google colab GPU processing become very slow after keras and tensorflow upgrade
You can reset your backend using the Runtime -> Reset all runtimes... menu item. (This is much faster than kill -9 -1, which will take some time to reconnect.)
I've upgrade my tensorflow and keras with this code:
!pip install tf-nightly-gpu-2.0-preview
Now every epoch of model learning cost 22 min which was 17 sec before this upgrade!!!
I did downgrade tensorflo and keras but it did not help!