runtime: cpu profiling support

R=r
CC=golang-dev
https://golang.org/cl/4306043

src/pkg/runtime/Makefile

@@ -53,6 +53,7 @@ OFILES=\
 	cgocall.$O\
 	chan.$O\
 	closure.$O\
+	cpuprof.$O\
 	float.$O\
 	complex.$O\
 	hashmap.$O\

src/pkg/runtime/amd64/traceback.c

@@ -18,8 +18,8 @@ void runtime·morestack(void);
 // as well as the runtime.Callers function (pcbuf != nil).
 // A little clunky to merge the two but avoids duplicating
 // the code and all its subtlety.
-static int32
-gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 max)
+int32
+runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *g, int32 skip, uintptr *pcbuf, int32 max)
 {
 	byte *p;
 	int32 i, n, iter, sawnewstack;
@@ -28,6 +28,7 @@ gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 max)
 	Stktop *stk;
 	Func *f;
 
+	USED(lr0);
 	pc = (uintptr)pc0;
 	lr = 0;
 	fp = nil;
@@ -199,7 +200,7 @@ gentraceback(byte *pc0, byte *sp, G *g, int32 skip, uintptr *pcbuf, int32 max)
 void
 runtime·traceback(byte *pc0, byte *sp, byte*, G *g)
 {
-	gentraceback(pc0, sp, g, 0, nil, 100);
+	runtime·gentraceback(pc0, sp, nil, g, 0, nil, 100);
 }
 
 int32
@@ -211,7 +212,7 @@ runtime·callers(int32 skip, uintptr *pcbuf, int32 m)
 	sp = (byte*)&skip;
 	pc = runtime·getcallerpc(&skip);
 
-	return gentraceback(pc, sp, g, skip, pcbuf, m);
+	return runtime·gentraceback(pc, sp, nil, g, skip, pcbuf, m);
 }
 
 static uintptr

src/pkg/runtime/arm/traceback.c

@@ -15,7 +15,7 @@ void _divu(void);
 void _modu(void);
 
 static int32
-gentraceback(byte *pc0, byte *sp, byte *lr0, G *g, int32 skip, uintptr *pcbuf, int32 max)
+runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *g, int32 skip, uintptr *pcbuf, int32 max)
 {
 	int32 i, n, iter;
 	uintptr pc, lr, tracepc, x;
@@ -189,11 +189,10 @@ gentraceback(byte *pc0, byte *sp, byte *lr0, G *g, int32 skip, uintptr *pcbuf, i
 	return n;		
 }
 
-
 void
 runtime·traceback(byte *pc0, byte *sp, byte *lr, G *g)
 {
-	gentraceback(pc0, sp, lr, g, 0, nil, 100);
+	runtime·gentraceback(pc0, sp, lr, g, 0, nil, 100);
 }
 
 // func caller(n int) (pc uintptr, file string, line int, ok bool)
@@ -205,5 +204,5 @@ runtime·callers(int32 skip, uintptr *pcbuf, int32 m)
 	sp = runtime·getcallersp(&skip);
 	pc = runtime·getcallerpc(&skip);
 
-	return gentraceback(pc, sp, 0, g, skip, pcbuf, m);
+	return runtime·gentraceback(pc, sp, 0, g, skip, pcbuf, m);
 }

src/pkg/runtime/darwin/386/signal.c

@@ -46,6 +46,11 @@ runtime·sighandler(int32 sig, Siginfo *info, void *context, G *gp)
 	mc = uc->uc_mcontext;
 	r = &mc->ss;
 
+	if(sig == SIGPROF) {
+		runtime·sigprof((uint8*)r->eip, (uint8*)r->esp, nil, gp);
+		return;
+	}
+
 	if(gp != nil && (runtime·sigtab[sig].flags & SigPanic)) {
 		// Work around Leopard bug that doesn't set FPE_INTDIV.
 		// Look at instruction to see if it is a divide.
@@ -126,31 +131,58 @@ runtime·signalstack(byte *p, int32 n)
 	runtime·sigaltstack(&st, nil);
 }
 
