Documentation

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))
    }()
    

    If you are not using DefaultServeMux, you will have to register handlers with the mux you are using.

    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?seconds=30
    

    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 look at the holders of contended mutexes, after calling runtime.SetMutexProfileFraction in your program:

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

    The package also exports a handler that serves execution trace data for the "go tool trace" command. To collect a 5-second execution trace:

    wget -O trace.out http://localhost:6060/debug/pprof/trace?seconds=5
    go tool trace trace.out
    

    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

    Constants

    This section is empty.

    Variables

    This section is empty.

    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. Profiling lasts for duration specified in seconds GET parameter, or for 30 seconds if not specified. 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.

                Types

                This section is empty.

                Source Files