This directory is used to set IRQ to CPU affinity, which allows the system to connect a particular IRQ to only one CPU. Alternatively, it can exclude a CPU from handling any IRQs.
Each IRQ has its own directory, allowing for the individual configuration of each IRQ. The
/proc/irq/prof_cpu_mask file is a bitmask that contains the default values for the
smp_affinity file in the IRQ directory. The values in
smp_affinity specify which CPUs handle that particular IRQ.
For more information about the
/proc/irq/ directory, see the following installed documentation: