util.py 文件源码

def _detect_ncpus():
    """Detect the number of effective CPUs in the system"""
    # Snippet taken from ParallelPython
    # For Linux, Unix and MacOS
    if hasattr(os, "sysconf"):
        if "SC_NPROCESSORS_ONLN" in os.sysconf_names:
            #Linux and Unix
            ncpus = os.sysconf("SC_NPROCESSORS_ONLN")
            if isinstance(ncpus, int) and ncpus > 0:
                return ncpus
        else:
            #MacOS X
            return int(os.popen2("sysctl -n hw.ncpu")[1].read())
    #for Windows
    if "NUMBER_OF_PROCESSORS" in os.environ:
        ncpus = int(os.environ["NUMBER_OF_PROCESSORS"])
        if ncpus > 0:
            return ncpus
    #return the default value
    return 1