`go tool pprof` 报告错误 `unrecognized profile format`

Question

我正在尝试使用此演示生成 goroutine 配置文件的 PNG，但它报告错误 parsing profile: unrecognized profile format. failed to fetch any source profiles

package main

import (
    "fmt"
    "log"
    "os"
    "os/exec"
    "runtime/pprof"
    "time"
)

func main()  {
    // start demo go routine
    go func() {
        for {
            time.Sleep(time.Second)
        }
    }()

    // get executable binary path
    exePath, err := os.Executable()
    if err != nil {
        log.Println(err.Error())
        return
    }
    log.Println("exePath", exePath)

    // generate goroutine profile
    profilePath := exePath + ".profile"
    f, err := os.Create(profilePath)
    if err != nil {
        log.Println(err.Error())
        return
    }
    defer f.Close()
    if err := pprof.Lookup("goroutine").WriteTo(f, 2); err != nil {
        log.Println(err.Error())
        return
    }

    // generate PNG
    pngPath := exePath + ".png"
    result, err := exec.Command("go", "tool", "pprof", "-png", "-output", pngPath, exePath, profilePath).CombinedOutput()
    if err != nil {
        log.Println("make error:", err.Error())
    }
    log.Println("make result:", string(result))
}

Answer 1

您正在 pprof.Lookup("goroutine").WriteTo(f, 2) 中使用调试值 2。这将产生一个 pprof 工具无法解析的输出，它意味着人类可直接阅读。

来自 pprof.(*Profile).WriteTo 文档：

The debug parameter enables additional output. Passing debug=0 writes the gzip-compressed protocol buffer described in https://github.com/google/pprof/tree/master/proto#overview. Passing debug=1 writes the legacy text format with comments translating addresses to function names and line numbers, so that a programmer can read the profile without tools.

The predefined profiles may assign meaning to other debug values; for example, when printing the "goroutine" profile, debug=2 means to print the goroutine stacks in the same form that a Go program uses when dying due to an unrecovered panic.

将此行更改为 pprof.Lookup("goroutine").WriteTo(f, 0) 即可解决问题。

此外，与问题无关，但您可能需要考虑关闭文件 f.Close()，然后再在 pprof 命令中使用它。 WriteTo 应该将文件刷新到磁盘，但这不会造成伤害。

if err := pprof.Lookup("goroutine").WriteTo(f, 2); err != nil {
    log.Println(err.Error())
    return
}

if err := f.Close(); err != nil {
    log.Println(err.Error())
    return
}

// generate PNG
...

`go tool pprof` 报告错误 `unrecognized profile format`

`go tool pprof` reports error `unrecognized profile format`

go

goroutine

pprof