Python sys.setcheckinterval() Examples

def test_is_alive_after_fork(self):
        # Try hard to trigger #18418: is_alive() could sometimes be True on
        # threads that vanished after a fork.
        old_interval = sys.getcheckinterval()

        # Make the bug more likely to manifest.
        sys.setcheckinterval(10)

        try:
            for i in range(20):
                t = threading.Thread(target=lambda: None)
                t.start()
                pid = os.fork()
                if pid == 0:
                    os._exit(1 if t.is_alive() else 0)
                else:
                    t.join()
                    pid, status = os.waitpid(pid, 0)
                    self.assertEqual(0, status)
        finally:
            sys.setcheckinterval(old_interval) 

def test_enumerate_after_join(self):
        # Try hard to trigger #1703448: a thread is still returned in
        # threading.enumerate() after it has been join()ed.
        enum = threading.enumerate
        old_interval = sys.getcheckinterval()
        try:
            for i in xrange(1, 100):
                # Try a couple times at each thread-switching interval
                # to get more interleavings.
                sys.setcheckinterval(i // 5)
                t = threading.Thread(target=lambda: None)
                t.start()
                t.join()
                l = enum()
                self.assertNotIn(t, l,
                    "#1703448 triggered after %d trials: %s" % (i, l))
        finally:
            sys.setcheckinterval(old_interval) 

def test_enumerate_after_join(self):
        # Try hard to trigger #1703448: a thread is still returned in
        # threading.enumerate() after it has been join()ed.
        enum = threading.enumerate
        old_interval = sys.getcheckinterval()
        try:
            for i in xrange(1, 100):
                # Try a couple times at each thread-switching interval
                # to get more interleavings.
                sys.setcheckinterval(i // 5)
                t = threading.Thread(target=lambda: None)
                t.start()
                t.join()
                l = enum()
                self.assertNotIn(t, l,
                    "#1703448 triggered after %d trials: %s" % (i, l))
        finally:
            sys.setcheckinterval(old_interval) 

def setup_gil():
    """
    Set extremely long GIL release interval to let threads naturally progress
    through CPU-heavy sequences without forcing the wake of another thread that
    may contend trying to run the same CPU-heavy code. For the new-style
    Ansible work, this drops runtime ~33% and involuntary context switches by
    >80%, essentially making threads cooperatively scheduled.
    """
    try:
        # Python 2.
        sys.setcheckinterval(100000)
    except AttributeError:
        pass

    try:
        # Python 3.
        sys.setswitchinterval(10)
    except AttributeError:
        pass 

def __init__(self):
        self.interval = 1/60.0
        sys.setcheckinterval(1000)
        try:
            sys.setswitchinterval(self.interval)
        except AttributeError:
            # sys.setswitchinterval is only python3
            pass

        self.taskQueue = asynctaskqueue.AsyncTaskQueue()
        self.pendingTasks = []
        self.threads = []
        self.timer = TimerCallback(callback=self._onTimer, targetFps=1/self.interval)

        # call timer.start here to initialize the QTimer now on the main thread
        self.timer.start() 

def test_enumerate_after_join(self):
        # Try hard to trigger #1703448: a thread is still returned in
        # threading.enumerate() after it has been join()ed.
        enum = threading.enumerate
        old_interval = sys.getcheckinterval()
        sys.setcheckinterval(1)
        try:
            for i in xrange(1, 1000):
                t = threading.Thread(target=lambda: None)
                t.start()
                t.join()
                l = enum()
                self.assertFalse(t in l,
                    "#1703448 triggered after %d trials: %s" % (i, l))
        finally:
            sys.setcheckinterval(old_interval) 

def setUp(self):
        """
        Reduce the CPython check interval so that thread switches happen much
        more often, hopefully exercising more possible race conditions.  Also,
        delay actual test startup until the reactor has been started.
        """
        if hasattr(sys, 'getcheckinterval'):
            self.addCleanup(sys.setcheckinterval, sys.getcheckinterval())
            sys.setcheckinterval(7)
        # XXX This is a trial hack.  We need to make sure the reactor
        # actually *starts* for isInIOThread() to have a meaningful result.
        # Returning a Deferred here should force that to happen, if it has
        # not happened already.  In the future, this should not be
        # necessary.
        d = defer.Deferred()
        reactor.callLater(0, d.callback, None)
        return d 

def test_is_alive_after_fork(self):
        # Try hard to trigger #18418: is_alive() could sometimes be True on
        # threads that vanished after a fork.
        old_interval = sys.getcheckinterval()

