misc/cgo/testcarchive, misc/cgo/testcshared: sleep instead of sched_yield

Apparently when GOMAXPROCS == 1 a simple sched_yield in a tight loop is
not necessarily sufficient to permit a signal handler to run. Instead,
sleep for 1/1000 of a second.

Fixes #16649.

Change-Id: I83910144228556e742b7a92a441732ef61aa49d9
Reviewed-on: https://go-review.googlesource.com/33239
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

misc/cgo/testcarchive/main2.c

@@ -112,6 +112,7 @@ int main(int argc, char** argv) {
 	int verbose;
 	sigset_t mask;
 	int i;
+	struct timespec ts;
 
 	verbose = argc > 1;
 	setvbuf(stdout, NULL, _IONBF, 0);
@@ -161,9 +162,9 @@ int main(int argc, char** argv) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (!sigioSeen) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");

misc/cgo/testcarchive/main3.c

@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <sched.h>
 
 #include "libgo3.h"
@@ -28,6 +29,7 @@ int main(int argc, char** argv) {
 	int verbose;
 	struct sigaction sa;
 	int i;
+	struct timespec ts;
 
 	verbose = argc > 2;
 	setvbuf(stdout, NULL, _IONBF, 0);
@@ -64,9 +66,9 @@ int main(int argc, char** argv) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (!sigioSeen) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");
@@ -138,9 +140,9 @@ int main(int argc, char** argv) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (!sigioSeen) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");

misc/cgo/testcarchive/main4.c

@@ -8,6 +8,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <sched.h>
 #include <pthread.h>
 
@@ -48,6 +49,7 @@ static void* thread1(void* arg __attribute__ ((unused))) {
 	stack_t ss;
 	int i;
 	stack_t nss;
+	struct timespec ts;
 
 	// Set up an alternate signal stack for this thread.
 	memset(&ss, 0, sizeof ss);
@@ -73,9 +75,9 @@ static void* thread1(void* arg __attribute__ ((unused))) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (SIGIOCount() == 0) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");
@@ -105,6 +107,7 @@ static void* thread2(void* arg __attribute__ ((unused))) {
 	int i;
 	int oldcount;
 	pthread_t tid;
+	struct timespec ts;
 	stack_t nss;
 
 	// Set up an alternate signal stack for this thread.
@@ -129,9 +132,9 @@ static void* thread2(void* arg __attribute__ ((unused))) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (SIGIOCount() == oldcount) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");

misc/cgo/testcshared/main4.c

@@ -77,6 +77,7 @@ int main(int argc, char** argv) {
 	void (*fn)(void);
 	sigset_t mask;
 	int i;
+	struct timespec ts;
 
 	verbose = argc > 2;
 	setvbuf(stdout, NULL, _IONBF, 0);
@@ -166,9 +167,9 @@ int main(int argc, char** argv) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (!sigioSeen) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");

misc/cgo/testcshared/main5.c

@@ -10,6 +10,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <sched.h>
 #include <dlfcn.h>
 
@@ -31,6 +32,7 @@ int main(int argc, char** argv) {
 	void (*fn1)(void);
 	int (*sawSIGIO)(void);
 	int i;
+	struct timespec ts;
 
 	verbose = argc > 2;
 	setvbuf(stdout, NULL, _IONBF, 0);
@@ -77,9 +79,9 @@ int main(int argc, char** argv) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (!sigioSeen) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");
@@ -182,9 +184,9 @@ int main(int argc, char** argv) {
 	// Wait until the signal has been delivered.
 	i = 0;
 	while (!sigioSeen) {
-		if (sched_yield() < 0) {
-			perror("sched_yield");
-		}
+		ts.tv_sec = 0;
+		ts.tv_nsec = 1000000;
+		nanosleep(&ts, NULL);
 		i++;
 		if (i > 100000) {
 			fprintf(stderr, "looping too long waiting for signal\n");