[Python-checkins] cpython: Issue #23646: Enhance precision of time.sleep() and socket timeout when

[victor.stinner]

https://hg.python.org/cpython/rev/9882cc2efd36
changeset:   95081:9882cc2efd36
user:        Victor Stinner <victor.stinner at gmail.com>
date:        Fri Mar 20 01:42:20 2015 +0100
summary:
  Issue #23646: Enhance precision of time.sleep() and socket timeout when
interrupted by a signal

Add a new _PyTime_AddDouble() function and remove _PyTime_ADD_SECONDS() macro.
The _PyTime_ADD_SECONDS only supported an integer number of seconds, the
_PyTime_AddDouble() has subsecond resolution.

files:
  Include/pytime.h                   |  12 +++++-------
  Lib/test/eintrdata/eintr_tester.py |   7 ++-----
  Modules/socketmodule.c             |   2 +-
  Modules/timemodule.c               |   4 ++--
  Python/pytime.c                    |  17 +++++++++++++++++
  5 files changed, 27 insertions(+), 15 deletions(-)


diff --git a/Include/pytime.h b/Include/pytime.h
--- a/Include/pytime.h
+++ b/Include/pytime.h
@@ -41,13 +41,6 @@
     _PyTime_timeval *tp,
     _Py_clock_info_t *info);
 
-#define _PyTime_ADD_SECONDS(tv, interval) \
-do { \
-    tv.tv_usec += (long) (((long) interval - interval) * 1000000); \
-    tv.tv_sec += (time_t) interval + (time_t) (tv.tv_usec / 1000000); \
-    tv.tv_usec %= 1000000; \
-} while (0)
-
 #define _PyTime_INTERVAL(tv_start, tv_end) \
     ((tv_end.tv_sec - tv_start.tv_sec) + \
      (tv_end.tv_usec - tv_start.tv_usec) * 0.000001)
@@ -109,6 +102,11 @@
     _PyTime_timeval *tp,
     _Py_clock_info_t *info);
 
+/* Add interval seconds to tv */
+PyAPI_FUNC(void)
+_PyTime_AddDouble(_PyTime_timeval *tv, double interval,
+                  _PyTime_round_t round);
+
 /* Initialize time.
    Return 0 on success, raise an exception and return -1 on error. */
 PyAPI_FUNC(int) _PyTime_Init(void);
diff --git a/Lib/test/eintrdata/eintr_tester.py b/Lib/test/eintrdata/eintr_tester.py
--- a/Lib/test/eintrdata/eintr_tester.py
+++ b/Lib/test/eintrdata/eintr_tester.py
@@ -258,13 +258,10 @@
 
     def test_sleep(self):
         t0 = time.monotonic()
-        # time.sleep() may retry when interrupted by a signal
-        time.sleep(2)
+        time.sleep(self.sleep_time)
         signal.alarm(0)
         dt = time.monotonic() - t0
-        # Tolerate a difference 100 ms: on Windows, time.monotonic() has
-        # a resolution of 15.6 ms or greater
-        self.assertGreaterEqual(dt, 1.9)
+        self.assertGreaterEqual(dt, self.sleep_time)
 
 
 def test_main():
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -687,7 +687,7 @@
         if (has_timeout) { \
             _PyTime_monotonic(&now); \
             deadline = now; \
-            _PyTime_ADD_SECONDS(deadline, s->sock_timeout); \
+            _PyTime_AddDouble(&deadline, s->sock_timeout, _PyTime_ROUND_UP); \
         } \
         while (1) { \
             errno = 0; \
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -1399,14 +1399,14 @@
 #endif
 
     _PyTime_monotonic(&deadline);
-    _PyTime_ADD_SECONDS(deadline, secs);
+    _PyTime_AddDouble(&deadline, secs, _PyTime_ROUND_UP);
 
     do {
 #ifndef MS_WINDOWS
         frac = fmod(secs, 1.0);
         secs = floor(secs);
         timeout.tv_sec = (long)secs;
-        timeout.tv_usec = (long)(frac*1000000.0);
+        timeout.tv_usec = (long)(frac*1e6);
 
         Py_BEGIN_ALLOW_THREADS
         err = select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout);
diff --git a/Python/pytime.c b/Python/pytime.c
--- a/Python/pytime.c
+++ b/Python/pytime.c
@@ -367,6 +367,23 @@
     return _PyTime_ObjectToDenominator(obj, sec, usec, 1e6, round);
 }
 
+void
+_PyTime_AddDouble(_PyTime_timeval *tv, double interval, _PyTime_round_t round)
+{
+    _PyTime_timeval tv2;
+    double frac;
+
+    frac = fmod(interval, 1.0);
+    interval = floor(interval);
+    tv2.tv_sec = (long)interval;
+    tv2.tv_usec = (long)(frac*1e6);
+
+    tv->tv_sec += tv2.tv_sec;
+    tv->tv_usec += tv2.tv_usec;
+    tv->tv_sec += (time_t)(tv->tv_usec / 1000000);
+    tv->tv_usec %= 1000000;
+}
+
 int
 _PyTime_Init(void)
 {

-- 
Repository URL: https://hg.python.org/cpython