Hey @albanD, thanks for your quick reply.
I install it via conda install pytorch torchvision -c pytorch.
And I didn’t set the threads by  torch.set_num_threads() or OMP_NUM_THREADS, so it should be the default value or setting.
BTW, set_num_threads() doesn’t work for me in any way, it’s always 1
In [2]: th.get_num_threads()
Out[2]: 1

In [3]: th.set_num_threads(2)

In [4]: th.get_num_threads()
Out[4]: 1