Issue #22043: time.monotonic() is now always available

vstinner · vstinner · commit ae58649721ec · 2014-09-02T23:18:25.000+02:00
threading.Lock.acquire(), threading.RLock.acquire() and socket operations now
use a monotonic clock, instead of the system clock, when a timeout is used.
diff --git a/Doc/library/time.rst b/Doc/library/time.rst
@@ -315,9 +315,9 @@ The module defines the following functions and data items:
    processes running for more than 49 days. On more recent versions of Windows
    and on other operating systems, :func:`monotonic` is system-wide.
 
-   Availability: Windows, Mac OS X, Linux, FreeBSD, OpenBSD, Solaris.
-
    .. versionadded:: 3.3
+   .. versionchanged:: 3.5
+      The function is now always available.
 
 
 .. function:: perf_counter()
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
@@ -238,6 +238,11 @@ socket
   :meth:`socket.socket.send`.
   (contributed by Giampaolo Rodola' in :issue:`17552`)
 
+time
+----
+
+The :func:`time.monotonic` function is now always available (:issue`22043`).
+
 wsgiref
 -------
 
diff --git a/Include/pytime.h b/Include/pytime.h
@@ -91,6 +91,24 @@ PyAPI_FUNC(int) _PyTime_ObjectToTimespec(
     long *nsec,
     _PyTime_round_t);
 
+/* Get the time of a monotonic clock, i.e. a clock that cannot go backwards.
+   The clock is not affected by system clock updates. The reference point of
+   the returned value is undefined, so that only the difference between the
+   results of consecutive calls is valid.
+
+   The function never fails. _PyTime_Init() ensures that a monotonic clock
+   is available and works. */
+PyAPI_FUNC(void) _PyTime_monotonic(
+    _PyTime_timeval *tp);
+
+/* Similar to _PyTime_monotonic(), fill also info (if set) with information of
+   the function used to get the time.
+
+   Return 0 on success, raise an exception and return -1 on error. */
+PyAPI_FUNC(int) _PyTime_monotonic_info(
+    _PyTime_timeval *tp,
+    _Py_clock_info_t *info);
+
 /* Initialize time.
    Return 0 on success, raise an exception and return -1 on error. */
 PyAPI_FUNC(int) _PyTime_Init(void);
diff --git a/Lib/queue.py b/Lib/queue.py
@@ -6,10 +6,7 @@
     import dummy_threading as threading
 from collections import deque
 from heapq import heappush, heappop
-try:
-    from time import monotonic as time
-except ImportError:
-    from time import time
+from time import monotonic as time
 
 __all__ = ['Empty', 'Full', 'Queue', 'PriorityQueue', 'LifoQueue']
 
diff --git a/Lib/sched.py b/Lib/sched.py
@@ -35,10 +35,7 @@
     import threading
 except ImportError:
     import dummy_threading as threading
-try:
-    from time import monotonic as _time
-except ImportError:
-    from time import time as _time
+from time import monotonic as _time
 
 __all__ = ["scheduler"]
 
diff --git a/Lib/socketserver.py b/Lib/socketserver.py
@@ -136,10 +136,7 @@ class will essentially render the service "deaf" while one request is
     import threading
 except ImportError:
     import dummy_threading as threading
-try:
-    from time import monotonic as time
-except ImportError:
-    from time import time as time
+from time import monotonic as time
 
 __all__ = ["TCPServer","UDPServer","ForkingUDPServer","ForkingTCPServer",
            "ThreadingUDPServer","ThreadingTCPServer","BaseRequestHandler",
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
@@ -365,10 +365,7 @@ class Popen(args, bufsize=-1, executable=None,
 import builtins
 import warnings
 import errno
-try:
-    from time import monotonic as _time
-except ImportError:
-    from time import time as _time
+from time import monotonic as _time
 
 # Exception classes used by this module.
 class SubprocessError(Exception): pass
diff --git a/Lib/telnetlib.py b/Lib/telnetlib.py
@@ -36,10 +36,7 @@
 import sys
 import socket
 import selectors
-try:
-    from time import monotonic as _time
-except ImportError:
-    from time import time as _time
+from time import monotonic as _time
 
