Issue #17914: Add os.cpu_count(). Patch by Yogesh Chaudhari, based on an

initial patch by Trent Nelson.

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():
     '''