The value in this file affects behavior of handling NMI (Non-Maskable Interrupt). When the value is non-zero, unknown NMI is trapped and then panic occurs. At that time, kernel debugging information is displayed on console. That can ease the process of diagnosing system hangs.
This function and oprofile share a NMI callback. Therefore this function cannot be enabled when oprofile is activated. And NMI watchdog will be disabled when the value in this file is set to non-zero.