Julia 1.7.0-DEV.320
There is always one thread almost always 100% occupied on my machine. I have only a REPL running, and I called no function.
Maybe you have something in your startup.jl?
Found only one startup.jl, which is in my Julia pulled repo, which is also empty.
It turned out to be my jupyter-lab. Though there are only some markdown lines for one notebook only. Have to kill jupyter-lab when I am not using it.
jupyter-lab says that IJulia kernel for julia-1.7 is “untrusted”. Mine is totally not usable.
Downgrading to julia1.5.3 did the job. The CPU is not that busy any more.
Perhaps it is the problem from the combination of julia-1.7 and its IJulia.