+static void
+sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
+{
+	Sigaction sa;
+
+	runtime·memclr((byte*)&sa, sizeof sa);
+	sa.sa_flags = SA_SIGINFO|SA_ONSTACK;
+	if(restart)
+		sa.sa_flags |= SA_RESTART;
+	sa.sa_mask = ~0U;
+	sa.sa_tramp = (uintptr)runtime·sigtramp;	// runtime·sigtramp's job is to call into real handler
+	sa.__sigaction_u.__sa_sigaction = (uintptr)fn;
+	runtime·sigaction(i, &sa, nil);
+}
+
 void
 runtime·initsig(int32 queue)
 {
 	int32 i;
-	static Sigaction sa;
+	void *fn;
 
 	runtime·siginit();
 
-	sa.sa_flags |= SA_SIGINFO|SA_ONSTACK;
-	sa.sa_mask = 0xFFFFFFFFU;
-	sa.sa_tramp = runtime·sigtramp;	// runtime·sigtramp's job is to call into real handler
 	for(i = 0; i<NSIG; i++) {
 		if(runtime·sigtab[i].flags) {
 			if((runtime·sigtab[i].flags & SigQueue) != queue)
 				continue;
-			if(runtime·sigtab[i].flags & (SigCatch | SigQueue)) {
-				sa.__sigaction_u.__sa_sigaction = runtime·sighandler;
-			} else {
-				sa.__sigaction_u.__sa_sigaction = runtime·sigignore;
-			}
-			if(runtime·sigtab[i].flags & SigRestart)
-				sa.sa_flags |= SA_RESTART;
+			if(runtime·sigtab[i].flags & (SigCatch | SigQueue))
+				fn = runtime·sighandler;
 			else
-				sa.sa_flags &= ~SA_RESTART;
-			runtime·sigaction(i, &sa, nil);
+				fn = runtime·sigignore;
+			sigaction(i, fn, (runtime·sigtab[i].flags & SigRestart) != 0);
 		}
 	}
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	Sigaction sa;
+	Itimerval it;
+	
+	runtime·memclr((byte*)&it, sizeof it);
+	if(hz == 0) {
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+		sigaction(SIGPROF, SIG_IGN, true);
+	} else {
+		sigaction(SIGPROF, runtime·sighandler, true);
+		it.it_interval.tv_sec = 0;
+		it.it_interval.tv_usec = 1000000 / hz;
+		it.it_value = it.it_interval;
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+	}
+	m->profilehz = hz;
+}

src/pkg/runtime/darwin/amd64/signal.c

@@ -54,6 +54,11 @@ runtime·sighandler(int32 sig, Siginfo *info, void *context, G *gp)
 	mc = uc->uc_mcontext;
 	r = &mc->ss;
 
+	if(sig == SIGPROF) {
+		runtime·sigprof((uint8*)r->rip, (uint8*)r->rsp, nil, gp);
+		return;
+	}
+
 	if(gp != nil && (runtime·sigtab[sig].flags & SigPanic)) {
 		// Work around Leopard bug that doesn't set FPE_INTDIV.
 		// Look at instruction to see if it is a divide.
@@ -136,31 +141,58 @@ runtime·signalstack(byte *p, int32 n)
 	runtime·sigaltstack(&st, nil);
 }
 
+static void
+sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
+{
+	Sigaction sa;
+
+	runtime·memclr((byte*)&sa, sizeof sa);
+	sa.sa_flags = SA_SIGINFO|SA_ONSTACK;
+	if(restart)
+		sa.sa_flags |= SA_RESTART;
+	sa.sa_mask = ~0ULL;
+	sa.sa_tramp = (uintptr)runtime·sigtramp;	// runtime·sigtramp's job is to call into real handler
+	sa.__sigaction_u.__sa_sigaction = (uintptr)fn;
+	runtime·sigaction(i, &sa, nil);
+}
+
 void
 runtime·initsig(int32 queue)
 {
 	int32 i;
-	static Sigaction sa;
+	void *fn;
 
 	runtime·siginit();
 
