From 44feda3cd0454cd00028e09f3151de67e8aad76f Mon Sep 17 00:00:00 2001 From: Charles-Francois Natali Date: Mon, 20 May 2013 14:40:46 +0200 Subject: [PATCH] Issue #17914: Add os.cpu_count(). Patch by Yogesh Chaudhari, based on an initial patch by Trent Nelson. --- Doc/library/multiprocessing.rst | 3 ++ Doc/library/os.rst | 11 ++++-- Lib/multiprocessing/__init__.py | 27 ++----------- Lib/test/test_os.py | 10 +++++ Misc/NEWS | 3 ++ Modules/posixmodule.c | 68 +++++++++++++++++++++++++++++++++ 6 files changed, 95 insertions(+), 27 deletions(-) diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst index 1c18062f8d3..2562e308be5 100644 --- a/Doc/library/multiprocessing.rst +++ b/Doc/library/multiprocessing.rst @@ -702,6 +702,9 @@ Miscellaneous Return the number of CPUs in the system. May raise :exc:`NotImplementedError`. + .. seealso:: + :func:`os.cpu_count` + .. function:: current_process() Return the :class:`Process` object corresponding to the current process. diff --git a/Doc/library/os.rst b/Doc/library/os.rst index 4ab5ebd4afc..137fd42986f 100644 --- a/Doc/library/os.rst +++ b/Doc/library/os.rst @@ -3155,10 +3155,6 @@ operating system. Return the set of CPUs the process with PID *pid* (or the current process if zero) is restricted to. - .. seealso:: - :func:`multiprocessing.cpu_count` returns the number of CPUs in the - system. - .. _os-path: @@ -3196,6 +3192,13 @@ Miscellaneous System Information Availability: Unix. +.. function:: cpu_count() + + Return the number of CPUs in the system. Returns None if undetermined. + + .. versionadded:: 3.4 + + .. function:: getloadavg() Return the number of processes in the system run queue averaged over the last diff --git a/Lib/multiprocessing/__init__.py b/Lib/multiprocessing/__init__.py index b5f16d78f43..b42613f8c2d 100644 --- a/Lib/multiprocessing/__init__.py +++ b/Lib/multiprocessing/__init__.py @@ -85,30 +85,11 @@ def cpu_count(): ''' Returns the number of CPUs in the system ''' - if sys.platform == 'win32': - try: - num = int(os.environ['NUMBER_OF_PROCESSORS']) - except (ValueError, KeyError): - num = 0 - elif 'bsd' in sys.platform or sys.platform == 'darwin': - comm = '/sbin/sysctl -n hw.ncpu' - if sys.platform == 'darwin': - comm = '/usr' + comm - try: - with os.popen(comm) as p: - num = int(p.read()) - except ValueError: - num = 0 - else: - try: - num = os.sysconf('SC_NPROCESSORS_ONLN') - except (ValueError, OSError, AttributeError): - num = 0 - - if num >= 1: - return num - else: + num = os.cpu_count() + if num is None: raise NotImplementedError('cannot determine number of cpus') + else: + return num def freeze_support(): ''' diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py index 3a38285b571..65d3c3bf6e3 100644 --- a/Lib/test/test_os.py +++ b/Lib/test/test_os.py @@ -2216,6 +2216,15 @@ class OSErrorTests(unittest.TestCase): else: self.fail("No exception thrown by {}".format(func)) +class CPUCountTests(unittest.TestCase): + def test_cpu_count(self): + cpus = os.cpu_count() + if cpus is not None: + self.assertIsInstance(cpus, int) + self.assertGreater(cpus, 0) + else: + self.skipTest("Could not determine the number of CPUs") + @support.reap_threads def test_main(): support.run_unittest( @@ -2246,6 +2255,7 @@ def test_main(): TermsizeTests, OSErrorTests, RemoveDirsTests, + CPUCountTests, ) if __name__ == "__main__": diff --git a/Misc/NEWS b/Misc/NEWS index 1c54d33f5c9..541a424322b 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -99,6 +99,9 @@ Core and Builtins Library ------- +- Issue #17914: Add os.cpu_count(). Patch by Yogesh Chaudhari, based on an + initial patch by Trent Nelson. + - Issue #17980: Fix possible abuse of ssl.match_hostname() for denial of service using certificates with many wildcards (CVE-2013-2099). diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c index cb72bf028b0..c24e1624112 100644 --- a/Modules/posixmodule.c +++ b/Modules/posixmodule.c @@ -113,6 +113,18 @@ corresponding Unix manual entries for more information on calls."); #include #endif +#ifdef __hpux +#include +#endif + +#if defined(__DragonFly__) || \ + defined(__OpenBSD__) || \ + defined(__FreeBSD__) || \ + defined(__NetBSD__) || \ + defined(__APPLE__) +#include +#endif + #if defined(MS_WINDOWS) # define TERMSIZE_USE_CONIO #elif defined(HAVE_SYS_IOCTL_H) @@ -10302,6 +10314,60 @@ get_terminal_size(PyObject *self, PyObject *args) } #endif /* defined(TERMSIZE_USE_CONIO) || defined(TERMSIZE_USE_IOCTL) */ +PyDoc_STRVAR(posix_cpu_count__doc__, +"cpu_count() -> integer\n\n\ +Return the number of CPUs in the system, or None if this value cannot be\n\ +established."); + +#if defined(__DragonFly__) || \ + defined(__OpenBSD__) || \ + defined(__FreeBSD__) || \ + defined(__NetBSD__) || \ + defined(__APPLE__) +static long +_bsd_cpu_count(void) +{ + long ncpu = 0; + int mib[2]; + size_t len = sizeof(int); + + mib[0] = CTL_HW; + mib[1] = HW_NCPU; + if (sysctl(mib, 2, &ncpu, &len, NULL, 0) == 0) + return ncpu; + else + return 0; +} +#endif + +static PyObject * +posix_cpu_count(PyObject *self) +{ + long ncpu = 0; +#ifdef MS_WINDOWS + SYSTEM_INFO sysinfo; + GetSystemInfo(&sysinfo); + ncpu = sysinfo.dwNumberOfProcessors; +#elif defined(__hpux) + ncpu = mpctl(MPC_GETNUMSPUS, NULL, NULL); +#elif defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN) + ncpu = sysconf(_SC_NPROCESSORS_ONLN); +#elif defined(__APPLE__) + size_t len = sizeof(int); + if (sysctlnametomib("hw.logicalcpu", &ncpu, &len, NULL, 0) != 0) + ncpu = _bsd_cpu_count(); +#elif defined(__DragonFly__) || \ + defined(__OpenBSD__) || \ + defined(__FreeBSD__) || \ + defined(__NetBSD__) + ncpu = _bsd_cpu_count(); +#endif + if (ncpu >= 1) + return PyLong_FromLong(ncpu); + else + Py_RETURN_NONE; +} + static PyMethodDef posix_methods[] = { {"access", (PyCFunction)posix_access, @@ -10747,6 +10813,8 @@ static PyMethodDef posix_methods[] = { #if defined(TERMSIZE_USE_CONIO) || defined(TERMSIZE_USE_IOCTL) {"get_terminal_size", get_terminal_size, METH_VARARGS, termsize__doc__}, #endif + {"cpu_count", (PyCFunction)posix_cpu_count, + METH_NOARGS, posix_cpu_count__doc__}, {NULL, NULL} /* Sentinel */ };