golang pprof meaning

Golang is a high-performance, concurrent, compiled language. Performance analysis is very important when writing high-performance applications. Although Golang took this into consideration in its initial design, in actual production environments, some tools are still needed for performance analysis. One very important tool is pprof .

The full name of pprof is performance profiling, which is a performance analysis tool built into Golang. pprof can help developers analyze the CPU usage, memory usage, etc. when the program is running, so as to find the performance bottleneck of the program.

pprof works based on sampling. pprof will periodically collect the CPU usage, memory usage and other data of the application when it is running, and then generate a sampling file (.prof file). Users can use this file to analyze the performance of the program.

In order to use pprof, we need to add some specific code snippets to the program code. These code snippets capture some key information when the program is running and write this information into a sample file. After the program runs, we can use the standard go tool pprof tool to analyze the sample file.

The following is a basic usage example:

import (
    "net/http"
    _ "net/http/pprof"
)

func main() {
    go func() {
        http.ListenAndServe("localhost:6060", nil)
    }()
    // 代码片段
}

In the above code, we imported the net/http/pprof package and started an HTTP server in the main function for monitoring Request from pprof. Then, we insert some code snippets at key locations in the program. These code snippets capture the program's CPU usage, stack information, etc. and write this information into a sample file.

After the program is finished running, we can use the following command to start the pprof tool:

go tool pprof [binary] [profile]

Where [binary] is the binary file that needs to be analyzed, [profile] is the path to the sampling file . After starting the pprof tool, you can use commands such as top, web, list, etc. to view the information in the sampling file.

top The command can view the CPU usage and memory usage of the program, and sort it by CPU usage:

(pprof) top
Showing nodes accounting for 1030ms, 100% of 1030ms total
Dropped 105 nodes (cum <= 5.15ms)
Showing top 10 nodes out of 21
      flat  flat%   sum%        cum   cum%
     990ms 96.12% 96.12%      990ms 96.12%  main.(*myStruct).doWork
      20ms  1.94% 98.06%       20ms  1.94%  time.Sleep
      20ms  1.94% 100.00%      20ms  1.94%  fmt.(*buffer).write
         0     0% 100.00%     1030ms   100%  runtime.main
         0     0% 100.00%     1030ms   100%  runtime.main.func1
         0     0% 100.00%     1030ms   100%  runtime.mstart
         0     0% 100.00%     1030ms   100%  runtime.mstart1
         0     0% 100.00%     1030ms   100%  runtime.systemstack
         0     0% 100.00%      990ms 95.63%  main.work
         0     0% 100.00%       20ms  1.94%  fmt.Fprintf

web The command can generate An interactive web interface that more intuitively displays the performance bottlenecks of the program: The

(pprof) web

list command can view the detailed information of a function and display the source code and CPU usage of the function. :

(pprof) list myStruct.doWork
Total: 1.03s
ROUTINE ======================== main.(*myStruct).doWork in /path/to/main.go
  990ms   990ms (flat, cum) 96.12% of Total
         0     10ms   0.00%  runtime.newstack
         0     10ms   0.00%  runtime.procresize
         0     10ms   0.00%  runtime.systemstack
...

pprof is a very practical performance analysis tool that can help developers quickly find application performance bottlenecks and optimize them. pprof is an indispensable tool when we write high-performance applications.

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