-	sa.sa_flags |= SA_SIGINFO|SA_ONSTACK;
-	sa.sa_mask = 0xFFFFFFFFU;
-	sa.sa_tramp = runtime·sigtramp;	// runtime·sigtramp's job is to call into real handler
 	for(i = 0; i<NSIG; i++) {
 		if(runtime·sigtab[i].flags) {
 			if((runtime·sigtab[i].flags & SigQueue) != queue)
 				continue;
-			if(runtime·sigtab[i].flags & (SigCatch | SigQueue)) {
-				sa.__sigaction_u.__sa_sigaction = runtime·sighandler;
-			} else {
-				sa.__sigaction_u.__sa_sigaction = runtime·sigignore;
-			}
-			if(runtime·sigtab[i].flags & SigRestart)
-				sa.sa_flags |= SA_RESTART;
+			if(runtime·sigtab[i].flags & (SigCatch | SigQueue))
+				fn = runtime·sighandler;
 			else
-				sa.sa_flags &= ~SA_RESTART;
-			runtime·sigaction(i, &sa, nil);
+				fn = runtime·sigignore;
+			sigaction(i, fn, (runtime·sigtab[i].flags & SigRestart) != 0);
 		}
 	}
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	Sigaction sa;
+	Itimerval it;
+	
+	runtime·memclr((byte*)&it, sizeof it);
+	if(hz == 0) {
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+		sigaction(SIGPROF, SIG_IGN, true);
+	} else {
+		sigaction(SIGPROF, runtime·sighandler, true);
+		it.it_interval.tv_sec = 0;
+		it.it_interval.tv_usec = 1000000 / hz;
+		it.it_value = it.it_interval;
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+	}
+	m->profilehz = hz;
+}

src/pkg/runtime/debug.go

@@ -92,4 +92,24 @@ func (r *MemProfileRecord) Stack() []uintptr {
 // where r.AllocBytes > 0 but r.AllocBytes == r.FreeBytes.
 // These are sites where memory was allocated, but it has all
 // been released back to the runtime.
+// Most clients should use the runtime/pprof package or
+// the testing package's -test.memprofile flag instead
+// of calling MemProfile directly.
 func MemProfile(p []MemProfileRecord, inuseZero bool) (n int, ok bool)
+
+// CPUProfile returns the next chunk of binary CPU profiling stack trace data,
+// blocking until data is available.  If profiling is turned off and all the profile
+// data accumulated while it was on has been returned, CPUProfile returns nil.
+// The caller must save the returned data before calling CPUProfile again.
+// Most clients should use the runtime/pprof package or
+// the testing package's -test.cpuprofile flag instead of calling
+// CPUProfile directly.
+func CPUProfile() []byte
+
+// SetCPUProfileRate sets the CPU profiling rate to hz samples per second.
+// If hz <= 0, SetCPUProfileRate turns off profiling.
+// If the profiler is on, the rate cannot be changed without first turning it off.
+// Most clients should use the runtime/pprof package or
+// the testing package's -test.cpuprofile flag instead of calling
+// SetCPUProfileRate directly.
+func SetCPUProfileRate(hz int)

src/pkg/runtime/freebsd/386/signal.c

@@ -54,6 +54,11 @@ runtime·sighandler(int32 sig, Siginfo *info, void *context, G *gp)
 	uc = context;
 	r = &uc->uc_mcontext;
 
+	if(sig == SIGPROF) {
+		runtime·sigprof((uint8*)r->mc_eip, (uint8*)r->mc_esp, nil, gp);
+		return;
+	}
+
 	if(gp != nil && (runtime·sigtab[sig].flags & SigPanic)) {
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
@@ -122,32 +127,57 @@ runtime·signalstack(byte *p, int32 n)
 	runtime·sigaltstack(&st, nil);
 }
 