        # Make the bug more likely to manifest.
        sys.setcheckinterval(10)

        try:
            for i in range(20):
                t = threading.Thread(target=lambda: None)
                t.start()
                pid = os.fork()
                if pid == 0:
                    os._exit(1 if t.is_alive() else 0)
                else:
                    t.join()
                    pid, status = os.waitpid(pid, 0)
                    self.assertEqual(0, status)
        finally:
            sys.setcheckinterval(old_interval) 

def test_enumerate_after_join(self):
        # Try hard to trigger #1703448: a thread is still returned in
        # threading.enumerate() after it has been join()ed.
        enum = threading.enumerate
        old_interval = sys.getcheckinterval()
        try:
            for i in xrange(1, 100):
                # Try a couple times at each thread-switching interval
                # to get more interleavings.
                sys.setcheckinterval(i // 5)
                t = threading.Thread(target=lambda: None)
                t.start()
                t.join()
                l = enum()
                self.assertNotIn(t, l,
                    "#1703448 triggered after %d trials: %s" % (i, l))
        finally:
            sys.setcheckinterval(old_interval) 

def adjust_balance_concurrently(self, account):
        def transact():
            account.deposit(5)
            time.sleep(0.001)
            account.withdraw(5)

        # Greatly improve the chance of an operation being interrupted
        # by thread switch, thus testing synchronization effectively
        try:
            sys.setswitchinterval(1e-12)
        except AttributeError:
            # For Python 2 compatibility
            sys.setcheckinterval(1)

        threads = [threading.Thread(target=transact) for _ in range(1000)]
        for thread in threads:
            thread.start()
        for thread in threads:
            thread.join()

    # Utility functions 

def collect_in_thread(period=0.001):
    """
    Ensure GC collections happen in a different thread, at a high frequency.
    """
    threading = test_support.import_module('threading')
    please_stop = False

    def collect():
        while not please_stop:
            time.sleep(period)
            gc.collect()

    with test_support.disable_gc():
        old_interval = sys.getcheckinterval()
        sys.setcheckinterval(20)
        t = threading.Thread(target=collect)
        t.start()
        try:
            yield
        finally:
            please_stop = True
            t.join()
            sys.setcheckinterval(old_interval) 

def test_is_alive_after_fork(self):
        # Try hard to trigger #18418: is_alive() could sometimes be True on
        # threads that vanished after a fork.
        old_interval = sys.getcheckinterval()

        # Make the bug more likely to manifest.
        sys.setcheckinterval(10)

        try:
            for i in range(20):
                t = threading.Thread(target=lambda: None)
                t.start()
                pid = os.fork()
                if pid == 0:
                    os._exit(1 if t.is_alive() else 0)
                else:
                    t.join()
                    pid, status = os.waitpid(pid, 0)
                    self.assertEqual(0, status)
        finally:
            sys.setcheckinterval(old_interval) 

def test_enumerate_after_join(self):
        # Try hard to trigger #1703448: a thread is still returned in
        # threading.enumerate() after it has been join()ed.
        enum = threading.enumerate
        old_interval = sys.getcheckinterval()
        try:
            for i in xrange(1, 100):
                # Try a couple times at each thread-switching interval
                # to get more interleavings.
                sys.setcheckinterval(i // 5)
                t = threading.Thread(target=lambda: None)
                t.start()
                t.join()
                l = enum()
                self.assertNotIn(t, l,
                    "#1703448 triggered after %d trials: %s" % (i, l))
        finally:
            sys.setcheckinterval(old_interval) 

