Use a fraction internally in the _PyTime API to reduce the risk of
integer overflow: simplify the fraction using Greatest Common
Divisor (GCD). The fraction API is used by time functions:
perf_counter(), monotonic() and process_time().
For example, QueryPerformanceFrequency() usually returns 10 MHz on
Windows 10 and newer. The fraction SEC_TO_NS / frequency =
1_000_000_000 / 10_000_000 can be simplified to 100 / 1.
* Add _PyTimeFraction type.
* Add functions:
* _PyTimeFraction_Set()
* _PyTimeFraction_Mul()
* _PyTimeFraction_Resolution()
* No longer check "numer * denom <= _PyTime_MAX" in
_PyTimeFraction_Set(). _PyTimeFraction_Mul() uses _PyTime_Mul()
which handles integer overflow.
* Move _PyRuntimeState.time to _posixstate.ticks_per_second and
time_module_state.ticks_per_second.
* Add time_module_state.clocks_per_second.
* Rename _PyTime_GetClockWithInfo() to py_clock().
* Rename _PyTime_GetProcessTimeWithInfo() to py_process_time().
* Add process_time_times() helper function, called by
py_process_time().
* os.times() is now always built: no longer rely on HAVE_TIMES.
Use Argument Clinic for time.clock_gettime() and
time.clock_gettime_ns() functions.
Benchmark on time.clock_gettime_ns():
import time
import pyperf
runner = pyperf.Runner()
runner.timeit(
'clock_gettime_ns(CLOCK_MONOTONIC_COARSE)',
setup='import time; clock_gettime_ns=time.clock_gettime_ns; CLOCK_MONOTONIC_COARSE=6',
stmt='clock_gettime_ns(CLOCK_MONOTONIC_COARSE)')
Result on Linux with CPU isolation:
Mean +- std dev: [ref] 134 ns +- 1 ns -> [change] 55.7 ns +- 1.4 ns: 2.41x faster
Remove <ctype.h> in C files which don't use it; only sre.c and
_decimal.c still use it.
Remove _PY_PORT_CTYPE_UTF8_ISSUE code from pyport.h:
* Code added by commit b5047fd019
in 2004 for MacOSX and FreeBSD.
* Test removed by commit 52ddaefb6b
in 2007, since Python str type now uses locale independent
functions like Py_ISALPHA() and Py_TOLOWER() and the Unicode
database.
Modules/_sre/sre.c replaces _PY_PORT_CTYPE_UTF8_ISSUE with new
functions: sre_isalnum(), sre_tolower(), sre_toupper().
Remove unused includes:
* _localemodule.c: remove <stdio.h>.
* getargs.c: remove <float.h>.
* dynload_win.c: remove <direct.h>, it no longer calls _getcwd()
since commit fb1f68ed7c (in 2001).
Python.h no longer includes <time.h>, <sys/select.h> and <sys/time.h>
standard header files.
* Add <time.h> include to xxsubtype.c.
* Add <sys/time.h> include to posixmodule.c and semaphore.c.
* readline.c includes <sys/select.h> instead of <sys/time.h>.
* resource.c no longer includes <time.h> and <sys/time.h>.
Here we are doing no more than adding the value for Py_mod_multiple_interpreters and using it for stdlib modules. We will start checking for it in gh-104206 (once PyInterpreterState.ceval.own_gil is added in gh-104204).
Add `MS_WINDOWS_DESKTOP`, `MS_WINDOWS_APPS`, `MS_WINDOWS_SYSTEM` and `MS_WINDOWS_GAMES` preprocessor definitions to allow switching off functionality missing from particular API partitions ("partitions" are used in Windows to identify overlapping subsets of APIs).
CPython only officially supports `MS_WINDOWS_DESKTOP` and `MS_WINDOWS_SYSTEM` (APPS is included by normal desktop builds, but APPS without DESKTOP is not covered). Other configurations are a convenience for people building their own runtimes.
`MS_WINDOWS_GAMES` is for the Xbox subset of the Windows API, which is also available on client OS, but is restricted compared to `MS_WINDOWS_DESKTOP`. These restrictions may change over time, as they relate to the build headers rather than the OS support, and so we assume that Xbox builds will use the latest available version of the GDK.
An earlier commit only defined check_ticks_per_second() when HAVE_TIMES is defined. However, we also need it when HAVE_CLOCK is defined. This primarily affects Windows.
https://github.com/python/cpython/issues/81057
It combines PyImport_ImportModule() and PyObject_GetAttrString()
and saves 4-6 lines of code on every use.
Add also _PyImport_GetModuleAttr() which takes Python strings as arguments.
We're no longer using _Py_IDENTIFIER() (or _Py_static_string()) in any core CPython code. It is still used in a number of non-builtin stdlib modules.
The replacement is: PyUnicodeObject (not pointer) fields under _PyRuntimeState, statically initialized as part of _PyRuntime. A new _Py_GET_GLOBAL_IDENTIFIER() macro facilitates lookup of the fields (along with _Py_GET_GLOBAL_STRING() for non-identifier strings).
https://bugs.python.org/issue46541#msg411799 explains the rationale for this change.
The core of the change is in:
* (new) Include/internal/pycore_global_strings.h - the declarations for the global strings, along with the macros
* Include/internal/pycore_runtime_init.h - added the static initializers for the global strings
* Include/internal/pycore_global_objects.h - where the struct in pycore_global_strings.h is hooked into _PyRuntimeState
* Tools/scripts/generate_global_objects.py - added generation of the global string declarations and static initializers
I've also added a --check flag to generate_global_objects.py (along with make check-global-objects) to check for unused global strings. That check is added to the PR CI config.