+static void
+sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
+{
+	Sigaction sa;
+
+	runtime·memclr((byte*)&sa, sizeof sa);
+	sa.sa_flags = SA_SIGINFO|SA_ONSTACK;
+	if(restart)
+		sa.sa_flags |= SA_RESTART;
+	sa.sa_mask = ~0ULL;
+	sa.__sigaction_u.__sa_sigaction = (uintptr)fn;
+	runtime·sigaction(i, &sa, nil);
+}
+
 void
 runtime·initsig(int32 queue)
 {
-	static Sigaction sa;
+	int32 i;
+	void *fn;
 
 	runtime·siginit();
 
-	int32 i;
-	sa.sa_flags |= SA_ONSTACK | SA_SIGINFO;
-	sa.sa_mask = ~0x0ull;
-	
-	for(i = 0; i < NSIG; i++) {
+	for(i = 0; i<NSIG; i++) {
 		if(runtime·sigtab[i].flags) {
 			if((runtime·sigtab[i].flags & SigQueue) != queue)
 				continue;
 			if(runtime·sigtab[i].flags & (SigCatch | SigQueue))
-				sa.__sigaction_u.__sa_sigaction = (void*) runtime·sigtramp;
+				fn = runtime·sighandler;
 			else
-				sa.__sigaction_u.__sa_sigaction = (void*) runtime·sigignore;
-
-			if(runtime·sigtab[i].flags & SigRestart)
-				sa.sa_flags |= SA_RESTART;
-			else
-				sa.sa_flags &= ~SA_RESTART;
-
-			runtime·sigaction(i, &sa, nil);
+				fn = runtime·sigignore;
+			sigaction(i, fn, (runtime·sigtab[i].flags & SigRestart) != 0);
 		}
 	}
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	Sigaction sa;
+	Itimerval it;
+	
+	runtime·memclr((byte*)&it, sizeof it);
+	if(hz == 0) {
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+		sigaction(SIGPROF, SIG_IGN, true);
+	} else {
+		sigaction(SIGPROF, runtime·sighandler, true);
+		it.it_interval.tv_sec = 0;
+		it.it_interval.tv_usec = 1000000 / hz;
+		it.it_value = it.it_interval;
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+	}
+	m->profilehz = hz;
+}

src/pkg/runtime/freebsd/amd64/signal.c

@@ -62,6 +62,11 @@ runtime·sighandler(int32 sig, Siginfo *info, void *context, G *gp)
 	uc = context;
 	r = &uc->uc_mcontext;
 
+	if(sig == SIGPROF) {
+		runtime·sigprof((uint8*)r->mc_rip, (uint8*)r->mc_rsp, nil, gp);
+		return;
+	}
+
 	if(gp != nil && (runtime·sigtab[sig].flags & SigPanic)) {
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
@@ -130,32 +135,57 @@ runtime·signalstack(byte *p, int32 n)
 	runtime·sigaltstack(&st, nil);
 }
 
+static void
+sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
+{
+	Sigaction sa;
+
+	runtime·memclr((byte*)&sa, sizeof sa);
+	sa.sa_flags = SA_SIGINFO|SA_ONSTACK;
+	if(restart)
+		sa.sa_flags |= SA_RESTART;
+	sa.sa_mask = ~0ULL;
+	sa.__sigaction_u.__sa_sigaction = (uintptr)fn;
+	runtime·sigaction(i, &sa, nil);
+}
+
 void
 runtime·initsig(int32 queue)
 {
-	static Sigaction sa;
+	int32 i;
+	void *fn;
 
 	runtime·siginit();
 
