From: Alex Willmer Date: Sat, 6 Mar 2021 01:22:13 +0000 (+0000) Subject: bpo-43407: Clarify comparisons of time.monotonic() et al results (GH-24757) X-Git-Tag: v3.10.0a7~190 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ff5f05934db241dfafc604989b2de3487b09ca82;p=thirdparty%2FPython%2Fcpython.git bpo-43407: Clarify comparisons of time.monotonic() et al results (GH-24757) Previous wording implied that only the result of call N and N+1 could be meaningfully compared, whereas comparing call N and N+M is fine. --- diff --git a/Doc/library/time.rst b/Doc/library/time.rst index 143f84b565f5..cfd67e87501c 100644 --- a/Doc/library/time.rst +++ b/Doc/library/time.rst @@ -277,7 +277,7 @@ Functions Return the value (in fractional seconds) 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. + difference between the results of two calls is valid. Use :func:`monotonic_ns` to avoid the precision loss caused by the :class:`float` type. @@ -306,7 +306,7 @@ Functions clock with the highest available resolution to measure a short duration. It does include time elapsed during sleep and is system-wide. The reference point of the returned value is undefined, so that only the difference between - the results of consecutive calls is valid. + the results of two calls is valid. Use :func:`perf_counter_ns` to avoid the precision loss caused by the :class:`float` type. @@ -334,7 +334,7 @@ Functions CPU time of the current process. It does not include time elapsed during sleep. It is process-wide by definition. The reference point of the returned value is undefined, so that only the difference between the results - of consecutive calls is valid. + of two calls is valid. Use :func:`process_time_ns` to avoid the precision loss caused by the :class:`float` type. @@ -626,7 +626,7 @@ Functions CPU time of the current thread. It does not include time elapsed during sleep. It is thread-specific by definition. The reference point of the returned value is undefined, so that only the difference between the results - of consecutive calls in the same thread is valid. + of two calls in the same thread is valid. Use :func:`thread_time_ns` to avoid the precision loss caused by the :class:`float` type. diff --git a/Misc/NEWS.d/next/Documentation/2021-03-04-22-53-03.bpo-43407.x570l5.rst b/Misc/NEWS.d/next/Documentation/2021-03-04-22-53-03.bpo-43407.x570l5.rst new file mode 100644 index 000000000000..615e3d016307 --- /dev/null +++ b/Misc/NEWS.d/next/Documentation/2021-03-04-22-53-03.bpo-43407.x570l5.rst @@ -0,0 +1,4 @@ +Clarified that a result from :func:`time.monotonic`, +:func:`time.perf_counter`, :func:`time.process_time`, or +:func:`time.thread_time` can be compared with the result from any following +call to the same function - not just the next immediate call.