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changeset: 88694:90354a4c9dde user: Victor Stinner victor.stinner@gmail.com date: Sat Jan 25 14:43:45 2014 +0100 files: Lib/selectors.py Lib/test/test_selectors.py Misc/NEWS description: Issue #20311: Revert e042ea77a152 and 7ce7295393c2, PollSelector.select() and EpollSelector.select() round again the timeout towards zero diff -r caab3e191485 -r 90354a4c9dde Lib/selectors.py --- a/Lib/selectors.py Sat Jan 25 14:40:04 2014 +0100 +++ b/Lib/selectors.py Sat Jan 25 14:43:45 2014 +0100 @@ -8,7 +8,6 @@ from abc import ABCMeta, abstractmethod from collections import namedtuple, Mapping import functools -import math import select import sys @@ -357,9 +356,8 @@ elif timeout <= 0: timeout = 0 else: - # poll() has a resolution of 1 millisecond, round away from - # zero to wait *at least* timeout seconds. - timeout = int(math.ceil(timeout * 1e3)) + # Round towards zero + timeout = int(timeout * 1000) ready = [] try: fd_event_list = self._poll.poll(timeout) @@ -415,10 +413,6 @@ timeout = -1 elif timeout <= 0: timeout = 0 - else: - # epoll_wait() has a resolution of 1 millisecond, round away - # from zero to wait *at least* timeout seconds. - timeout = math.ceil(timeout * 1e3) * 1e-3 max_ev = len(self._fd_to_key) ready = [] try: diff -r caab3e191485 -r 90354a4c9dde Lib/test/test_selectors.py --- a/Lib/test/test_selectors.py Sat Jan 25 14:40:04 2014 +0100 +++ b/Lib/test/test_selectors.py Sat Jan 25 14:43:45 2014 +0100 @@ -363,25 +363,6 @@ self.assertFalse(s.select(2)) self.assertLess(time() - t, 2.5) - def test_timeout_rounding(self): - # Issue #20311: Timeout must be rounded away from zero to wait *at - # least* timeout seconds. For example, epoll_wait() has a resolution of - # 1 ms (10^-3), epoll.select(0.0001) must wait 1 ms, not 0 ms. - s = self.SELECTOR() - self.addCleanup(s.close) - - rd, wr = self.make_socketpair() - s.register(rd, selectors.EVENT_READ) - - for timeout in (1e-2, 1e-3, 1e-4): - t0 = perf_counter() - s.select(timeout) - dt = perf_counter() - t0 - clock = get_clock_info('perf_counter') - self.assertGreaterEqual(dt, timeout, - "%.30f < %.30f ; clock=%s" - % (dt, timeout, clock)) - class ScalableSelectorMixIn: diff -r caab3e191485 -r 90354a4c9dde Misc/NEWS --- a/Misc/NEWS Sat Jan 25 14:40:04 2014 +0100 +++ b/Misc/NEWS Sat Jan 25 14:43:45 2014 +0100 @@ -40,11 +40,6 @@ which it could get an inspect.Signature is a callable written in Python. Fix courtesy of Michael Foord. -- Issue #20311: selector.PollSelector.select() 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 #20317: ExitStack.__exit__ could create a self-referential loop if an exception raised by a cleanup operation already had its context set correctly (for example, by the @contextmanager decorator). The infinite /victor.stinner@gmail.com