-	int32 i;
-	sa.sa_flags |= SA_ONSTACK | SA_SIGINFO;
-	sa.sa_mask = ~0x0ull;
-	
-	for(i = 0; i < NSIG; i++) {
+	for(i = 0; i<NSIG; i++) {
 		if(runtime·sigtab[i].flags) {
 			if((runtime·sigtab[i].flags & SigQueue) != queue)
 				continue;
 			if(runtime·sigtab[i].flags & (SigCatch | SigQueue))
-				sa.__sigaction_u.__sa_sigaction = (void*) runtime·sigtramp;
+				fn = runtime·sighandler;
 			else
-				sa.__sigaction_u.__sa_sigaction = (void*) runtime·sigignore;
-
-			if(runtime·sigtab[i].flags & SigRestart)
-				sa.sa_flags |= SA_RESTART;
-			else
-				sa.sa_flags &= ~SA_RESTART;
-
-			runtime·sigaction(i, &sa, nil);
+				fn = runtime·sigignore;
+			sigaction(i, fn, (runtime·sigtab[i].flags & SigRestart) != 0);
 		}
 	}
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	Sigaction sa;
+	Itimerval it;
+	
+	runtime·memclr((byte*)&it, sizeof it);
+	if(hz == 0) {
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+		sigaction(SIGPROF, SIG_IGN, true);
+	} else {
+		sigaction(SIGPROF, runtime·sighandler, true);
+		it.it_interval.tv_sec = 0;
+		it.it_interval.tv_usec = 1000000 / hz;
+		it.it_value = it.it_interval;
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+	}
+	m->profilehz = hz;
+}

src/pkg/runtime/linux/386/signal.c

@@ -51,6 +51,11 @@ runtime·sighandler(int32 sig, Siginfo *info, void *context, G *gp)
 	uc = context;
 	r = &uc->uc_mcontext;
 
+	if(sig == SIGPROF) {
+		runtime·sigprof((uint8*)r->eip, (uint8*)r->esp, nil, gp);
+		return;
+	}
+
 	if(gp != nil && (runtime·sigtab[sig].flags & SigPanic)) {
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
@@ -114,30 +119,59 @@ runtime·signalstack(byte *p, int32 n)
 	runtime·sigaltstack(&st, nil);
 }
 
+static void
+sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
+{
+	Sigaction sa;
+
+	runtime·memclr((byte*)&sa, sizeof sa);
+	sa.sa_flags = SA_ONSTACK | SA_SIGINFO | SA_RESTORER;
+	if(restart)
+		sa.sa_flags |= SA_RESTART;
+	sa.sa_mask = ~0ULL;
+	sa.sa_restorer = (void*)runtime·sigreturn;
+	if(fn == runtime·sighandler)
+		fn = (void*)runtime·sigtramp;
+	sa.k_sa_handler = fn;
+	runtime·rt_sigaction(i, &sa, nil, 8);
+}
+
 void
 runtime·initsig(int32 queue)
 {
-	static Sigaction sa;
+	int32 i;
+	void *fn;
 
 	runtime·siginit();
 
-	int32 i;
-	sa.sa_flags = SA_ONSTACK | SA_SIGINFO | SA_RESTORER;
-	sa.sa_mask = 0xFFFFFFFFFFFFFFFFULL;
-	sa.sa_restorer = (void*)runtime·sigreturn;
 	for(i = 0; i<NSIG; i++) {
 		if(runtime·sigtab[i].flags) {
 			if((runtime·sigtab[i].flags & SigQueue) != queue)
 				continue;
 			if(runtime·sigtab[i].flags & (SigCatch | SigQueue))
-				sa.k_sa_handler = (void*)runtime·sigtramp;
+				fn = runtime·sighandler;
 			else
-				sa.k_sa_handler = (void*)runtime·sigignore;
-			if(runtime·sigtab[i].flags & SigRestart)
-				sa.sa_flags |= SA_RESTART;
-			else
-				sa.sa_flags &= ~SA_RESTART;
-			runtime·rt_sigaction(i, &sa, nil, 8);
+				fn = runtime·sigignore;
+			sigaction(i, fn, (runtime·sigtab[i].flags & SigRestart) != 0);
 		}
 	}
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	Itimerval it;
+	
+	runtime·memclr((byte*)&it, sizeof it);
+	if(hz == 0) {
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+		sigaction(SIGPROF, SIG_IGN, true);
+	} else {
+		sigaction(SIGPROF, runtime·sighandler, true);
+		it.it_interval.tv_sec = 0;
+		it.it_interval.tv_usec = 1000000 / hz;
+		it.it_value = it.it_interval;
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+	}
+	m->profilehz = hz;
+}

src/pkg/runtime/linux/amd64/signal.c

@@ -61,6 +61,11 @@ runtime·sighandler(int32 sig, Siginfo *info, void *context, G *gp)
 	mc = &uc->uc_mcontext;
 	r = (Sigcontext*)mc;	// same layout, more conveient names
 
