如果你对当前进程可用处理器的数量感兴趣，首先需要检查cpuset。否则（或者如果cpuset没有被使用），在Python 2.6及以上版本中，multiprocessing.cpu_count() 是正确的方法。在较旧的Python版本中，以下方法会退回到一些替代方法：

import os
import re
import subprocess
def available_cpu_count():
    """ Number of available virtual or physical CPUs on this system, i.e.
    user/real as output by time(1) when called with an optimally scaling
    userspace-only program"""
    # cpuset
    # cpuset may restrict the number of *available* processors
    try:
        m = re.search(r'(?m)^Cpus_allowed:\s*(.*)$',
                      open('/proc/self/status').read())
        if m:
            res = bin(int(m.group(1).replace(',', ''), 16)).count('1')
            if res > 0:
                return res
    except IOError:
        pass
    # Python 2.6+
    try:
        import multiprocessing
        return multiprocessing.cpu_count()
    except (ImportError, NotImplementedError):
        pass
    # https://github.com/giampaolo/psutil
    try:
        import psutil
        return psutil.cpu_count()   # psutil.NUM_CPUS on old versions
    except (ImportError, AttributeError):
        pass
    # POSIX
    try:
        res = int(os.sysconf('SC_NPROCESSORS_ONLN'))
        if res > 0:
            return res
    except (AttributeError, ValueError):
        pass
    # Windows
    try:
        res = int(os.environ['NUMBER_OF_PROCESSORS'])
        if res > 0:
            return res
    except (KeyError, ValueError):
        pass
    # jython
    try:
        from java.lang import Runtime
        runtime = Runtime.getRuntime()
        res = runtime.availableProcessors()
        if res > 0:
            return res
    except ImportError:
        pass
    # BSD
    try:
        sysctl = subprocess.Popen(['sysctl', '-n', 'hw.ncpu'],
                                  stdout=subprocess.PIPE)
        scStdout = sysctl.communicate()[0]
        res = int(scStdout)
        if res > 0:
            return res
    except (OSError, ValueError):
        pass
    # Linux
    try:
        res = open('/proc/cpuinfo').read().count('processor\t:')
        if res > 0:
            return res
    except IOError:
        pass
    # Solaris
    try:
        pseudoDevices = os.listdir('/devices/pseudo/')
        res = 0
        for pd in pseudoDevices:
            if re.match(r'^cpuid@[0-9]+$', pd):
                res += 1
        if res > 0:
            return res
    except OSError:
        pass
    # Other UNIXes (heuristic)
    try:
        try:
            dmesg = open('/var/run/dmesg.boot').read()
        except IOError:
            dmesgProcess = subprocess.Popen(['dmesg'], stdout=subprocess.PIPE)
            dmesg = dmesgProcess.communicate()[0]
        res = 0
        while '\ncpu' + str(res) + ':' in dmesg:
            res += 1
        if res > 0:
            return res
    except OSError:
        pass
    raise Exception('Can not determine number of CPUs on this system')

如果您的 python 版本大于等于 2.6，那么您可以简单地使用：

import multiprocessing
multiprocessing.cpu_count()

要了解更多信息，请访问以下链接：

http://docs.python.org/library/multiprocessing.html#multiprocessing.cpu_count