我们从Python开源项目中，提取了以下26个代码示例，用于说明如何使用sys.setswitchinterval()。
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 newgil = hasattr(sys, 'getswitchinterval') if newgil: geti, seti = sys.getswitchinterval, sys.setswitchinterval else: geti, seti = sys.getcheckinterval, sys.setcheckinterval old_interval = geti() try: for i in range(1, 100): seti(i * 0.0002 if newgil else 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: seti(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.getswitchinterval() self.addCleanup(sys.setswitchinterval, old_interval) # Make the bug more likely to manifest. sys.setswitchinterval(1e-6) for i in range(20): t = threading.Thread(target=lambda: None) t.start() self.addCleanup(t.join) pid = os.fork() if pid == 0: os._exit(1 if t.is_alive() else 0) else: pid, status = os.waitpid(pid, 0) self.assertEqual(0, status)
def test_switchinterval(self): self.assertRaises(TypeError, sys.setswitchinterval) self.assertRaises(TypeError, sys.setswitchinterval, "a") self.assertRaises(ValueError, sys.setswitchinterval, -1.0) self.assertRaises(ValueError, sys.setswitchinterval, 0.0) orig = sys.getswitchinterval() # sanity check self.assertTrue(orig < 0.5, orig) try: for n in 0.00001, 0.05, 3.0, orig: sys.setswitchinterval(n) self.assertAlmostEqual(sys.getswitchinterval(), n) finally: sys.setswitchinterval(orig)
def test_main(): old_switchinterval = None try: old_switchinterval = sys.getswitchinterval() sys.setswitchinterval(1e-5) except AttributeError: pass try: run_unittest(ThreadedImportTests) finally: if old_switchinterval is not None: sys.setswitchinterval(old_switchinterval)
def setUp(self): try: self.old_switchinterval = sys.getswitchinterval() sys.setswitchinterval(0.000001) except AttributeError: self.old_switchinterval = None
def tearDown(self): if self.old_switchinterval is not None: sys.setswitchinterval(self.old_switchinterval)
def test_pending_calls_race(self): # Issue #14406: multi-threaded race condition when waiting on all # futures. event = threading.Event() def future_func(): event.wait() oldswitchinterval = sys.getswitchinterval() sys.setswitchinterval(1e-6) try: fs = {self.executor.submit(future_func) for i in range(100)} event.set() futures.wait(fs, return_when=futures.ALL_COMPLETED) finally: sys.setswitchinterval(oldswitchinterval)
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_thread_safety_during_modification(self): hosts = range(100) policy = RoundRobinPolicy() policy.populate(None, hosts) errors = [] def check_query_plan(): try: for i in xrange(100): list(policy.make_query_plan()) except Exception as exc: errors.append(exc) def host_up(): for i in xrange(1000): policy.on_up(randint(0, 99)) def host_down(): for i in xrange(1000): policy.on_down(randint(0, 99)) threads = [] for i in range(5): threads.append(Thread(target=check_query_plan)) threads.append(Thread(target=host_up)) threads.append(Thread(target=host_down)) # make the GIL switch after every instruction, maximizing # the chance of race conditions check = six.PY2 or '__pypy__' in sys.builtin_module_names if check: original_interval = sys.getcheckinterval() else: original_interval = sys.getswitchinterval() try: if check: sys.setcheckinterval(0) else: sys.setswitchinterval(0.0001) map(lambda t: t.start(), threads) map(lambda t: t.join(), threads) finally: if check: sys.setcheckinterval(original_interval) else: sys.setswitchinterval(original_interval) if errors: self.fail("Saw errors: %s" % (errors,))
def test_trashcan_threads(self): # Issue #13992: trashcan mechanism should be thread-safe NESTING = 60 N_THREADS = 2 def sleeper_gen(): """A generator that releases the GIL when closed or dealloc'ed.""" try: yield finally: time.sleep(0.000001) class C(list): # Appending to a list is atomic, which avoids the use of a lock. inits = [] dels = [] def __init__(self, alist): self[:] = alist C.inits.append(None) def __del__(self): # This __del__ is called by subtype_dealloc(). C.dels.append(None) # `g` will release the GIL when garbage-collected. This # helps assert subtype_dealloc's behaviour when threads # switch in the middle of it. g = sleeper_gen() next(g) # Now that __del__ is finished, subtype_dealloc will proceed # to call list_dealloc, which also uses the trashcan mechanism. def make_nested(): """Create a sufficiently nested container object so that the trashcan mechanism is invoked when deallocating it.""" x = C([]) for i in range(NESTING): x = [C([x])] del x def run_thread(): """Exercise make_nested() in a loop.""" while not exit: make_nested() old_switchinterval = sys.getswitchinterval() sys.setswitchinterval(1e-5) try: exit = False threads = [] for i in range(N_THREADS): t = threading.Thread(target=run_thread) threads.append(t) for t in threads: t.start() time.sleep(1.0) exit = True for t in threads: t.join() finally: sys.setswitchinterval(old_switchinterval) gc.collect() self.assertEqual(len(C.inits), len(C.dels))
def test_trashcan_threads(self): # Issue #13992: trashcan mechanism should be thread-safe NESTING = 60 N_THREADS = 2 def sleeper_gen(): """A generator that releases the GIL when closed or dealloc'ed.""" try: yield finally: time.sleep(0.000001) class C(list): # Appending to a list is atomic, which avoids the use of a lock. inits = [] dels = [] def __init__(self, alist): self[:] = alist C.inits.append(None) def __del__(self): # This __del__ is called by subtype_dealloc(). C.dels.append(None) # `g` will release the GIL when garbage-collected. This # helps assert subtype_dealloc's behaviour when threads # switch in the middle of it. g = sleeper_gen() next(g) # Now that __del__ is finished, subtype_dealloc will proceed # to call list_dealloc, which also uses the trashcan mechanism. def make_nested(): """Create a sufficiently nested container object so that the trashcan mechanism is invoked when deallocating it.""" x = C([]) for i in range(NESTING): x = [C([x])] del x def run_thread(): """Exercise make_nested() in a loop.""" while not exit: make_nested() old_switchinterval = sys.getswitchinterval() sys.setswitchinterval(1e-5) try: exit = [] threads = [] for i in range(N_THREADS): t = threading.Thread(target=run_thread) threads.append(t) with start_threads(threads, lambda: exit.append(1)): time.sleep(1.0) finally: sys.setswitchinterval(old_switchinterval) gc.collect() self.assertEqual(len(C.inits), len(C.dels))
def test_thread_safety_during_modification(self): hosts = range(100) policy = RoundRobinPolicy() policy.populate(None, hosts) errors = [] def check_query_plan(): try: for i in xrange(100): list(policy.make_query_plan()) except Exception as exc: errors.append(exc) def host_up(): for i in xrange(1000): policy.on_up(randint(0, 99)) def host_down(): for i in xrange(1000): policy.on_down(randint(0, 99)) threads = [] for i in range(5): threads.append(Thread(target=check_query_plan)) threads.append(Thread(target=host_up)) threads.append(Thread(target=host_down)) # make the GIL switch after every instruction, maximizing # the chance of race conditions check = six.PY2 or '__pypy__' in sys.builtin_module_names if check: original_interval = sys.getcheckinterval() else: original_interval = sys.getswitchinterval() try: if check: sys.setcheckinterval(0) else: sys.setswitchinterval(0.0001) for t in threads: t.start() for t in threads: t.join() finally: if check: sys.setcheckinterval(original_interval) else: sys.setswitchinterval(original_interval) if errors: self.fail("Saw errors: %s" % (errors,))
