefits vis-a-vis existing solutions like Nakama, BOLT highlights the scalability advantages. Solana already supports high transaction rates, promising further enhancements with future runtimes like Firedancer. Additionally, ERs can be tailored to achieve lower latencies, potentially matching the responsiveness of traditional multiplayer game servers.

Security and Trustworthiness

ERs incorporate security measures to ensure delegated accounts are not indefinitely locked and computations remain correct. BOLT employs a hybrid approach using optimistic rollups for immediate computation and zk-proofs for subsequent verification. This ensures both speed and correctness, providing robust security.

ECS Pattern and Public Registry

Adhering to ECS architecture, BOLT decouples game logic from state. This modular approach enhances performance and reusability. The authors propose a public components registry to facilitate discovery, sharing, and reuse of on-chain components, significantly aiding rapid game development.

Conclusion and Implications

The BOLT framework presents a powerful method for scaling FOC games, preserving the composability of Solana’s ecosystem while offering lower latency and higher throughput. This approach not only sets the stage for more complex and immersive game experiences but also extends applicability beyond gaming. Future developments might see similar mechanisms applied across other high-frequency transaction domains, leveraging the promise of blockchain technology for robust, decentralized applications.