Remove resolution and _granularity from selectors and asyncio

* Remove selectors.BaseSelector.resolution attribute
* Remove asyncio.BaseEventLoop._granularity attribute

6 files changed, 10 insertions, 42 deletions

diff --git a/asyncio/base_events.py b/asyncio/base_events.py
index cafd10a..db57ee8 100644
--- a/asyncio/base_events.py
+++ b/asyncio/base_events.py
@@ -96,7 +96,6 @@ class BaseEventLoop(events.AbstractEventLoop):
         self._default_executor = None
         self._internal_fds = 0
         self._running = False
-        self._granularity = time.get_clock_info('monotonic').resolution
 
     def _make_socket_transport(self, sock, protocol, waiter=None, *,
                                extra=None, server=None):
@@ -638,7 +637,7 @@ class BaseEventLoop(events.AbstractEventLoop):
         self._process_events(event_list)
 
         # Handle 'later' callbacks that are ready.
-        now = self.time() + self._granularity
+        now = self.time()
         while self._scheduled:
             handle = self._scheduled[0]
             if handle._when > now:
diff --git a/asyncio/proactor_events.py b/asyncio/proactor_events.py
index 6b5707c..74566b2 100644
--- a/asyncio/proactor_events.py
+++ b/asyncio/proactor_events.py
@@ -365,7 +365,6 @@ class BaseProactorEventLoop(base_events.BaseEventLoop):
         self._selector = proactor   # convenient alias
         self._self_reading_future = None
         self._accept_futures = {}   # socket file descriptor => Future
-        self._granularity = max(proactor.resolution, self._granularity)
         proactor.set_loop(self)
         self._make_self_pipe()
 
diff --git a/asyncio/selector_events.py b/asyncio/selector_events.py
index 3690145..202c14b 100644
--- a/asyncio/selector_events.py
+++ b/asyncio/selector_events.py
@@ -36,7 +36,6 @@ class BaseSelectorEventLoop(base_events.BaseEventLoop):
             selector = selectors.DefaultSelector()
         logger.debug('Using selector: %s', selector.__class__.__name__)
         self._selector = selector
-        self._granularity = max(selector.resolution, self._granularity)
         self._make_self_pipe()
 
     def _make_socket_transport(self, sock, protocol, waiter=None, *,
diff --git a/asyncio/selectors.py b/asyncio/selectors.py
index 056e45c..bb2a45a 100644
--- a/asyncio/selectors.py
+++ b/asyncio/selectors.py
@@ -83,11 +83,6 @@ class BaseSelector(metaclass=ABCMeta):
     performant implementation on the current platform.
     """
 
-    @abstractproperty
-    def resolution(self):
-        """Resolution of the selector in seconds"""
-        return None
-
     @abstractmethod
     def register(self, fileobj, events, data=None):
         """Register a file object.
@@ -289,10 +284,6 @@ class SelectSelector(_BaseSelectorImpl):
         self._readers = set()
         self._writers = set()
 
-    @property
-    def resolution(self):
-        return 1e-6
-
     def register(self, fileobj, events, data=None):
         key = super().register(fileobj, events, data)
         if events & EVENT_READ:
@@ -345,10 +336,6 @@ if hasattr(select, 'poll'):
             super().__init__()
             self._poll = select.poll()
 
-        @property
-        def resolution(self):
-            return 1e-3
-
         def register(self, fileobj, events, data=None):
             key = super().register(fileobj, events, data)
             poll_events = 0
@@ -400,10 +387,6 @@ if hasattr(select, 'epoll'):
             super().__init__()
             self._epoll = select.epoll()
 
-        @property
-        def resolution(self):
-            return 1e-3
-
         def fileno(self):
             return self._epoll.fileno()
 
@@ -468,10 +451,6 @@ if hasattr(select, 'kqueue'):
             super().__init__()
             self._kqueue = select.kqueue()
 
-        @property
-        def resolution(self):
-            return 1e-9
-
         def fileno(self):
             return self._kqueue.fileno()
 
diff --git a/tests/test_base_events.py b/tests/test_base_events.py
index 0d90d3f..5b05684 100644
--- a/tests/test_base_events.py
+++ b/tests/test_base_events.py
@@ -124,7 +124,8 @@ class BaseEventLoopTests(unittest.TestCase):
         self.loop.run_forever()
         dt = self.loop.time() - t0
 
-        self.assertGreaterEqual(dt, delay - self.loop._granularity, dt)
+        # 50 ms: maximum granularity of the event loop
+        self.assertGreaterEqual(dt, delay - 0.050, dt)
         # tolerate a difference of +800 ms because some Python buildbots
         # are really slow
         self.assertLessEqual(dt, 0.9, dt)
diff --git a/tests/test_events.py b/tests/test_events.py
index c11d20f..c2988c0 100644
--- a/tests/test_events.py
+++ b/tests/test_events.py
@@ -1170,28 +1170,19 @@ class EventLoopTestsMixin:
         orig_run_once = self.loop._run_once
         self.loop._run_once_counter = 0
         self.loop._run_once = _run_once
-        calls = []
 
         @asyncio.coroutine
         def wait():
             loop = self.loop
-            calls.append(loop._run_once_counter)
-            yield from asyncio.sleep(loop._granularity * 10, loop=loop)
-            calls.append(loop._run_once_counter)
-            yield from asyncio.sleep(loop._granularity / 10, loop=loop)
-            calls.append(loop._run_once_counter)
+            yield from asyncio.sleep(1e-2, loop=loop)
+            yield from asyncio.sleep(1e-4, loop=loop)
 
         self.loop.run_until_complete(wait())
-        calls.append(self.loop._run_once_counter)
-        self.assertEqual(calls, [1, 3, 5, 6])
-
-    def test_granularity(self):
-        granularity = self.loop._granularity
-        self.assertGreater(granularity, 0.0)
-        # Worst expected granularity: 1 ms on Linux (limited by poll/epoll
-        # resolution), 15.6 ms on Windows (limited by time.monotonic
-        # resolution)
-        self.assertLess(granularity, 0.050)
+        # The ideal number of call is 6, but on some platforms, the selector
+        # may sleep at little bit less than timeout depending on the resolution
+        # of the clock used by the kernel. Tolerate 2 useless calls on these
+        # platforms.
+        self.assertLessEqual(self.loop._run_once_counter, 8)
 
 
 class SubprocessTestsMixin: