// a non-zero byte to w, WaitForSigusr1 returns immediately with -1, -1.
func WaitForSigusr1(r, w int32, ready func(mp *M)) (int64, int64) {
	lockOSThread()
	// Make sure we can receive SIGUSR1.
	unblocksig(_SIGUSR1)

	waitForSigusr1.rdpipe = r
	waitForSigusr1.wrpipe = w

	mp := getg().m
	testSigusr1 = waitForSigusr1Callback
	ready(mp)

	// Wait for the signal. We use a pipe rather than a note

    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Finish the task by unblocking the task latch.  Then wait for the
    // listener to be called by blocking on the listener latch.

    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Finish the task by unblocking the task latch.  Then wait for the
    // listener to be called by blocking on the listener latch.

	// 	P.1 locks file A.
	// 	Q.3 locks file B.
	// 	Q.3 blocks on file A.
	// 	P.2 blocks on file B. (This is erroneously reported as a deadlock.)
	// 	P.1 unlocks file A.
	// 	Q.3 unblocks and locks file A.
	// 	Q.3 unlocks files A and B.
	// 	P.2 unblocks and locks file B.
	// 	P.2 unlocks file B.
	//
	// These spurious errors were observed in practice on AIX and Solaris in
	// cmd/go: see https://golang.org/issue/32817.
	//

	func() {
		lock.Lock()
		defer lock.Unlock()
		if wr.Set(bval) {
			t.Error("second Set() returned true")
		}
	}()
	goGetAndExpect(t, clock, counter, wr, gots, aval)
	counter.Add(1) // account for unblocking the receive on doneCh
	close(doneCh)
	time.Sleep(time.Second) // give it a chance to misbehave
	goGetAndExpect(t, clock, counter, wr, gots, aval)
}
func TestCountingWriteOnceCancel(t *testing.T) {
	oldTime := time.Now()

	// 	P.1 locks file A.
	// 	Q.3 locks file B.
	// 	Q.3 blocks on file A.
	// 	P.2 blocks on file B. (Spurious EDEADLK occurs here.)
	// 	P.1 unlocks file A.
	// 	Q.3 unblocks and locks file A.
	// 	Q.3 unlocks files A and B.
	// 	P.2 unblocks and locks file B.
	// 	P.2 unlocks file B.

	testenv.MustHaveExec(t)

	dirVar := t.Name() + "DIR"

	if dir := os.Getenv(dirVar); dir != "" {
		// Q.3 locks file B.

type Frame struct {
	PC   uint64
	Fn   string
	File string
	Line int
}

const (
	// Special P identifiers:
	FakeP    = 1000000 + iota
	TimerP   // depicts timer unblocks
	NetpollP // depicts network unblocks
	SyscallP // depicts returns from syscalls
	GCP      // depicts GC state
	ProfileP // depicts recording of CPU profile samples
)

// Event types in the trace.

  std::unique_ptr<SavedModelAPI> model =
      SavedModelAPI::Load(model_dir, *runtime, &status, &tags);

  // TODO(bmzhao): Change this to expect TF_OK when loading is implemented.
  // That unblocks writing other tests that require a TF_SavedModel*,
  // like loading a ConcreteFunction. This test at least checks that the
  // C API builds and can be minimally run.
  EXPECT_EQ(status.code(), TF_UNIMPLEMENTED);
}

	// Get reads the current value of this variable.  If this
	// variable is not set yet then this call blocks until this
	// variable gets a value.
	Get() interface{}

	// Set normally writes a value into this variable, unblocks every
	// goroutine waiting for this variable to have a value, and
	// returns true.  In the unhappy case that this variable is
	// already set, this method returns false without modifying the
	// variable's value.

  private OverflowAvoidingLockSupport() {}

  static void parkNanos(@CheckForNull Object blocker, long nanos) {
    // Even in the extremely unlikely event that a thread unblocks itself early after only 68 years,
    // this is indistinguishable from a spurious wakeup, which LockSupport allows.
    LockSupport.parkNanos(blocker, min(nanos, MAX_NANOSECONDS_THRESHOLD));
  }