1. installing ubuntu 16-04 amd 64bit
2. installing realtime preempt-rt 4.19 by following command interminal (ctrl + Alt +T to open terminal):
	sudo apt-get update
	sudo apt-get dist-upgrade
	sudo apt-get install gdebi 
	sudo add-apt-repository ppa:danielrichter2007/grub-customizer
	sudo apt-get update
	sudo apt-get install grub-customizer
   Download realtime kernel:
	cd Downloads
	wget http://ftp.us.debian.org/debian/pool/main/l/linux/linux-image-4.9.0-13-rt-amd64_4.9.228-1_amd64.deb
	sudo gdebi linux-image-4.9.0-13-rt-amd64_4.9.228-1_amd64.deb
   Open grub-customizer --> general setting ---> change boot kernel to 4.9 --> save and reset
3. Open terminal and run "uname -a" to check what kernel we are using (it should be 4.9.0-13-rt-amd64 SMP PREEMPT RT)
4. Testing
	sudo apt-get install mesa-utils
   Run glxgears in several hours, open terminal and run command:	
	glxgears
   run more than 3 tabs and see