"The new MPM is called Perchild, and it is based on the Dexter MPM. This means that a set number of child processes are created and each process has a dynamic number of threads. In this MPM it is possible to specify User and Group IDs for clusters of child process. Then, each virtual host is assigned to run in a specific cluster of child processes. If no cluster of child processes is specified, then the virtual host is run with the default User and Group Ids."