golang pprof性能分析解析-Go服务器开发

在Go语言中，pprof是一个非常强大的性能分析工具，可以用来识别程序中的瓶颈和内存泄漏等问题。本文将对pprof进行详细解析。

原理

pprof基于采样技术实现性能分析。采样技术会定时中断程序执行，并记录当前正在执行的函数、调用栈信息、堆栈使用情况等数据。通过对这些采样数据进行统计和分析，就可以得到程序运行时每个函数的耗时、CPU占用率、内存占用情况等信息。

使用方法

启动pprof接口

首先，在需要进行性能分析的代码中导入net/http/pprof包，并启动http接口：

import (
    "log"
    "net/http"
    _ "net/http/pprof" // 导入pprof包，启用http接口
)

func main() {
    go func() {
        log.Println(http.ListenAndServe("localhost:6060", nil))
    }()
}

这里我们将http接口监听在了本地6060端口上。

生成pprof文件

在你希望进行性能分析的代码处添加trace代码：

func doSomething() {
    for i := 0; i < 100000; i++ {
        // 添加trace代码
        if i%100 == 0 {
            f, _ := os.Create(fmt.Sprintf("/tmp/profile-%d.pprof", i))
            pprof.StartCPUProfile(f)
            defer pprof.StopCPUProfile()
        }
        // ...
    }
}

在每个100次迭代后，我们将会生成一个pprof文件。这个文件可以在后续使用pprof工具进行分析。

使用pprof工具

通过以下命令使用pprof工具进行性能分析：

go tool pprof /path/to/executable /path/to/profile.pprof

其中，/path/to/executable是你的程序可执行文件路径，/path/to/profile.pprof是你刚刚生成的pprof文件路径。

进入pprof交互模式后，输入help可以查看所有支持的命令：

(pprof) help
Commands:
  callgrind    Outputs a graph in callgrind format.
  comments     Output all profile comments to stdout.
  disasm       Disassemble program at symbol+offset range.
  dot          Outputs a graph in DOT format.
  eog          View graph through eog.
  evince       View graph through evince.
  file         Read a profile from a file.
  focus        Focus on subgraph reachable from named nodes only.
  gexec        Executes specified command with remapping of Go source paths based on the profile's mapping information. Currently this only works for cpu profiles (e.g., no go routine data). For example, to launch "go tool pprof" use "gexec go tool pprof [opts]"; the options will be passed through directly to "go tool pprof".
  gif          Outputs an annotated callgraph in GIF format.
  help         Provide help on specified commands, or list available commands
               if none is specified.
  list         Output annotated source for functions matching regexp.
  peek         Output callers/callees of functions matching regexp.
  png          Outputs an annotated callgraph in PNG format.
  proto        Outputs a profile in compressed protobuf format.
  ps           Outputs a graph in PostScript format.
  quit         Exit pprof.
  raw          Outputs a text representation of the raw profile sample
               stream. Intended only for low-level debugging use; requires
               intimate knowledge of the profile.proto schema and is not
               guaranteed to remain stable across releases.
  report       Report generation commands:
    weblist      generate annotated source for functions matching regexp,
                 generates output suitable for "go tool pprof -http :8080"
    text         generate text report (the default)
    pdf          generate pdf report
    svg          generate svg report
    tags         list all tags in the profile

其中，最常用的命令包括：