Ruby infinite loop causes 100% cpu load

Question

I implemented some code, which runs in a loop:

loop do
   ..
end

In that loop, I handle keypresses with Curses library. If I press N and entered something, I start a new Thread, which counts time( loop do .. end again)

The question is, why loop or while true causes 100% cpu load on one of the cpu cores? Is the problem actaully in loop?

Is there a way to do infinite loop with lower cpu consumption in ruby?

The full sources available here

UPD - Strace

$ strace -c -p 5480
Process 5480 attached - interrupt to quit
^CProcess 5480 detached
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
51.52    0.002188           0    142842           ioctl
24.21    0.001028           0     71421           select
14.22    0.000604           0     47614           gettimeofday
10.05    0.000427           0     47614           rt_sigaction
0.00    0.000000           0        25           write
0.00    0.000000           0        16           futex
------ ----------- ----------- --------- --------- ----------------
100.00    0.004247                309532           total

Answer 1

After some thinking and suggestions from user2246674 I managed to resolve the issue. It was not inside the threads, it was the main loop.

I had such code inside the main loop:

  c = Curses.getch
  unless c.nil? 
     # input handling

After adding sleep 1 to else problem was resolved. It does nothing when there's no input from Curses, then checks again in one second, and this stops it from actively polling STDIN and generating high CPU load