 __all__ = ["Telnet"]
 
diff --git a/Lib/test/test_selectors.py b/Lib/test/test_selectors.py
@@ -8,10 +8,7 @@
 from time import sleep
 import unittest
 import unittest.mock
-try:
-    from time import monotonic as time
-except ImportError:
-    from time import time as time
+from time import monotonic as time
 try:
     import resource
 except ImportError:
diff --git a/Lib/threading.py b/Lib/threading.py
@@ -3,10 +3,7 @@
 import sys as _sys
 import _thread
 
-try:
-    from time import monotonic as _time
-except ImportError:
-    from time import time as _time
+from time import monotonic as _time
 from traceback import format_exc as _format_exc
 from _weakrefset import WeakSet
 from itertools import islice as _islice
diff --git a/Lib/trace.py b/Lib/trace.py
@@ -59,10 +59,7 @@
 import dis
 import pickle
 from warnings import warn as _warn
-try:
-    from time import monotonic as _time
-except ImportError:
-    from time import time as _time
+from time import monotonic as _time
 
 try:
     import threading
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -129,6 +129,11 @@ Core and Builtins
 Library
 -------
 
+- Issue #22043: time.monotonic() is now always available.
+  ``threading.Lock.acquire()``, ``threading.RLock.acquire()`` and socket
+  operations now use a monotonic clock, instead of the system clock, when a
+  timeout is used.
+
 - Issue #21527: Add a default number of workers to ThreadPoolExecutor equal
   to 5 times the number of CPUs.  Patch by Claudiu Popa.
 
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
@@ -57,7 +57,7 @@ acquire_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds)
 
 
     if (microseconds > 0) {
-        _PyTime_gettimeofday(&endtime);
+        _PyTime_monotonic(&endtime);
         endtime.tv_sec += microseconds / (1000 * 1000);
         endtime.tv_usec += microseconds % (1000 * 1000);
     }
@@ -83,7 +83,7 @@ acquire_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds)
             /* If we're using a timeout, recompute the timeout after processing
              * signals, since those can take time.  */
             if (microseconds > 0) {
-                _PyTime_gettimeofday(&curtime);
+                _PyTime_monotonic(&curtime);
                 microseconds = ((endtime.tv_sec - curtime.tv_sec) * 1000000 +
                                 (endtime.tv_usec - curtime.tv_usec));
 
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
@@ -25,7 +25,7 @@
 
 #include "Python.h"
 #include "frameobject.h"        /* for PyFrame_ClearFreeList */
-#include "pytime.h"           /* for _PyTime_gettimeofday, _PyTime_INTERVAL */
+#include "pytime.h"             /* for _PyTime_monotonic, _PyTime_INTERVAL */
 
 /* Get an object's GC head */
 #define AS_GC(o) ((PyGC_Head *)(o)-1)
@@ -919,7 +919,7 @@ collect(int generation, Py_ssize_t *n_collected, Py_ssize_t *n_uncollectable,
         for (i = 0; i < NUM_GENERATIONS; i++)
             PySys_FormatStderr(" %zd",
                               gc_list_size(GEN_HEAD(i)));
-        _PyTime_gettimeofday(&t1);
+        _PyTime_monotonic(&t1);
 
         PySys_WriteStderr("\n");
     }
@@ -1025,7 +1025,7 @@ collect(int generation, Py_ssize_t *n_collected, Py_ssize_t *n_uncollectable,
     }
     if (debug & DEBUG_STATS) {
         _PyTime_timeval t2;
-        _PyTime_gettimeofday(&t2);
+        _PyTime_monotonic(&t2);
 
         if (m == 0 && n == 0)
             PySys_WriteStderr("gc: done");
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
@@ -680,7 +680,7 @@ internal_select(PySocketSockObject *s, int writing)
         double interval = s->sock_timeout; \
         int has_timeout = s->sock_timeout > 0.0; \
         if (has_timeout) { \
-            _PyTime_gettimeofday(&now); \
+            _PyTime_monotonic(&now); \
             deadline = now; \
             _PyTime_ADD_SECONDS(deadline, s->sock_timeout); \
         } \
@@ -691,7 +691,7 @@ internal_select(PySocketSockObject *s, int writing)
             if (!has_timeout || \
                 (!CHECK_ERRNO(EWOULDBLOCK) && !CHECK_ERRNO(EAGAIN))) \
                 break; \
-            _PyTime_gettimeofday(&now); \
+            _PyTime_monotonic(&now); \
             interval = _PyTime_INTERVAL(now, deadline); \
         } \
     } \
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
diff --git a/Python/pytime.c b/Python/pytime.c
