misc/cgo/test: remove timing dependency from TestParallelSleep

Rename it TestIssue1560 since it no longer sleeps.

For #1560
Fixes #45586

Change-Id: I338eee9de43e871da142143943e9435218438e90
Reviewed-on: https://go-review.googlesource.com/c/go/+/400194
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

3 files changed, 33 insertions, 53 deletions

diff --git a/misc/cgo/test/callback_c.c b/misc/cgo/test/callback_c.c
index 8921b7306c..8ecf70f272 100644
--- a/misc/cgo/test/callback_c.c
+++ b/misc/cgo/test/callback_c.c
@@ -3,8 +3,7 @@
 // license that can be found in the LICENSE file.
 
 #include <string.h>
-#include <sys/types.h>
-#include <unistd.h>
+
 #include "_cgo_export.h"
 
 void
@@ -31,32 +30,10 @@ IntoC(void)
 	BackIntoGo();
 }
 
-#ifdef WIN32
-#include <windows.h>
-long long
-mysleep(int seconds) {
-	long long st = GetTickCount();
-	Sleep(1000 * seconds);
-	return st;
-}
-#else
-#include <sys/time.h>
-long long
-mysleep(int seconds) {
-	long long st;
-	struct timeval tv;
-	gettimeofday(&tv, NULL);
-	st = tv.tv_sec * 1000 + tv.tv_usec / 1000;
-	sleep(seconds);
-	return st;
-}
-#endif
-
-long long
-twoSleep(int n)
+void
+Issue1560InC(void)
 {
-	BackgroundSleep(n);
-	return mysleep(n);
+	Issue1560FromC();
 }
 
 void
diff --git a/misc/cgo/test/cgo_test.go b/misc/cgo/test/cgo_test.go
index 774277e10d..dee6164354 100644
--- a/misc/cgo/test/cgo_test.go
+++ b/misc/cgo/test/cgo_test.go
@@ -11,6 +11,7 @@ import "testing"
 // These wrappers are here for gotest to find.
 
 func Test1328(t *testing.T)                  { test1328(t) }
+func Test1560(t *testing.T)                  { test1560(t) }
 func Test1635(t *testing.T)                  { test1635(t) }
 func Test3250(t *testing.T)                  { test3250(t) }
 func Test3729(t *testing.T)                  { test3729(t) }
@@ -89,7 +90,6 @@ func TestLibgcc(t *testing.T)                { testLibgcc(t) }
 func TestMultipleAssign(t *testing.T)        { testMultipleAssign(t) }
 func TestNaming(t *testing.T)                { testNaming(t) }
 func TestPanicFromC(t *testing.T)            { testPanicFromC(t) }
-func TestParallelSleep(t *testing.T)         { testParallelSleep(t) }
 func TestPrintf(t *testing.T)                { testPrintf(t) }
 func TestReturnAfterGrow(t *testing.T)       { testReturnAfterGrow(t) }
 func TestReturnAfterGrowFromGo(t *testing.T) { testReturnAfterGrowFromGo(t) }
diff --git a/misc/cgo/test/testx.go b/misc/cgo/test/testx.go
index 8ec84a8b22..6a8e97ddf3 100644
--- a/misc/cgo/test/testx.go
+++ b/misc/cgo/test/testx.go
@@ -18,7 +18,6 @@ import (
 	"sync"
 	"sync/atomic"
 	"testing"
-	"time"
 	"unsafe"
 )
 
@@ -30,8 +29,7 @@ extern void doAdd(int, int);
 void IntoC(void);
 
 // issue 1560
-// mysleep returns the absolute start time in ms.
-long long mysleep(int seconds);
+extern void Issue1560InC(void);
 
 // twoSleep returns the absolute start time of the first sleep
 // in ms.
@@ -183,35 +181,40 @@ func test1328(t *testing.T) {
 }
 
 // issue 1560
+// Test that C functions and Go functions run in parallel.
 
-var sleepDone = make(chan int64)
+var (
+	issue1560 int32
 
-// parallelSleep returns the absolute difference between the start time
-// of the two sleeps.
-func parallelSleep(n int) int64 {
-	t := int64(C.twoSleep(C.int(n))) - <-sleepDone
-	if t < 0 {
-		return -t
+	issue1560Ch = make(chan bool, 2)
+)
+
+//export Issue1560FromC
+func Issue1560FromC() {
+	for atomic.LoadInt32(&issue1560) != 1 {
+		runtime.Gosched()
+	}
+	atomic.AddInt32(&issue1560, 1)
+	for atomic.LoadInt32(&issue1560) != 3 {
+		runtime.Gosched()
 	}
-	return t
+	issue1560Ch <- true
 }
 
-//export BackgroundSleep
-func BackgroundSleep(n int32) {
-	go func() {
-		sleepDone <- int64(C.mysleep(C.int(n)))
-	}()
+func Issue1560FromGo() {
+	atomic.AddInt32(&issue1560, 1)
+	for atomic.LoadInt32(&issue1560) != 2 {
+		runtime.Gosched()
+	}
+	atomic.AddInt32(&issue1560, 1)
+	issue1560Ch <- true
 }
 
-func testParallelSleep(t *testing.T) {
-	sleepSec := 1
-	dt := time.Duration(parallelSleep(sleepSec)) * time.Millisecond
-	t.Logf("difference in start time for two sleep(%d) is %v", sleepSec, dt)
-	// bug used to run sleeps in serial, producing a 2*sleepSec-second delay.
-	// we detect if the start times of those sleeps are > 0.5*sleepSec-second.
-	if dt >= time.Duration(sleepSec)*time.Second/2 {
-		t.Fatalf("parallel %d-second sleeps slept for %f seconds", sleepSec, dt.Seconds())
-	}
+func test1560(t *testing.T) {
+	go Issue1560FromGo()
+	go C.Issue1560InC()
+	<-issue1560Ch
+	<-issue1560Ch
 }
 
 // issue 2462