Parallelizing the Ethereum Virtual Machine (EVM) has been a topic of interest to many in the cryptocurrency space in recent weeks.
Parallelization increases transaction throughput and improves blockchain scalability by executing multiple transactions simultaneously rather than in the order in which they arrive.
However, Rachel Bousfield, tech lead at Offchain Labs, told Blockworks in an interview that people often overstate the value of parallelism.
“The kinds of returns and rate reductions that people expect don’t really materialize in practice,” Bousfield said. “When people often talk about reducing fees due to parallelism, this is often done because of other issues surrounding it.”
Read more: Parallelized EVMs are gaining popularity, but they cannot scale blockchains alone
Bousfield explains that different blockchains have different hardware requirements. In the case of Ethereum, the blockchain is designed to ensure that running a node is relatively cheap and that low-end computers can make meaningful contributions to the Ethereum network in the form of running applications or running validators.
This differs from other blockchains, which allow for parallelism, but the cost requirements for running a node become much higher.
Ryan Watkins is co-founder of Syncracy Capital, on Solana – a network that enables parallelism. According to a post from Watkins, the cost of running a node is estimated to be five times more expensive than Ethereum nodes. He said the network currently has an estimated 40% of the number of nodes that Ethereum has.
“If Ethereum wanted to, they could dramatically increase the requirements and costs of running an Ethereum validator, and you would see performance improve, there would be more capacity and the cost for people would be lower, but is that really the kind of scaling Ethereum wants in its future? It is not clear to me that that would be an advisable decision,” Bousfield said.
Read more: Scaling Ethereum’s virtual machine is a “solvable problem,” says Monad Labs’ Galler
Additionally, Bousfield notes that parallelism allows throughput to improve efficiency when multiple users want to do different types of things in crypto at the same time.
“The problem is that in real life, the real demand we see on these blockchain networks is when people want to do very similar things with each other. When there’s an airdrop, everyone wants to hit it at the same time. When there is a price difference between DEXs, everyone wants to rush and get MEV arbitrage out,” Bousfield said.
She notes that the technical term to describe this type of activity is called “conflict,” adding that gas prices are often at their highest when multiple people are hoping to do the same thing.
In fact, a recent study from Polygon Labs shows that parallelism applies to about 55% of transactions in most blocks on the network.
“This means that if the parallelism were perfect, had a million cores and ran very, very fast to the point where everything parallelized was executed immediately, you could at best double Polygon’s capacity,” she explained.
That said, Bousfield notes that parallelism is not a bad thing in itself, but it is not the panacea that many anticipate.
In addressing the issue around transaction speeds and ways to increase throughput, Bousfield notes that Arbitrum Stylus achieves this by making it easier for hardware to read and interpret data.
In a traditional EVM, when the hardware receives data, it must check for accuracy, enable branching, and simulate it in memory – steps that often take a long time. Bousfield, on the other hand, notes that Stylus is designed to speak the language of the central processing unit (CPU).
“By removing that layer of interpretation, Stylus can achieve 10-100x speedups on all computing workloads,” she says. “I think strategies like this will yield the big payoffs.”