A computer system includes a host and a storage device. The host provides an input/output request (IO request). The storage device receives the IO request from the host and sends an interrupt informing input/output completion (IO completion) to the host after completing the IO request. The host adjusts the number of generated interrupts of the storage device using the number of delayed IOs. The computer system may adaptively control interrupt generation of the storage device based on a load status of a CPU or the number of delayed IOs. The interrupt generation of the storage device may be adjusted to obtain a CPU gain without loss of performance or processing time of the computer system.