Go pprof cheat sheet

As you know, “What is measured, improves”. So, if you can measure the performance of you application, you can improve it accordingly. Go programming language has pprof for measuring performance of your apps written in Go.

Enable profiling in Go application 🔗

Default http server 🔗

If you are using the default http server handler, enable profiling like that.

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

//...

return http.ListenAndServe(":8081", nil)

Non-default server 🔗

If you are using a custom http server handler, enable profiling like that.

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

//...

mux := http.NewServeMux()

mux.HandleFunc("/debug/pprof/", pprof.Index)
mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
mux.HandleFunc("/debug/pprof/trace", pprof.Trace)

// ...

server := &http.Server{
  Addr:    ":8081",
  Handler: mux,
}

return server.ListenAndServe()

Memory 🔗

To gain access to pprof data in the Go service (e.g from Kubernetes).

kubectl -n my-ns port-forward svc/my-app 8081:8081

To get the memory profile.

curl -s http://127.0.0.1:8081/debug/pprof/heap > ./heap.pprof

To load and read profile.

go tool pprof -http=:8080 ./heap.pprof

Additional info for reading 🔗

• inuse_space: amount of memory allocated and not released yet (important).
• inuse_objects: amount of objects allocated and not released yet.
• alloc_space: total amount of memory allocated (regardless of released).
• alloc_objects: total amount of objects allocated (regardless of released).

CPU 🔗

To gain access to pprof data in the Go service (e.g from Kubernetes).

kubectl -n my-ns port-forward svc/my-app 8081:8081

To get the CPU profile.

By default will be 30s of CPU profile:

curl -s http://127.0.0.1:8081/debug/pprof/profile > ./cpu.pprof

To customize the time with ?seconds=N:

curl -s http://127.0.0.1:8081/debug/pprof/profile?seconds=60 > ./cpu.pprof

To load and read CPU profile.

go tool pprof -http=:8080 ./cpu.pprof

or

go tool pprof -web cpu.pprof

CPU trace 🔗

To gain access to pprof data in the Go service (e.g from Kubernetes).

kubectl -n my-ns port-forward svc/my-app 8081:8081

To get the CPU trace profile.

By default will be 1s of CPU trace profile:

curl -s http://127.0.0.1:8081/debug/pprof/trace > ./cpu-trace.pprof

To customize the time with ?seconds=N:

curl -s http://127.0.0.1:8081/debug/pprof/trace?seconds=60 > ./cpu-trace.pprof

To load and read profile of the CPU trace.

go tool trace -http=:8080 ./cpu-trace.pprof

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