+	if(sig == SIGPROF) {
+		runtime·sigprof((uint8*)r->rip, (uint8*)r->rsp, nil, gp);
+		return;
+	}
+
 	if(gp != nil && (runtime·sigtab[sig].flags & SigPanic)) {
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
@@ -124,30 +129,59 @@ runtime·signalstack(byte *p, int32 n)
 	runtime·sigaltstack(&st, nil);
 }
 
+static void
+sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
+{
+	Sigaction sa;
+
+	runtime·memclr((byte*)&sa, sizeof sa);
+	sa.sa_flags = SA_ONSTACK | SA_SIGINFO | SA_RESTORER;
+	if(restart)
+		sa.sa_flags |= SA_RESTART;
+	sa.sa_mask = ~0ULL;
+	sa.sa_restorer = (void*)runtime·sigreturn;
+	if(fn == runtime·sighandler)
+		fn = (void*)runtime·sigtramp;
+	sa.sa_handler = fn;
+	runtime·rt_sigaction(i, &sa, nil, 8);
+}
+
 void
 runtime·initsig(int32 queue)
 {
-	static Sigaction sa;
+	int32 i;
+	void *fn;
 
 	runtime·siginit();
 
-	int32 i;
-	sa.sa_flags = SA_ONSTACK | SA_SIGINFO | SA_RESTORER;
-	sa.sa_mask = 0xFFFFFFFFFFFFFFFFULL;
-	sa.sa_restorer = (void*)runtime·sigreturn;
 	for(i = 0; i<NSIG; i++) {
 		if(runtime·sigtab[i].flags) {
 			if((runtime·sigtab[i].flags & SigQueue) != queue)
 				continue;
 			if(runtime·sigtab[i].flags & (SigCatch | SigQueue))
-				sa.sa_handler = (void*)runtime·sigtramp;
+				fn = runtime·sighandler;
 			else
-				sa.sa_handler = (void*)runtime·sigignore;
-			if(runtime·sigtab[i].flags & SigRestart)
-				sa.sa_flags |= SA_RESTART;
-			else
-				sa.sa_flags &= ~SA_RESTART;
-			runtime·rt_sigaction(i, &sa, nil, 8);
+				fn = runtime·sigignore;
+			sigaction(i, fn, (runtime·sigtab[i].flags & SigRestart) != 0);
 		}
 	}
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	Itimerval it;
+	
+	runtime·memclr((byte*)&it, sizeof it);
+	if(hz == 0) {
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+		sigaction(SIGPROF, SIG_IGN, true);
+	} else {
+		sigaction(SIGPROF, runtime·sighandler, true);
+		it.it_interval.tv_sec = 0;
+		it.it_interval.tv_usec = 1000000 / hz;
+		it.it_value = it.it_interval;
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+	}
+	m->profilehz = hz;
+}

src/pkg/runtime/linux/arm/signal.c

@@ -58,6 +58,11 @@ runtime·sighandler(int32 sig, Siginfo *info, void *context, G *gp)
 	uc = context;
 	r = &uc->uc_mcontext;
 
+	if(sig == SIGPROF) {
+		runtime·sigprof((uint8*)r->arm_pc, (uint8*)r->arm_sp, (uint8*)r->arm_lr, gp);
+		return;
+	}
+
 	if(gp != nil && (runtime·sigtab[sig].flags & SigPanic)) {
 		// Make it look like a call to the signal func.
 		// Have to pass arguments out of band since
@@ -119,31 +124,58 @@ runtime·signalstack(byte *p, int32 n)
 	runtime·sigaltstack(&st, nil);
 }
 
