Add the -profile option

README.md

@@ -133,6 +133,8 @@ Only valid on SDL mode
         emulate a green phosphor monitor instead of a NTSC color TV. Use F6 to toggle.
   -panicss
         panic if a not implemented softswitch is used
+  -profile
+        generate profile trace to analyse with pprof
   -rom string
         main rom file (default "<internal>/Apple2_Plus.rom")
   -saturnCardSlot int

apple2.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/ivanizag/apple2/core6502"
+	"github.com/pkg/profile"
 )
 
 // Apple2 represents all the components and state of the emulated machine
@@ -25,6 +26,7 @@ type Apple2 struct {
 	isColor             bool
 	fastMode            bool
 	fastRequestsCounter int
+	profile             bool
 }
 
 const (
@@ -37,6 +39,12 @@ const maxWaitDuration = 100 * time.Millisecond
 
 // Run starts the Apple2 emulation
 func (a *Apple2) Run() {
+	if a.profile {
+		// See the log with:
+		//    go tool pprof --pdf ~/go/bin/apple2sdl /tmp/profile329536248/cpu.pprof > profile.pdf
+		defer profile.Start().Stop()
+	}
+
 	// Start the processor
 	a.cpu.Reset()
 	referenceTime := time.Now()
@@ -50,6 +58,9 @@ func (a *Apple2) Run() {
 		for commandsPending {
 			select {
 			case command := <-a.commandChannel:
+				if command == CommandKill {
+					return
+				}
 				a.executeCommand(command)
 			default:
 				commandsPending = false
@@ -73,6 +84,10 @@ func (a *Apple2) Run() {
 	}
 }
 
+func (a *Apple2) setProfile(value bool) {
+	a.profile = value
+}
+
 const (
 	// CommandToggleSpeed toggles cpu speed between full speed and actual Apple II speed
 	CommandToggleSpeed = iota + 1
@@ -88,6 +103,8 @@ const (
 	CommandNextCharGenPage
 	// CommandToggleCPUTrace toggle tracing of CPU execution
 	CommandToggleCPUTrace
+	// CommandKill stops the cpu execution loop
+	CommandKill
 )
 
 // SendCommand enqueues a command to the emulator thread

apple2main.go

@@ -86,6 +86,11 @@ func MainApple() *Apple2 {
 		false,
 		"setup a Base64A clone",
 	)
+	profile := flag.Bool(
+		"profile",
+		false,
+		"generate profile trace to analyse with pprof",
+	)
 	flag.Parse()
 
 	a := NewApple2(*cpuClock, !*mono, *fastDisk)
@@ -93,6 +98,7 @@ func MainApple() *Apple2 {
 	a.cpu.SetTrace(*traceCPU)
 	a.io.setTrace(*traceSS)
 	a.io.setPanicNotImplemented(*panicSS)
+	a.setProfile(*profile)
 
 	if *charRomFile != "" {
 		cg, err := NewCharacterGenerator(*charRomFile)