Run Format

Package pprof

import "net/http/pprof"

Overview ▾

Package pprof serves via its HTTP server runtime profiling data in the format expected by the pprof visualization tool.

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


func Cmdline

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

func Handler

Handler returns an HTTP handler that serves the named profile.

func Handler(name string) http.Handler

func Index

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

func Profile

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

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

func Symbol

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

func Trace

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.

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