Golang function performance optimization loop optimization technology

Go function loop optimization: avoid unnecessary allocations: allocate and reuse objects once to reduce garbage collection. Loop variable externalization: Move loop variables outside to reduce memory access. Use a for-range loop to traverse the collection efficiently, avoiding explicit indexing. Concurrent execution loop: If the task can be executed in parallel, use Goroutine to execute concurrently. Microbenchmarks: Use microbenchmarks to verify optimization effects and identify improvements.

Go language function performance optimization: loop optimization technology

Loop statements are a common performance bottleneck in code. To improve the performance of Go functions, it is important to optimize loops. This article will introduce several practical loop optimization techniques.

1. Avoid unnecessary allocation

If new objects need to be created within the loop body, try to allocate them once and reuse them. This will reduce pressure on the garbage collector, thus improving performance.

// 糟糕的做法：每次循环都创建新切片
var manySlices []int

for i := 0; i < 10000; i++ {
    manySlices = append(manySlices, i)
}

// 更好的做法：一次性分配切片
var manySlices []int = make([]int, 10000)

for i := 0; i < 10000; i++ {
    manySlices[i] = i
}

2. Lift the loop variable outside the loop

If the loop variable is used in each iteration, please lift it outside the loop. This reduces duplicate memory accesses and improves performance.

// 糟糕的做法：每次循环都读取变量 i
for i := 0; i < 10000; i++ {
    if someCondition(i) {
        // ...
    }
}

// 更好的做法：将 i 外提到循环外部
i := 0
for ; i < 10000; i++ {
    if someCondition(i) {
        // ...
    }
}

3. Use for-range loop to traverse

If you need to traverse collections such as slices, arrays, or maps, please use for-range loop. It efficiently traverses collections via underlying iterators, avoiding the use of explicit indexes.

// 糟糕的做法：使用显式索引遍历切片
for i := 0; i < len(arr); i++ {
    // ...
}

// 更好的做法：使用 for-range 循环遍历切片
for _, v := range arr {
    // ...
}

4. Concurrent execution of loops

If the tasks of the loop can be executed independently in parallel, please use Goroutine to execute them concurrently. This can be achieved by calling the go function or using sync.Pool.

// 并发执行循环任务
func doWorkConcurrently(tasks []func()) {
    wg := sync.WaitGroup{}
    wg.Add(len(tasks))

    for _, task := range tasks {
        go func(task func()) {
            task()
            wg.Done()
        }(task)
    }

    wg.Wait()
}

5. Microbenchmarks

Always use microbenchmarks to measure real performance improvements after applying optimizations. By comparing run times before and after optimization, the effectiveness of the technique can be determined.

import (
    "testing"
)

// 优化前
func BenchmarkUnoptimizedLoop(b *testing.B) {
    // ...
}

// 优化后
func BenchmarkOptimizedLoop(b *testing.B) {
    // ...
}

These techniques can significantly improve the loop performance of Go language functions. By applying these optimization techniques, code can run more efficiently and faster.

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