python2.5多处理池

我有python2.5和多处理(从 http://code.google.com/p/python-multiprocessing/ )

这个简单的代码(从文档中获取)有时工作得很奇怪,有时还可以,但有时它抛出超时Ex或挂起我的Windows(Vista),只有重置帮助:)为什么会发生这种情况?

from multiprocessing import Pool

def f(x):
    print "fc",x
    return x*x
pool = Pool(processes=4)  
if __name__ == '__main__':
    result = pool.apply_async(f, (10,))     # evaluate "f(10)" asynchronously
    print result.get(timeout=3)           # prints "100" unless your computer is *very* slow