nice, renice, and ps

1. Ensure that you have the httpd package installed on the system.

[root@localhost]# yum install httpd

2. Ensure the httpd service is NOT RUNNING.

[root@localhost]# systemctl stop httpd

3. Start the httpd service with the most favorable nice possible.

[root@localhost]# nice -n -20 httpd

4. View the current nice of the httpd service using the ps command and pgrep command together.

[root@localhost]# ps axo pid,comm,nice | grep httpd 

or 

[root@localhost]# ps axo pid,comm,nice --sort=--nice | grep httpd 

This will allow you to sort by nice level.

6. Renice all httpd processes and set the nice level to 0.

[root@localhost]# renice -n 0 $(pgrep httpd)