A profiler collects runtime measurements to help diagnose slow execution, lock contention, blocked goroutines, and possible memory leaks. In Go, pprof provides CPU, goroutine, heap, mutex, and block profiles. Exposing pprof does not mean CPU profiling runs continuously: it starts when requested. section 12.8.1
package main
import (
"fmt"
"log"
"net/http"
_ "net/http/pprof" #1
)
func main() {
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { #2
fmt.Fprintf(w, "")
})
log.Fatal(http.ListenAndServe(":80", nil))
}
The blank import of net/http/pprof adds profiling endpoints to an HTTP server. It is a convenient way to make profiles available, including in production. section 12.8.1
Request /debug/pprof/profile to collect a CPU profile for 30 seconds by default. During collection, the profiler samples execution about every 10 ms. Use the resulting profile to find where the application spends time rather than guessing from the code. section 12.8.1
$ go tool pprof -http=:8080 <file>
Open a saved profile with go tool pprof to inspect its call graph. For a benchmark, the -cpuprofile option can save the profile first. section 12.8.1
