Throttling On-Disk Schedulers to Meet Soft-Real-Time Requirements
Source: Florida State University
To achieve better throughput, many hard drive manufacturers use internal queues and scheduling to take advantage of vendor-specific characteristics and knowledge. While this trend seems promising, the control of service time from the view of the operating system is weakened, posing challenges for scheduling requests that have real-time requirements. Also, the diversity of disk drives makes extracting detailed timing characteristics and its generalization for all hard drives very difficult. This paper demonstrates three techniques the authors developed under Linux to bound real-time request response times for disks with internal queues and schedulers.