From e103051eda12ba70a72a5d24dced61705589ba2b Mon Sep 17 00:00:00 2001
From: Yonder Blue <fields@yonder.blue>
Date: Wed, 19 Oct 2022 08:23:32 -0400
Subject: [PATCH] Add clock (fgprof) profile

---
 go.mod          |  2 ++
 profile.go      | 21 +++++++++++++++++++++
 profile_test.go | 16 ++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/go.mod b/go.mod
index 08932f3..6dd15d7 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module github.com/pkg/profile
 
 go 1.13
+
+require github.com/felixge/fgprof v0.9.3
diff --git a/profile.go b/profile.go
index ec66e30..ea4e853 100644
--- a/profile.go
+++ b/profile.go
@@ -12,6 +12,8 @@ import (
 	"runtime/pprof"
 	"runtime/trace"
 	"sync/atomic"
+
+	"github.com/felixge/fgprof"
 )
 
 const (
@@ -22,6 +24,7 @@ const (
 	traceMode
 	threadCreateMode
 	goroutineMode
+	clockMode
 )
 
 // Profile represents an active profiling session.
@@ -122,6 +125,10 @@ func ThreadcreationProfile(p *Profile) { p.mode = threadCreateMode }
 // It disables any previous profiling settings.
 func GoroutineProfile(p *Profile) { p.mode = goroutineMode }
 
+// ClockProfile enables wall clock (fgprof) profiling.
+// It disables any previous profiling settings.
+func ClockProfile(p *Profile) { p.mode = clockMode }
+
 // ProfilePath controls the base path where various profiling
 // files are written. If blank, the base path will be generated
 // by ioutil.TempDir.
@@ -287,6 +294,20 @@ func Start(options ...func(*Profile)) interface {
 			f.Close()
 			logf("profile: goroutine profiling disabled, %s", fn)
 		}
+
+	case clockMode:
+		fn := filepath.Join(path, "clock.pprof")
+		f, err := os.Create(fn)
+		if err != nil {
+			log.Fatalf("profile: could not create clock profile %q: %v", fn, err)
+		}
+		logf("profile: clock profiling enabled, %s", fn)
+		stop := fgprof.Start(f, fgprof.FormatPprof)
+		prof.closer = func() {
+			stop()
+			f.Close()
+			logf("profile: clock profiling disabled, %s", fn)
+		}
 	}
 
 	if !prof.noShutdownHook {
diff --git a/profile_test.go b/profile_test.go
index e33012c..b4cd651 100644
--- a/profile_test.go
+++ b/profile_test.go
@@ -122,6 +122,22 @@ func main() {
 			Stderr("profile: mutex profiling enabled"),
 			NoErr,
 		},
+	}, {
+		name: "clock profile",
+		code: `
+package main
+
+import "github.com/pkg/profile"
+
+func main() {
+	defer profile.Start(profile.ClockProfile).Stop()
+}
+`,
+		checks: []checkFn{
+			NoStdout,
+			Stderr("profile: clock profiling enabled"),
+			NoErr,
+		},
 	}, {
 		name: "profile path",
 		code: `