The new 4.19 kernel is causing trouble

A "kworker" process is hogging my CPU. I have to go back to 4.18 kernel to resolve this issue.

UPDATE (01/24/2019)

The solution is amazingly simple. Follow this post:

1. Install perf;
2. sudo perf record -g -a sleep 10
3. sudo perf report

Scrolling down the records, it looks like the problem is related to my USB hub. Unplug the hub and the problem goes away. 

Good tmap examples

I learned a lot from this.

How to increase graph resolution in Rmarkdown and more

Very useful information here.