gogus wrote on Sunday, November 18, 2018:
Thank you for the quick reply 
Of course, when I use polling, the cpu utilization will be much higher. My bare-metal program is event and interrupt driven so it should be more efficiency than that with freertos, shouldn’t it? With RTOS cpu has more work to do e.g. context switch.
The code included above is simple example of the problem. Of cource, the results are real for this example.