Go has really good profiling tools built into the standard library.

cpu profiling - stack sampling
heap profiling - small amount of allocations are sampled including call stack
block profiling - lock contentions

tracing, etc all in pprof

Ways to profile:
1. Instrument your binary during testing and benchmarking:
go test -cpuprofile -memprofile

2. import _ net/http/pprof that exposes /debug/pprof endpoints to your app
        - Once those are enabled a simple command will take a sample:
          go tool pprof -seconds 5 http://localhost:5000/debug/pprof/profile

3. for debugging memory leaks or something really difficult, you can
instrument things in your application where you think the issue is. 
        runtime.StartCPUProfile or runtime.WriteHeapProfile

go tool pprof will analyze these profiles.



### To run benchmarks
go test -bench . -benchmem -cpuprofile prof.cpu

go tool pprof stats.test prof.cpu

Fetched 1 source profiles out of 2
Main binary filename not available.
Type: cpu
Time: Nov 16, 2017 at 7:29pm (EST)
Duration: 2.24s, Total samples = 2.04s (91.11%)
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) list HashPassword
Total: 2.04s
ROUTINE ======================== skeletor.BenchmarkHashPassword in /Users/Bmercer/gopath/src/skeletor/skeletor_test.go
      10ms      1.78s (flat, cum) 87.25% of Total
         .          .      4:   "skeletor/utils"
         .          .      5:   "testing"
         .          .      6:)
         .          .      7:
         .          .      8:func BenchmarkHashPassword(b *testing.B) {
      10ms       10ms      9:   for i := 0; i < b.N; i++ {
         .      1.77s     10:           utils.HashPassword("password")
         .          .     11:   }
         .          .     12:
         .          .     13:}
ROUTINE ======================== skeletor/utils.HashPassword in /Users/Bmercer/gopath/src/skeletor/utils/utils.go
      70ms      1.77s (flat, cum) 86.76% of Total
         .          .      7:   "io"
         .          .      8:   "net/http"
         .          .      9:)
         .          .     10:
         .          .     11:func HashPassword(password string) string {
         .      250ms     12:   h := sha256.New()
      20ms      110ms     13:   h.Write([]byte(password))
      40ms      1.40s     14:   res := fmt.Sprintf("%x", h.Sum(nil))
      10ms       10ms     15:   return res
         .          .     16:}
         .          .     17:
         .          .     18:func MustEncode(w io.Writer, i interface{}) {
         .          .     19:   if headered, ok := w.(http.ResponseWriter); ok {
         .          .     20:           headered.Header().Set("Cache-Control", "no-cache")