Performance optimization of golang function return value

Performance can be significantly improved by optimizing Go function return value allocation. Methods include: Value semantic optimization: the return value type is changed to value semantics and allocated on the stack. Preallocation optimization: objects are allocated and stored in advance, and functions return references. Pointer optimization: When a reference value needs to be returned, return the pointer to avoid heap allocation.

Performance optimization of Go function return value

In Go, the return value of a function is usually allocated on the heap. This is slower than allocating on the stack, especially in frequently called functions. By optimizing return value allocation, performance can be significantly improved.

Value semantic optimization

First of all, you should consider optimizing the return value type to value semantics. This means that the return value type can be copied, rather than referenced. For example, we can optimize *[]int to []int. This will cause the returned slice to be allocated on the stack rather than on the heap.

// 优化前
func GetNumbers() *[]int {
    return &[]int{1, 2, 3}
}

// 优化后
func GetNumbers() []int {
    return []int{1, 2, 3}
}

Pre-allocation optimization

If a function always returns the same type of object, we can pre-allocate the object and store it in a global variable. This way, the function can return a reference to a preallocated object instead of creating a new object each time.

var numbers = []int{1, 2, 3}

func GetNumbers() []int {
    return numbers
}

Pointer optimization

In some cases, we may need to return a reference value. To avoid allocating objects on the heap, we can return a pointer.

// 优化前
func GetInfo() map[string]interface{} {
    return map[string]interface{}{"name": "John", "age": 30}
}

// 优化后
func GetInfo() *map[string]interface{} {
    info := map[string]interface{}{"name": "John", "age": 30}
    return &info
}

Practical case: HTTP response

We often use the following code when processing HTTP responses:

func GetResponse() (*http.Response, error) {
    return http.Get("https://example.com")
}

After using value semantics optimization, you can The code is optimized to:

func GetResponse() (http.Response, error) {
    var resp http.Response
    err := http.Get("https://example.com")
    return resp, err
}

This will cause the resp value to be allocated on the stack, thus improving performance.

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