SonicChain: A Wait-free, Pseudo-Static Approach Toward Concurrency in Blockchains

Abstract: Blockchains have a two-sided reputation: they are praised for disrupting some of our institutions through innovative technology for good, yet notorious for being slow and expensive to use. In this work, we tackle this issue with concurrency, yet we aim to take a radically different approach by valuing simplicity. We embrace the simplicity through two steps: first, we formulate a simple runtime mechanism to deal with conflicts called concurrency delegation. This method is much simpler and has less overhead, particularly in scenarios where conflicting transactions are relatively rare. Moreover, to further reduce the number of conflicting transactions, we propose using static annotations attached to each transaction, provided by the programmer. These annotations are pseudo-static: they are static with respect to the lifetime of the transaction, and therefore are free to use information such as the origin and parameters of the transaction. We propose a distributor component that can use the output of this pseudo-static annotations and use them to effectively distribute transactions between threads in the least-conflicting way. We name the outcome of a system combining concurrency delegation and pseudo-static annotations as SonicChain. We evaluate SonicChain for both validation and authoring tasks against a common workload in blockchains, namely, balance transfers, and observe that it performs expectedly well while introducing very little overhead and additional complexity to the system.