(Merge 3.3) Issue #20311: Revert 033137c12d88 (02f9db3e684e),

select.epoll.poll() rounds again the timeout towards zero

Lib/test/test_epoll.py

@@ -254,17 +254,6 @@ class TestEPoll(unittest.TestCase):
         self.addCleanup(epoll.close)
         self.assertEqual(os.get_inheritable(epoll.fileno()), False)
 
-    def test_timeout_rounding(self):
-        # epoll_wait() has a resolution of 1 millisecond, check if the timeout
-        # is correctly rounded to the upper bound
-        epoll = select.epoll()
-        self.addCleanup(epoll.close)
-        for timeout in (1e-2, 1e-3, 1e-4):
-            t0 = time.monotonic()
-            epoll.poll(timeout)
-            dt = time.monotonic() - t0
-            self.assertGreaterEqual(dt, timeout)
-
 
 def test_main():
     support.run_unittest(TestEPoll)

Misc/NEWS

@@ -53,10 +53,6 @@ Library
 
 - Issue #20374: Fix build with GNU readline >= 6.3.
 
-- Issue #20311: select.epoll.poll() now rounds the timeout away from zero,
-  instead of rounding towards zero. For example, a timeout of one microsecond
-  is now rounded to one millisecond, instead of being rounded to zero.
-
 - Issue #20262: Warnings are raised now when duplicate names are added in the
   ZIP file or too long ZIP file comment is truncated.
 

Modules/selectmodule.c

@@ -1458,9 +1458,7 @@ pyepoll_poll(pyEpoll_Object *self, PyObject *args, PyObject *kwds)
         return NULL;
     }
     else {
-        /* epoll_wait() has a resolution of 1 millisecond, round away from zero
-           to wait *at least* dtimeout seconds. */
-        timeout = (int)ceil(dtimeout * 1000.0);
+        timeout = (int)(dtimeout * 1000.0);
     }
 
     if (maxevents == -1) {