Thanks for your reply.
My pytorch version is  '0.4.1.post2' and the version of h5py  is '2.8.0'.
My error encountered is :  when num_worker>1,

KeyError: 'Traceback (most recent call last):
File “/home/bjohnson/.anaconda/lib/python2.7/site-packages/torch/utils/data/dataloader.py”, line 55, in _worker_loop
samples = collate_fn([dataset[i] for i in batch_indices])
File “”, line 11, in getitem
File “h5py/_objects.pyx”, line 54, in h5py._objects.with_phil.wrapper
File “h5py/_objects.pyx”, line 55, in h5py._objects.with_phil.wrapper
File “/home/bjohnson/.anaconda/lib/python2.7/site-packages/h5py/_hl/group.py”, line 167, in getitem
oid = h5o.open(self.id, self._e(name), lapl=self._lapl)
File “h5py/_objects.pyx”, line 54, in h5py._objects.with_phil.wrapper
File “h5py/_objects.pyx”, line 55, in h5py._objects.with_phil.wrapper
File “h5py/h5o.pyx”, line 190, in h5py.h5o.open
KeyError: Unable to open object (bad object header version number)