def test_enumerate_after_join(self):
        # Try hard to trigger #1703448: a thread is still returned in
        # threading.enumerate() after it has been join()ed.
        enum = threading.enumerate
        old_interval = sys.getcheckinterval()
        try:
            for i in xrange(1, 100):
                # Try a couple times at each thread-switching interval
                # to get more interleavings.
                sys.setcheckinterval(i // 5)
                t = threading.Thread(target=lambda: None)
                t.start()
                t.join()
                l = enum()
                self.assertNotIn(t, l,
                    "#1703448 triggered after %d trials: %s" % (i, l))
        finally:
            sys.setcheckinterval(old_interval) 

def test_enumerate_after_join(self):
        # Try hard to trigger #1703448: a thread is still returned in
        # threading.enumerate() after it has been join()ed.
        enum = threading.enumerate
        old_interval = sys.getcheckinterval()
        try:
            for i in xrange(1, 100):
                # Try a couple times at each thread-switching interval
                # to get more interleavings.
                sys.setcheckinterval(i // 5)
                t = threading.Thread(target=lambda: None)
                t.start()
                t.join()
                l = enum()
                self.assertNotIn(t, l,
                    "#1703448 triggered after %d trials: %s" % (i, l))
        finally:
            sys.setcheckinterval(old_interval) 

def request_priority_execution():
    gc.disable()
    sys.setcheckinterval(999999999)
    if sys.version_info > (3, 0, 0):
        sys.setswitchinterval(1000)
    p = psutil.Process(os.getpid())
    try:
        if platform.system() == "Windows":
            p.nice(psutil.HIGH_PRIORITY_CLASS)
        else:
            p.nice(10)
    except psutil.AccessDenied:
        pass

    return p 

def test_setcheckinterval(self):
        self.assertRaises(TypeError, sys.setcheckinterval)
        orig = sys.getcheckinterval()
        for n in 0, 100, 120, orig: # orig last to restore starting state
            sys.setcheckinterval(n)
            self.assertEquals(sys.getcheckinterval(), n) 

def test_setcheckinterval(self):
        self.assertRaises(TypeError, sys.setcheckinterval)
        orig = sys.getcheckinterval()
        for n in 0, 100, 120, orig: # orig last to restore starting state
            sys.setcheckinterval(n)
            self.assertEqual(sys.getcheckinterval(), n) 

def release_priority_execution(p):
    sys.setcheckinterval(100)
    if sys.version_info > (3, 0, 0):
        sys.setswitchinterval(0.005)
    try:
        if platform.system() == "Windows":
            p.nice(psutil.NORMAL_PRIORITY_CLASS)
        else:
            p.nice(5)
    except psutil.AccessDenied:
        pass
    gc.enable() 

def tearDownClass(self):
            sys.setcheckinterval(self.checkInterval) 

def setUpClass(self):
            self.checkInterval = sys.getcheckinterval()
            sys.setcheckinterval(7) 

def test_setcheckinterval(self):
        self.assertRaises(TypeError, sys.setcheckinterval)
        orig = sys.getcheckinterval()
        for n in 0, 100, 120, orig: # orig last to restore starting state
            sys.setcheckinterval(n)
            self.assertEquals(sys.getcheckinterval(), n) 

def test_setcheckinterval(self):
        with warnings.catch_warnings():
            warnings.simplefilter("ignore")
            self.assertRaises(TypeError, sys.setcheckinterval)
            orig = sys.getcheckinterval()
            for n in 0, 100, 120, orig: # orig last to restore starting state
                sys.setcheckinterval(n)
                self.assertEqual(sys.getcheckinterval(), n) 

def test_setcheckinterval(self):
        self.assertRaises(TypeError, sys.setcheckinterval)
        orig = sys.getcheckinterval()
        for n in 0, 100, 120, orig: # orig last to restore starting state
            sys.setcheckinterval(n)
            self.assertEqual(sys.getcheckinterval(), n) 

