python 输出日志跑不动 死锁现象

sp = subprocess.Popen(c_args, stderr=subprocess.PIPE)
sp.wait()
out = sp.stderr.readlines()
self.sl.dowrite(threading.currentThread().getName() + "_" + table_name, ''.join(out))

sp = subprocess.Popen(c_args, stderr=subprocess.PIPE)
out = sp.stderr.readlines()
sp.wait()
self.sl.dowrite(threading.currentThread().getName() + "_" + table_name, ''.join(out))

参考：
http://meisw.51099.com/show-348-1.html