The remainder of this change updates the core code to use _Py_GET_GLOBAL_IDENTIFIER() instead of _Py_IDENTIFIER() and the related _Py*Id functions (likewise for _Py_GET_GLOBAL_STRING() instead of _Py_static_string()). This includes adding a few functions where there wasn't already an alternative to _Py*Id(), replacing the _Py_Identifier * parameter with PyObject *.
The following are not changed (yet):
* stop using _Py_IDENTIFIER() in the stdlib modules
* (maybe) get rid of _Py_IDENTIFIER(), etc. entirely -- this may not be doable as at least one package on PyPI using this (private) API
* (maybe) intern the strings during runtime init
https://bugs.python.org/issue46541
The time module now creates its struct_time type as a heap
type using PyStructSequence_NewType(), rather than using a static
type.
* Add a module state to the time module: add traverse, clear and free
functions.
* Use PyModule_AddType().
* Remove the 'initialized' variable.
Rename Include/namespaceobject.h to
Include/internal/pycore_namespace.h.
The _testmultiphase extension is now built with the
Py_BUILD_CORE_MODULE macro defined to access _PyNamespace_Type.
object.c: remove unused "pycore_context.h" include.
On Windows, time.sleep() now uses a waitable timer which has a
resolution of 100 ns (10^-7 sec). Previously, it had a solution of 1
ms (10^-3 sec).
* On Windows, time.sleep() now calls PyErr_CheckSignals() before
resetting the SIGINT event.
* Add _PyTime_As100Nanoseconds() function.
* Complete and update time.sleep() documentation.
Co-authored-by: Livius <egyszeregy@freemail.hu>
Refactor pytime.c:
* Add pytime_from_nanoseconds() and pytime_as_nanoseconds(),
and use explicitly these functions
* Add two empty lines between functions
* PEP 7: add braces { ... }
* C99: declare variables where they are set
* Rename private functions to lowercase
* Rename error_time_t_overflow() to pytime_time_t_overflow()
* Rename win_perf_counter_frequency() to py_win_perf_counter_frequency()
* py_get_monotonic_clock(): add an assertion to detect overflow when
mach_absolute_time() unsigned uint64_t is casted to _PyTime_t
(signed int64_t).
_testcapi: use _PyTime_FromNanoseconds().
In Unix operating systems, time.sleep() now uses the clock_nanosleep() function,
if available, which allows to sleep for an interval specified with nanosecond precision.
Co-authored-by: Victor Stinner <vstinner@python.org>
time.time(), time.perf_counter() and time.monotonic() functions can
no longer fail with a Python fatal error, instead raise a regular
Python exception on failure.
Remove _PyTime_Init(): don't check system, monotonic and perf counter
clocks at startup anymore.
On error, _PyTime_GetSystemClock(), _PyTime_GetMonotonicClock() and
_PyTime_GetPerfCounter() now silently ignore the error and return 0.
They cannot fail with a Python fatal error anymore.
Add py_mach_timebase_info() and win_perf_counter_frequency()
sub-functions.
Co-authored-by: Lawrence D’Anna <lawrence_danna@apple.com>
* Add support for macOS 11 and Apple Silicon (aka arm64)
As a side effect of this work use the system copy of libffi on macOS, and remove the vendored copy
* Support building on recent versions of macOS while deploying to older versions
This allows building installers on macOS 11 while still supporting macOS 10.9.
On AIX, time.thread_time() is now implemented with thread_cputime()
which has nanosecond resolution, rather than
clock_gettime(CLOCK_THREAD_CPUTIME_ID) which has a resolution of 10 ms.
Calling setlocale(LC_CTYPE, "") on a system where GetACP() returns CP_UTF8 results in empty strings in _tzname[].
This causes time.tzname to be an empty string.
I have reported the bug to the UCRT team and will follow up, but it will take some time get a fix into production.
In the meantime one possible workaround is to temporarily change the locale by calling setlocale(LC_CTYPE, "C") before calling _tzset and restore the current locale after if the GetACP() == CP_UTF8 or CP_UTF7
@zooba
https://bugs.python.org/issue36779
Fix time.mktime() error handling on AIX for year before 1970.
Other changes:
* mktime(): rename variable 'buf' to 'tm'.
* _PyTime_localtime():
* Use "localtime" rather than "ctime" in the error message
(specific to AIX).
* Always initialize errno to 0 just in case if localtime_r()
doesn't set errno on error.
* On AIX, avoid abs() which is limited to int type.
* EINVAL constant is now always available.
Add Clang Memory Sanitizer build instrumentation to work around
false positives from the socket and time modules as well as skipping
a couple test_faulthandler tests.
* Fix test_mktime on AIX by adding code to get mktime to behave the
same way as it does on other *nix systems
* Fix test_pthread_getcpuclickid in AIX by adjusting the test case
expectations when running on AIX in 32-bit mode
Patch by Michael Felt.
* PyInit_time() now returns NULL if an exception is raised.
* Rename PyInit_timezone() to init_timezone(). "PyInit_" prefix is
a special prefix for function initializing a module.
init_timezone() doesn't initialize a module and the function is not
exported.
get_gmtoff() now returns time_t instead of int to fix the following
Visual Studio warning:
Modules\timemodule.c(1183): warning C4244: 'return':
conversion from 'time_t' to 'int', possible loss of data
Victor Stinner
Nikita Sobolev
Petr Viktorin
Serhiy Storchaka
Eric Snow
Max Bachmann
Christian Heimes
Kumar Aditya
Dong-hee Na
Livius
Ronald Oussoren
Jakub Kulík
Batuhan Taskaya
Russell Owen
Paulo Henrique Silva
Hai Shi
Dong-hee Na
vrajivk
Paul Monson
Matthias Bussonnier
pxinwr
Victor Stinner
Zackery Spytz
Joannah Nanjekye
Gregory P. Smith
Michael Felt