pprof

Documentation

Overview

Package pprof serves via its HTTP server runtime profiling data in the format expected by the pprof visualization tool. For more information about pprof, see http://code.google.com/p/google-perftools/.

The package is typically only imported for the side effect of registering its HTTP handlers. The handled paths all begin with /debug/pprof/.

To use pprof, link this package into your program:

import _ "net/http/pprof"

If your application is not already running an http server, you need to start one. Add "net/http" and "log" to your imports and the following code to your main function:

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

Then use the pprof tool to look at the heap profile:

go tool pprof http://localhost:6060/debug/pprof/heap

Or to look at a 30-second CPU profile:

go tool pprof http://localhost:6060/debug/pprof/profile

Or to look at the goroutine blocking profile, after calling runtime.SetBlockProfileRate in your program:

go tool pprof http://localhost:6060/debug/pprof/block

Or to collect a 5-second execution trace:

wget http://localhost:6060/debug/pprof/trace?seconds=5

To view all available profiles, open http://localhost:6060/debug/pprof/ in your browser.

For a study of the facility in action, visit

https://blog.golang.org/2011/06/profiling-go-programs.html

Index

• func Cmdline(w http.ResponseWriter, r *http.Request)
• func Handler(name string) http.Handler
• func Index(w http.ResponseWriter, r *http.Request)
• func Profile(w http.ResponseWriter, r *http.Request)
• func Symbol(w http.ResponseWriter, r *http.Request)
• func Trace(w http.ResponseWriter, r *http.Request)

Functions

func Cmdline

func Cmdline(w http.ResponseWriter, r *http.Request)

Cmdline responds with the running program's command line, with arguments separated by NUL bytes. The package initialization registers it as /debug/pprof/cmdline.

func Handler

func Handler(name string) http.Handler

Handler returns an HTTP handler that serves the named profile.

func Index

func Index(w http.ResponseWriter, r *http.Request)

Index responds with the pprof-formatted profile named by the request. For example, "/debug/pprof/heap" serves the "heap" profile. Index responds to a request for "/debug/pprof/" with an HTML page listing the available profiles.

func Profile

func Profile(w http.ResponseWriter, r *http.Request)

Profile responds with the pprof-formatted cpu profile. The package initialization registers it as /debug/pprof/profile.

func Symbol

func Symbol(w http.ResponseWriter, r *http.Request)

Symbol looks up the program counters listed in the request, responding with a table mapping program counters to function names. The package initialization registers it as /debug/pprof/symbol.

func Trace

func Trace(w http.ResponseWriter, r *http.Request)

Trace responds with the execution trace in binary form. Tracing lasts for duration specified in seconds GET parameter, or for 1 second if not specified. The package initialization registers it as /debug/pprof/trace.