[unbit]

in both gunicorn and php you have to choose the number of workers/processes. Most of the time (unless you use php-fastcgi) the number of php processes is choosen by the sysadmin as it maps 1:1 with apache processes. The same is true for mod_wsgi. There is always some form of configuration independently by the load. One of the reasons for some users blaming at apache+mod_wsgi is because they maintain the default (bloated) apache configuration like php users/sysadmin tend to do.