zkevm-benchs

Benchmarks for different approaches to implementing a zkEVM.

1. EVM inside risc0: risc0 is a 32-bit RISC-V virtual machine based on zkSTARK that generates zero-knowledge proofs for programs. In this solution, we run an Ethereum Virtual Machine (EVM) on risc0 to achieve zkEVM.

2. PSE zkEVM-circuits: Ethereum Foundation's zkEVM project, using halo2, KZG polynomial commitment, bn256 curve, build circuits.

📑 Report

Here we test representative ERC20 transfer transactions, followed by iterative calculations using keccak256 to test the maximum computational capacity supported by zkevm.

ERC20 contract

contract OpenZeppelinERC20TestToken is ERC20 {
    constructor(address owner) ERC20("TestToken1", "TT1") {
        _mint(owner, 999999 * 18 ** decimals());
    }
}

Keccak256 Contract

contract Keccak256Recursive {
  bytes32 _x;
  
  constructor(bytes32 x) {
    _x = x;
  }
  
  function compute(uint k) public returns(bytes32) {
    if (k == 0) {
      return _x;
    } else {
      bytes memory res = new bytes(32);
      assembly {
        mstore(add(res, 32), sload(_x.slot))
      }
      for (uint i = 0; i < k; i++) {
        bytes32 hash;
        assembly {
          hash := keccak256(add(res, 32), 32)
        }
        assembly {
          mstore(add(res, 32), hash)
        }
      }
      bytes32 finalResult;
      assembly {
        finalResult := mload(add(res, 32))
      }
      _x = finalResult;
      return finalResult;
    }
  }
}

test environment: 16 cores, 128GB RAM

1️⃣ EVM inside risc0

• erc20 transfer (successful): 3m25s
• erc20 transfer (failed): failed to generate proof
• keccak256 computes (100): 6m47s
• keccak256 computes (500): 28m51s
• keccak256 computes (1000): failed to generate proof (limit exceeded)
• keccak256 computes (3000): failed to generate proof (limit exceeded)
• keccak256 computes (5000): failed to generate proof (limit exceeded)

2️⃣ PSE zkEVM-circuits

Due to the proof generation of PSE/zkevm-circuits is composed of multiple modules, its super circuit is responsible for combining proofs from individual sub-modules (sub-circuits). However, currently, the super circuit has a issue and fails the test. Therefore, here we are conducting separate tests for each sub-module, which are as follows:

• bytecode_circuit
• copy_circuit
• evm_circuit
• exp_circuit
• keccak_circuit
• state_circuit
• tx_circuit

As we know, zkevm-circuits are written using Halo2, which utilizes the Plonkish frontend, and proves the execution trace. This process requires converting the trace columns into polynomials using fft. As a result, the proof generation time is directly proportional to the length of the trace.

For the first test, we set the parameters as below.

const MAX_RWS: usize = 5888;
const MAX_BYTECODE: usize = 5000;
const MAX_COPY_ROWS: usize = 5888;
const MAX_EVM_ROWS: usize = 10000;
const MAX_EXP_STEPS: usize = 1000;
const MAX_KECCAK_ROWS: usize = 15000;

Sub-Circuit	ERC20-transfer (success)	ERC20-transfer (fail)	Keccak256 (100)	Keccak256 (500)	Keccak256 (1000)	Keccak256 (3000)	Keccak256 (5000)
Bytecode	13.4s	13.2s	failed	failed	failed	failed	failed
Copy	25s	24.8s	failed	failed	failed	failed	failed
EVM	11m5s	9m40s	failed	failed	failed	failed	failed
Exp	6.59s	6.59s	failed	failed	failed	failed	failed
Keccak	3m8s	3m49s	failed	failed	failed	failed	failed
State	2m21s	2m3s	failed	failed	failed	failed	failed
Tx	4m55s	5m1s	failed	failed	failed	failed	failed

Then we make the parameters larger as below.

const MAX_RWS: usize = 58888;
const MAX_BYTECODE: usize = 58888;
const MAX_COPY_ROWS: usize = 58888;
const MAX_EVM_ROWS: usize = 58888;
const MAX_EXP_STEPS: usize = 1000;
const MAX_KECCAK_ROWS: usize = 58888;

Sub-Circuit	ERC20-transfer (success)	ERC20-transfer (fail)	Keccak256 (100)	Keccak256 (500)	Keccak256 (1000)	Keccak256 (3000)	Keccak256 (5000)
Bytecode	51.56s	50.57s	50.56s	failed (rws=91828)	failed (rws=182828)	failed (rws=546828)	failed (rws=910828)
Copy	28.63s	26.51s	27.00s	failed	failed	failed	failed
EVM	9m11s	8m52s	9m2s	failed	failed	failed	failed
Exp	6.6s	6.6s	6.6s	failed	failed	failed	failed
Keccak	2m41s	2m32s	3m28s	failed	failed	failed	failed
State	2m59s	3m31s	2m40s	failed	failed	failed	failed
Tx	4m58s	5m2s	4m44s	failed	failed	failed	failed