diff --git a/test/chan/nonblock.go b/test/chan/nonblock.go
index 36582b9656..2b61ec9dbb 100644
--- a/test/chan/nonblock.go
+++ b/test/chan/nonblock.go
@@ -9,40 +9,55 @@
 
 package main
 
-func pause() {
-	for i:=0; i<100; i++ { sys.Gosched() }
-}
+import "time"
 
-func i32receiver(c chan int32) {
+func i32receiver(c chan int32, strobe chan bool) {
 	if <-c != 123 { panic("i32 value") }
+	strobe <- true
 }
 
-func i32sender(c chan int32) {
-	c <- 234
+func i32sender(c chan int32, strobe chan bool) {
+	c <- 234;
+	strobe <- true
 }
 
-func i64receiver(c chan int64) {
+func i64receiver(c chan int64, strobe chan bool) {
 	if <-c != 123456 { panic("i64 value") }
+	strobe <- true
 }
 
-func i64sender(c chan int64) {
-	c <- 234567
+func i64sender(c chan int64, strobe chan bool) {
+	c <- 234567;
+	strobe <- true
 }
 
-func breceiver(c chan bool) {
+func breceiver(c chan bool, strobe chan bool) {
 	if ! <-c { panic("b value") }
+	strobe <- true
 }
 
-func bsender(c chan bool) {
-	c <- true
+func bsender(c chan bool, strobe chan bool) {
+	c <- true;
+	strobe <- true
 }
 
-func sreceiver(c chan string) {
+func sreceiver(c chan string, strobe chan bool) {
 	if <-c != "hello" { panic("s value") }
+	strobe <- true
 }
 
-func ssender(c chan string) {
-	c <- "hello again"
+func ssender(c chan string, strobe chan bool) {
+	c <- "hello again";
+	strobe <- true
+}
+
+var ticker = time.Tick(10*1000);	// 10 us
+func sleep() {
+	<-ticker;
+	<-ticker;
+	sys.Gosched();
+	sys.Gosched();
+	sys.Gosched();
 }
 
 func main() {
@@ -52,6 +67,8 @@ func main() {
 	var s string;
 	var ok bool;
 
+	var sync = make(chan bool);
+
 	for buffer := 0; buffer < 2; buffer++ {
 		c32 := make(chan int32, buffer);
 		c64 := make(chan int64, buffer);
@@ -70,45 +87,57 @@ func main() {
 		s, ok = <-cs;
 		if ok { panic("blocked ssender") }
 
-		go i32receiver(c32);
-		pause();
+		go i32receiver(c32, sync);
+		sleep();
 		ok = c32 <- 123;
-		if !ok { panic("i32receiver") }
-		go i32sender(c32);
-		pause();
-		i32, ok = <-c32;
-		if !ok { panic("i32sender") }
-		if i32 != 234 { panic("i32sender value") }
+		if !ok { panic("i32receiver buffer=", buffer) }
+		<-sync;
 
-		go i64receiver(c64);
-		pause();
+		go i32sender(c32, sync);
+		if buffer > 0 { <-sync } else { sleep() }
+		i32, ok = <-c32;
+		if !ok { panic("i32sender buffer=", buffer) }
+		if i32 != 234 { panic("i32sender value") }
+		if buffer == 0 { <-sync }
+
+		go i64receiver(c64, sync);
+		sleep();
 		ok = c64 <- 123456;
 		if !ok { panic("i64receiver") }
-		go i64sender(c64);
-		pause();
+		<-sync;
+
+		go i64sender(c64, sync);
+		if buffer > 0 { <-sync } else { sleep() }
 		i64, ok = <-c64;
 		if !ok { panic("i64sender") }
 		if i64 != 234567 { panic("i64sender value") }
+		if buffer == 0 { <-sync }
 
-		go breceiver(cb);
-		pause();
+		go breceiver(cb, sync);
+		sleep();
 		ok = cb <- true;
 		if !ok { panic("breceiver") }
-		go bsender(cb);
-		pause();
+		<-sync;
+
+		go bsender(cb, sync);
+		if buffer > 0 { <-sync } else { sleep() }
 		b, ok = <-cb;
 		if !ok { panic("bsender") }
 		if !b{ panic("bsender value") }
+		if buffer == 0 { <-sync }
 
-		go sreceiver(cs);
-		pause();
+		go sreceiver(cs, sync);
+		sleep();
 		ok = cs <- "hello";
 		if !ok { panic("sreceiver") }
-		go ssender(cs);
-		pause();
+		<-sync;
+
+		go ssender(cs, sync);
+		if buffer > 0 { <-sync } else { sleep() }
 		s, ok = <-cs;
 		if !ok { panic("ssender") }
 		if s != "hello again" { panic("ssender value") }
+		if buffer == 0 { <-sync }
 	}
 	print("PASS\n")
 }