+static void
+sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
+{
+	Sigaction sa;
+
+	runtime·memclr((byte*)&sa, sizeof sa);
+	sa.sa_flags = SA_ONSTACK | SA_SIGINFO | SA_RESTORER;
+	if(restart)
+		sa.sa_flags |= SA_RESTART;
+	sa.sa_mask = ~0ULL;
+	sa.sa_restorer = (void*)runtime·sigreturn;
+	sa.k_sa_handler = fn;
+	runtime·rt_sigaction(i, &sa, nil, 8);
+}
+
 void
 runtime·initsig(int32 queue)
 {
-	static Sigaction sa;
+	int32 i;
+	void *fn;
 
 	runtime·siginit();
 
-	int32 i;
-	sa.sa_flags = SA_ONSTACK | SA_SIGINFO | SA_RESTORER;
-	sa.sa_mask.sig[0] = 0xFFFFFFFF;
-	sa.sa_mask.sig[1] = 0xFFFFFFFF;
-	sa.sa_restorer = (void*)runtime·sigreturn;
 	for(i = 0; i<NSIG; i++) {
 		if(runtime·sigtab[i].flags) {
 			if((runtime·sigtab[i].flags & SigQueue) != queue)
 				continue;
 			if(runtime·sigtab[i].flags & (SigCatch | SigQueue))
-				sa.sa_handler = (void*)runtime·sigtramp;
+				fn = runtime·sighandler;
 			else
-				sa.sa_handler = (void*)runtime·sigignore;
-			if(runtime·sigtab[i].flags & SigRestart)
-				sa.sa_flags |= SA_RESTART;
-			else
-				sa.sa_flags &= ~SA_RESTART;
-			runtime·rt_sigaction(i, &sa, nil, 8);
+				fn = runtime·sigignore;
+			sigaction(i, fn, (runtime·sigtab[i].flags & SigRestart) != 0);
 		}
 	}
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	Sigaction sa;
+	Itimerval it;
+	
+	runtime·memclr((byte*)&it, sizeof it);
+	if(hz == 0) {
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+		sigaction(SIGPROF, SIG_IGN, true);
+	} else {
+		sigaction(SIGPROF, runtime·sighandler, true);
+		it.it_interval.tv_sec = 0;
+		it.it_interval.tv_usec = 1000000 / hz;
+		it.it_value = it.it_interval;
+		runtime·setitimer(ITIMER_PROF, &it, nil);
+	}
+	m->profilehz = hz;
+}

src/pkg/runtime/plan9/386/signal.c

@@ -14,3 +14,11 @@ runtime·signame(int32)
 {
 	return runtime·emptystring;
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	// TODO: Enable profiling interrupts.
+	
+	m->profilehz = hz;
+}

src/pkg/runtime/proc.c

@@ -70,6 +70,7 @@ struct Sched {
 	int32 msyscall;	// number of ms in system calls
 
 	int32 predawn;	// running initialization, don't run new gs.
+	int32 profilehz;	// cpu profiling rate
 
 	Note	stopped;	// one g can wait here for ms to stop
 	int32 waitstop;	// after setting this flag
@@ -96,9 +97,6 @@ static void matchmg(void);	// match ms to gs
 static void readylocked(G*);	// ready, but sched is locked
 static void mnextg(M*, G*);
 
