Queuing model with interrupt enable points and its application to the analyses of suspend controls of disk units

We proposed a queuing model with interrupt enable points and applied this model to the analysis of suspend control for disk drives. To respond to the 24-hour operation of computer systems, there is a requirement to implement the control objectives of limiting the degradation of the response times to high-priority jobs like online jobs and guaranteeing the throughput of low-priority jobs such as batch jobs. To achieve the above control objectives in CPU resources, interrupt priority control is often applied. However, applying this control to the resources for data transfer is difficult. If an interrupt is generated at the timing except the specific timing during a data transfer processing, the data transfer process terminates abnormally. Suspend control detects the arrival of a high-priority job during each fixed service of a low-priority job and transfers control. We defined the opportunities to detect the arrival of a high-priority job as the interrupt enable points and modeled these controls. We evaluated the proposed model and determined that suspend control is an effective way to implement the above control objectives. © 2000 Scripta Technica, Syst Comp Jpn, 31(11): 51–59, 2000