Golang Profile Usage

This is a creation in Article, where the information may have evolved or changed.

Profile

Profile is timed sampling, collecting CPU, memory and other information, and then give performance optimization guidance, Golang official provided Golang own performance analysis tool usage, also gave the guidance, the official introduction

Environment

Golang Environment, Graphviz

Generate Profile method

Golang currently provides 3 profiles, CPU profiles, memery profiles, blocking profile, two ways to generate these profiles, one is to use net/http/pprof packages, One is the need to write your own code, the following separate introduction

1. Net/http/pprof method

This method is very very simple, just need to introduce the NET/HTTP/PPROF package on the page can be viewed

package mainimport (    "fmt"    "log"    "net/http"    _ "net/http/pprof")func main() {    go func() {        for {            fmt.Println("hello world")        }    }()    log.Fatal(http.ListenAndServe("0.0.0.0:8080", nil))}

Http://127.0.0.1:8080/debug/pprof View overall information
Http://127.0.0.1:8080/debug/pprof/profile can download CPU profile to observe the analysis

Enter profile from terminal for detailed analysis
Go Tool pprof Http://localhost:6060/debug/pprof/profile
Go Tool pprof Http://localhost:6060/debug/pprof/heap
Go Tool pprof Http://localhost:6060/debug/pprof/block

1. How to write code

func main() {    cpuf, err := os.Create("cpu_profile")    if err != nil {        log.Fatal(err)    }    pprof.StartCPUProfile(cpuf)    defer pprof.StopCPUProfile()    ctx, _ := context.WithTimeout(context.Background(), time.Second*5)    test(ctx)    time.Sleep(time.Second * 3)    memf, err := os.Create("mem_profile")    if err != nil {        log.Fatal("could not create memory profile: ", err)    }    if err := pprof.WriteHeapProfile(memf); err != nil {        log.Fatal("could not write memory profile: ", err)    }    memf.Close()}func test(c context.Context) {    i := 0    j := 0    go func() {        m := map[int]int{}        for {            i++            m[i] = i        }    }()    go func() {        m := map[int]int{}        for {            j++            m[i] = i        }    }()    select {    case <-c.Done():        fmt.Println("done, i", i, "j", j)        return    }}

Generates two profiles, one for the CPU and one for the memory. Enter the Proflie method

Go tool pprof Main profile
Main represents a binary file, which is a compiled executable file.
Profile is the profile generated above, can be cpu_profile, or it can be mem_profile

For Cpu_profile, it's time to start counting when the code starts.
Mem_profile part of the code if the code at the beginning of the location is not statistical, you need to find a better location

How to analyze Profile

1. Enter profile according to the method described above (Go tool pprof)

2. View Profile

After entering the profile, you can use the Help command to see which commands are available, use them according to instructions, common commands TopN, list, and so on, or you can use Web commands to draw a graphical analysis of what the browser can see