def test_setcheckinterval(self):
        self.assertRaises(TypeError, sys.setcheckinterval)
        orig = sys.getcheckinterval()
        for n in 0, 100, 120, orig: # orig last to restore starting state
            sys.setcheckinterval(n)
            self.assertEqual(sys.getcheckinterval(), n) 

def test_setcheckinterval(self):
        self.assertRaises(TypeError, sys.setcheckinterval)
        orig = sys.getcheckinterval()
        for n in 0, 100, 120, orig: # orig last to restore starting state
            sys.setcheckinterval(n)
            self.assertEquals(sys.getcheckinterval(), n) 

def test_setcheckinterval(self):
        with warnings.catch_warnings():
            warnings.simplefilter("ignore")
            self.assertRaises(TypeError, sys.setcheckinterval)
            orig = sys.getcheckinterval()
            for n in 0, 100, 120, orig: # orig last to restore starting state
                sys.setcheckinterval(n)
                self.assertEqual(sys.getcheckinterval(), n) 

def setUp(self):
        """
        Reduce the CPython check interval so that thread switches happen much
        more often, hopefully exercising more possible race conditions.  Also,
        delay actual test startup until the reactor has been started.
        """
        if _PY3:
            if getattr(sys, 'getswitchinterval', None) is not None:
                self.addCleanup(sys.setswitchinterval, sys.getswitchinterval())
                sys.setswitchinterval(0.0000001)
        else:
            if getattr(sys, 'getcheckinterval', None) is not None:
                self.addCleanup(sys.setcheckinterval, sys.getcheckinterval())
                sys.setcheckinterval(7) 

def test_setcheckinterval(self):
        with warnings.catch_warnings():
            warnings.simplefilter("ignore")
            self.assertRaises(TypeError, sys.setcheckinterval)
            orig = sys.getcheckinterval()
            for n in 0, 100, 120, orig: # orig last to restore starting state
                sys.setcheckinterval(n)
                self.assertEqual(sys.getcheckinterval(), n) 

def test_string_slicing_into_vector(self):
        def testFunction(ct, passCt,chars):
            x = "asdfasdf" * (ct / 8)
            res = 0
            for _ in xrange(passCt):
                v = [x[ix*chars:ix*chars+chars] for ix in xrange(len(x) / chars)]
                for e in v:
                    res = res + len(e)
            return res
        f = testFunction

        self.evaluateWithExecutor(f, 1000000, 1, 2)
        self.evaluateWithExecutor(f, 10000, 1, 2)

        def runTest(func, name):
            PerformanceTestReporter.PerfTest(name)(func)()

        runTest(lambda: self.evaluateWithExecutor(f, 1000000, 10, 2), "pyfora.string_slicing_into_vector_10mm.2_char_large_string.pyfora")
        runTest(lambda: self.evaluateWithExecutor(f, 1000000, 1000, 200), "pyfora.string_slicing_into_vector_10mm.200_char_large_string.pyfora")
        runTest(lambda: self.evaluateWithExecutor(f, 10000, 1000, 2), "pyfora.string_slicing_into_vector_10mm.2_char_small_string.pyfora")
        runTest(lambda: self.evaluateWithExecutor(f, 10000, 100000, 200), "pyfora.string_slicing_into_vector_10mm.200_char_small_string.pyfora")

        sys.setcheckinterval(100000)

        runTest(lambda: f(1000000, 10, 2), "pyfora.string_slicing_into_vector_10mm.2_char_large_string.native")
        runTest(lambda: f(1000000, 1000, 200), "pyfora.string_slicing_into_vector_10mm.200_char_large_string.native")
        runTest(lambda: f(10000, 1000, 2), "pyfora.string_slicing_into_vector_10mm.2_char_small_string.native")
        runTest(lambda: f(10000, 100000, 200), "pyfora.string_slicing_into_vector_10mm.200_char_small_string.native")

        sys.setcheckinterval(100)