Lesson 1 My 7 line code runs very slowly and showed this warning:WARNING (theano.gof.compilelock): Overriding existing lock by dead process '2811' (I am process '3264')?

I runned lesson1.ipynb on gcloud with gpu k80.
my software version :
google cloud k80
ubuntu 16.04
keras 1.2.1
theano 0.9.0

When I click run all , my code almost stop in the 7 code with a warning, it seems it will take hours to run this 7 line code.
How many time do you run this 7 line code here and get the result? some minutes or hours or seconds?
Below is the screen shot: