Q. I've single CPU server system. If another CPU is added to my server, will CentOS Linux recognize it automatically on the next boot? Do I need to configure something?
A. If you are using SMP kernel, then Linux should detect 2nd CPU after reboot. Symmetric multiprocessing or SMP involves a multiprocessor computer architecture where two or more identical processors can connect to a single shared main memory. Most common multiprocessor systems today use an SMP architecture. In case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors.
SMP systems allow any processor to work on any task no matter where the data for that task are located in memory; with proper operating system support, SMP systems can easily move tasks between processors to balance the workload efficiently.
To see if the SMP kernel is installed on a system, execute the following command under CentOS:
# rpm -q kernel-smp
Most modern Linux distro by default installed SMP kernel.