深入理解Go语言内存管理：VSIZE、RSIZE与垃圾回收机制

package main

import (
    "fmt"
    "runtime"
    "time"
)

func main() {
    var m runtime.MemStats
    runtime.ReadMemStats(&m)
    fmt.Printf("初始内存统计:\n")
    fmt.Printf("  Alloc = %v MiB\n", bToMb(m.Alloc))
    fmt.Printf("  TotalAlloc = %v MiB\n", bToMb(m.TotalAlloc))
    fmt.Printf("  Sys = %v MiB\n", bToMb(m.Sys))
    fmt.Printf("  NumGC = %v\n", m.NumGC)
    fmt.Printf("  PauseTotalNs = %v ms\n", m.PauseTotalNs/uint64(time.Millisecond))
    fmt.Println("--------------------")

    // 模拟一些内存分配
    var data []byte
    for i := 0; i < 10000; i++ {
        data = append(data, make([]byte, 1024)...) // 分配1KB
    }
    fmt.Printf("分配后内存统计:\n")
    runtime.ReadMemStats(&m)
    fmt.Printf("  Alloc = %v MiB\n", bToMb(m.Alloc))
    fmt.Printf("  TotalAlloc = %v MiB\n", bToMb(m.TotalAlloc))
    fmt.Printf("  Sys = %v MiB\n", bToMb(m.Sys))
    fmt.Printf("  NumGC = %v\n", m.NumGC)
    fmt.Printf("  PauseTotalNs = %v ms\n", m.PauseTotalNs/uint64(time.Millisecond))
    fmt.Println("--------------------")

    // 强制GC并再次查看
    runtime.GC()
    fmt.Printf("GC后内存统计:\n")
    runtime.ReadMemStats(&m)
    fmt.Printf("  Alloc = %v MiB\n", bToMb(m.Alloc))
    fmt.Printf("  TotalAlloc = %v MiB\n", bToMb(m.TotalAlloc))
    fmt.Printf("  Sys = %v MiB\n", bToMb(m.Sys))
    fmt.Printf("  NumGC = %v\n", m.NumGC)
    fmt.Printf("  PauseTotalNs = %v ms\n", m.PauseTotalNs/uint64(time.Millisecond))
}

func bToMb(b uint64) uint64 {
    return b / 1024 / 1024
}

package main

import (
    "log"
    "net/http"
    _ "net/http/pprof" // 导入pprof包，它会在默认的HTTP服务器上注册/debug/pprof端点
    "os"
    "runtime/pprof"
    "time"
)

func main() {
    // 启动一个HTTP服务器来暴露pprof接口
    go func() {
        log.Println(http.ListenAndServe("localhost:6060", nil))
    }()

    // 也可以手动生成内存profile文件
    f, err := os.Create("memprofile.prof")
    if err != nil {
        log.Fatal("could not create memory profile: ", err)
    }
    defer f.Close() // 确保文件关闭

    // 模拟一些内存分配
    var largeSlice []byte
    for i := 0; i < 1000; i++ {
        largeSlice = append(largeSlice, make([]byte, 1024*1024)...) // 每次分配1MB
        time.Sleep(10 * time.Millisecond)
    }

    // 写入内存profile
    if err := pprof.WriteHeapProfile(f); err != nil {
        log.Fatal("could not write memory profile: ", err)
    }

    // 保持程序运行以便通过HTTP接口访问pprof
    select {}
}

package main

import (
    "bytes"
    "fmt"
    "sync"
    "time"
)

// 定义一个对象池，用于复用bytes.Buffer
var bufferPool = sync.Pool{
    New: func() interface{} {
        // 创建一个新的bytes.Buffer，并预分配一些空间
        return new(bytes.Buffer)
    },
}

func processRequest(data string) string {
    // 从池中获取一个bytes.Buffer
    buf := bufferPool.Get().(*bytes.Buffer)
    // 使用完毕后，确保将缓冲区放回池中，并重置其内容
    defer func() {
        buf.Reset() // 重置缓冲区，清空内容
        bufferPool.Put(buf)
    }()

    buf.WriteString("Processed: ")
    buf.WriteString(data)
    buf.WriteString(" at ")
    buf.WriteString(time.Now().Format(time.RFC3339))
    return buf.String()
}

func main() {
    for i := 0; i < 10; i++ {
        result := processRequest(fmt.Sprintf("Request %d", i))
        fmt.Println(result)
        time.Sleep(100 * time.Millisecond)
    }
}