An embodiment of the invention provides a method for changing a multi-processor system from a performance mode to a safety mode while the system continues to run software. When an external event or exception occurs, context is switched from the performance mode to the safety mode. After context is switched, at least one pair of CPUs is synchronized to operate in the safety mode. In addition, a multi-processor system may be switched form the safety mode to the performance mode while the software continues to operate.