kernel restart much slower on spyder 4

[Rafael Jaimes]

I know kernel restart is a costly task and locks up the IDE, however it is very useful for my daily development.

What i have noticed however, is that Spyder 3 took about 3-4 seconds to restart the kernel on my system. Spyder 4 takes about 7-8 seconds. I have tried several rudimentary benchmarks by uninstalling and reinstalling different Spyder versions and making sure the remainder of the conda env is the same regarding the other packages. Any idea what has changed between Spyder 3 and 4 to make the kernel restarts take so much longer?

Example use cases for restarting kernel:

1. When training a model in TF and the GPU memory fills up, it's the easiest/fastest way to empty the GPU memory.

2. Kafka are two examples of applications that continue background processes in the interpreter that can't be stopped with Ctrl+C. Restarting the kernel removes all traces of them.