-// Scheduler loop.
-static void scheduler(void);
-
 // The bootstrap sequence is:
 //
 //	call osinit
@@ -529,6 +527,8 @@ matchmg(void)
 static void
 schedule(G *gp)
 {
+	int32 hz;
+
 	schedlock();
 	if(gp != nil) {
 		if(runtime·sched.predawn)
@@ -574,6 +574,12 @@ schedule(G *gp)
 	gp->status = Grunning;
 	m->curg = gp;
 	gp->m = m;
+	
+	// Check whether the profiler needs to be turned on or off.
+	hz = runtime·sched.profilehz;
+	if(m->profilehz != hz)
+		runtime·resetcpuprofiler(hz);
+
 	if(gp->sched.pc == (byte*)runtime·goexit) {	// kickoff
 		runtime·gogocall(&gp->sched, (void(*)(void))gp->entry);
 	}
@@ -640,7 +646,7 @@ runtime·exitsyscall(void)
 	runtime·sched.msyscall--;
 	runtime·sched.mcpu++;
 	// Fast path - if there's room for this m, we're done.
-	if(runtime·sched.mcpu <= runtime·sched.mcpumax) {
+	if(m->profilehz == runtime·sched.profilehz && runtime·sched.mcpu <= runtime·sched.mcpumax) {
 		g->status = Grunning;
 		schedunlock();
 		return;
@@ -1251,3 +1257,57 @@ runtime·badmcall2(void)  // called from assembly
 {
 	runtime·throw("runtime: mcall function returned");
 }
+
+static struct {
+	Lock;
+	void (*fn)(uintptr*, int32);
+	int32 hz;
+	uintptr pcbuf[100];
+} prof;
+
+void
+runtime·sigprof(uint8 *pc, uint8 *sp, uint8 *lr, G *gp)
+{
+	int32 n;
+	
+	if(prof.fn == nil || prof.hz == 0)
+		return;
+	
+	runtime·lock(&prof);
+	if(prof.fn == nil) {
+		runtime·unlock(&prof);
+		return;
+	}
+	n = runtime·gentraceback(pc, sp, lr, gp, 0, prof.pcbuf, nelem(prof.pcbuf));
+	if(n > 0)
+		prof.fn(prof.pcbuf, n);
+	runtime·unlock(&prof);
+}
+
+void
+runtime·setcpuprofilerate(void (*fn)(uintptr*, int32), int32 hz)
+{
+	// Force sane arguments.
+	if(hz < 0)
+		hz = 0;
+	if(hz == 0)
+		fn = nil;
+	if(fn == nil)
+		hz = 0;
+
+	// Stop profiler on this cpu so that it is safe to lock prof.
+	// if a profiling signal came in while we had prof locked,
+	// it would deadlock.
+	runtime·resetcpuprofiler(0);
+
+	runtime·lock(&prof);
+	prof.fn = fn;
+	prof.hz = hz;
+	runtime·unlock(&prof);
+	runtime·lock(&runtime·sched);
+	runtime·sched.profilehz = hz;
+	runtime·unlock(&runtime·sched);
+	
+	if(hz != 0)
+		runtime·resetcpuprofiler(hz);
+}

src/pkg/runtime/runtime.h

@@ -225,6 +225,7 @@ struct	M
 	int32	nomemprof;
 	int32	waitnextg;
 	int32	dying;
+	int32	profilehz;
 	Note	havenextg;
 	G*	nextg;
 	M*	alllink;	// on allm
@@ -453,9 +454,13 @@ void	runtime·siginit(void);
 bool	runtime·sigsend(int32 sig);
 void	runtime·gettime(int64*, int32*);
 int32	runtime·callers(int32, uintptr*, int32);
+int32	runtime·gentraceback(byte*, byte*, byte*, G*, int32, uintptr*, int32);
 int64	runtime·nanotime(void);
 void	runtime·dopanic(int32);
 void	runtime·startpanic(void);
+void	runtime·sigprof(uint8 *pc, uint8 *sp, uint8 *lr, G *gp);
+void	runtime·resetcpuprofiler(int32);
+void	runtime·setcpuprofilerate(void(*)(uintptr*, int32), int32);
 
 #pragma	varargck	argpos	runtime·printf	1
 #pragma	varargck	type	"d"	int32

src/pkg/runtime/windows/386/signal.c

@@ -88,3 +88,11 @@ runtime·sighandler(ExceptionRecord *info, void *frame, Context *r)
 	runtime·exit(2);
 	return 0;
 }
+
+void
+runtime·resetcpuprofiler(int32 hz)
+{
+	// TODO: Enable profiling interrupts.
+	
+	m->profilehz = hz;
+}