map_reduce.py example: AttributeError: 'NoneType' object has no attribute 'eventDestroy'

When running examples/streams/map_reduce.py, I get the following:

elapsed time 0.12984609603881836
total bytes 167778304
total bytes 167778304
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC0572E8>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC057278>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC057208>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC057198>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC057128>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC0570B8>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC057048>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC04DEF0>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC04DF28>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'
Exception ignored in: <bound method Event.__del__ of <cupy.cuda.stream.Event object at 0x00000180AC057358>>
Traceback (most recent call last):
  File "cupy\cuda\stream.pyx", line 103, in cupy.cuda.stream.Event.__del__
AttributeError: 'NoneType' object has no attribute 'eventDestroy'

Conditions: CuPy Version : 7.2.0 CUDA Root : C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.0 CUDA Build Version : 10010 CUDA Driver Version : 10010 CUDA Runtime Version : 10010 cuBLAS Version : 10200 cuFFT Version : 10010 cuRAND Version : 10010 cuSOLVER Version : (10, 1, 0) cuSPARSE Version : 10010 NVRTC Version : (10, 1) cuDNN Build Version : 7605 cuDNN Version : 7605 NCCL Build Version : None NCCL Runtime Version : None

I’ve had the same results on two different computers (Windows and Linux, both cupy 7.2.0)

Code to reproduce cupy/examples/streams/map_reduce.py - no changes

[emcastillo]

Event did not had the fix applied …

[leofang]

Chatted with a few colleagues and it seems we’re not alone. h5py had similar shutdown issues (see e.g., https://github.com/h5py/h5py/issues/534). I was told they resolved by holding a hard reference to the needed module/function, but for the moment I can’t find the PR/code snippet that does this. Will ask if needed.

Another ref: https://docs.python.org/3/library/weakref.html#comparing-finalizers-with-del-methods Not sure whether this is a better, permanent solution or not.