MethodId Sort Optimization

In the contract, all functions are organized into an array and systematically sorted by their MethodID, a unique identifier for each function. This organization not only streamlines the management of function calls but also facilitates quick access by imposing a structured order that can be efficiently searched during function executions.

When a function is called, the system does not immediately execute the function but begins a sequential search through the function array. It uses the MethodID to accurately locate and execute the intended function.

During this search process, each iteration of comparing MethodIDs incurs a gas cost of 22 units. This cost is associated with the computational effort required by the Ethereum Virtual Machine (EVM) to read and compare MethodIDs.

To optimize gas usage, particularly in contracts with numerous functions, it is advantageous for developers to order functions based on their frequency of calls. Placing the most commonly called functions at the beginning of the array can reduce the number of iterations needed for most calls, thereby reducing the overall gas costs and improving the efficiency of the contract.

DemoCode In this example, calling the func2_r3o function saves 66 gas per call compared to calling func1. Assuming func2 is the most frequently called function, optimizing it to func2_r3o and positioning its MethodID at the beginning of the array reduces comparison costs.

contract Optimizer {
    // methodID: 0x74135154 
    // gas: 142
    function func1() external {
    }

    // methodId: 0xb1ade4db
    // gas: 164 
    function func2() external {
    }

    // methodId: 0x013d45d6
    // gas:120
    function func3() external {
    }

    // methodId: 0x000029ed
    // gas:98
    function func2_r3o() external {
    }
}

关于 gas 优化的建议：

🌟 通过根据函数调用频率对函数进行排序，并将调用次数最多的函数放在数组的顶部，我们可以降低 gas 成本，并且这种优化对高频操作尤为明显。