[Python-checkins] cpython (2.7): Issue #13478: document timeit.default_timer()
sandro.tosi
python-checkins at python.org
Tue Apr 24 18:13:59 CEST 2012
http://hg.python.org/cpython/rev/86b927859155
changeset: 76524:86b927859155
branch: 2.7
parent: 76521:4dda3000c932
user: Sandro Tosi <sandro.tosi at gmail.com>
date: Tue Apr 24 18:11:29 2012 +0200
summary:
Issue #13478: document timeit.default_timer()
files:
Doc/library/timeit.rst | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/Doc/library/timeit.rst b/Doc/library/timeit.rst
--- a/Doc/library/timeit.rst
+++ b/Doc/library/timeit.rst
@@ -101,9 +101,19 @@
timeit.Timer('for i in xrange(10): oct(i)', 'gc.enable()').timeit()
-Starting with version 2.6, the module also defines two convenience functions:
+The module also defines three convenience functions:
+.. function:: default_timer()
+
+ Define a default timer, in a platform specific manner. On Windows,
+ :func:`time.clock` has microsecond granularity but :func:`time.time`'s
+ granularity is 1/60th of a second; on Unix, :func:`time.clock` has 1/100th of
+ a second granularity and :func:`time.time` is much more precise. On either
+ platform, :func:`default_timer` measures wall clock time, not the CPU
+ time. This means that other processes running on the same computer may
+ interfere with the timing.
+
.. function:: repeat(stmt[, setup[, timer[, repeat=3 [, number=1000000]]]])
Create a :class:`Timer` instance with the given statement, setup code and timer
@@ -168,13 +178,9 @@
If :option:`-n` is not given, a suitable number of loops is calculated by trying
successive powers of 10 until the total time is at least 0.2 seconds.
-The default timer function is platform dependent. On Windows,
-:func:`time.clock` has microsecond granularity but :func:`time.time`'s
-granularity is 1/60th of a second; on Unix, :func:`time.clock` has 1/100th of a
-second granularity and :func:`time.time` is much more precise. On either
-platform, the default timer functions measure wall clock time, not the CPU time.
-This means that other processes running on the same computer may interfere with
-the timing. The best thing to do when accurate timing is necessary is to repeat
+:func:`default_timer` measurations can be affected by other programs running on
+the same machine, so
+the best thing to do when accurate timing is necessary is to repeat
the timing a few times and use the best time. The :option:`-r` option is good
for this; the default of 3 repetitions is probably enough in most cases. On
Unix, you can use :func:`time.clock` to measure CPU time.
--
Repository URL: http://hg.python.org/cpython
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