The file that can be used for changing priority levels is /etc/security/limits.conf file, but it requires the following for changing the nice level:
Code:
username hard|soft priority #
Here
username is the USER field in top,
hard is a hard priority while
soft is a soft priority, and
# is the value for the priority.
The issue is that httpd is initiated as root user and then runs as nobody. If you try to set the level for nobody, it doesn't work and, if you set the level for root, it's going to basically impact all root processes.
As for FCGI, I don't see any available options for this on the Apache directives page for it:
https://httpd.apache.org/mod_fcgid/mod/mod_fcgid.html
I'm not saying it isn't possible to do it, but I am saying I cannot see a way currently that what you are wanting to achieve could be done.