:: Determine which MPM running in apache

if you see worker.c, your apache running worker mpm, if you see prefork.c, apache running prefork.

 
:: Determine has apache worked mpm compiled

make sure you see worker.c on there.

 
:: How to change apache prefork mpm to worker mpm on linux centos

then restarting apache

 
:: Links
+ Google
+ CrisGilligan