Dynamic disk bandwidth management and metadata pre-fetching in a real-time file system

The authors focus on two practical considerations that arise in the design of a real-time file system. Firstly, disk bandwidth management should be dynamic, which in turn would allow a QoS manager to dynamically reallocate disk bandwidth to running applications based on their changing needs. Secondly, real-time access to file system data structures should be deterministic, in order to avoid unexpected latencies when accessing files from disk. These issues have implications to the design of the file system and to its schedulability analysis. They address both these problems and present an implementation in RTFS (Real-Time Filesystem Server), a real-time file system supporting disk bandwidth reservation running on top of the Real-Time Mach microkernel. Finally, quantitative comparisons of actual achieved file system bandwidth and response times are used to validate the approach.

[1]  Ragunathan Rajkumar,et al.  Real-time filesystems. Guaranteeing timing constraints for disk accesses in RT-Mach , 1997, Proceedings Real-Time Systems Symposium.

[2]  Daniel P. Siewiorek,et al.  A resource allocation model for QoS management , 1997, Proceedings Real-Time Systems Symposium.

[3]  Chung Laung Liu,et al.  Scheduling Algorithms for Multiprogramming in a Hard-Real-Time Environment , 1989, JACM.

[4]  Alan Burns,et al.  Fixed Priority Scheduling of Hard Real-time Multi-media Disk Traffic , 1994, Comput. J..

[5]  Hideyuki Tokuda,et al.  RT-IPC: An IPC Extension for Real-Time Mach , 1993, USENIX Microkernels and Other Kernel Architectures Symposium.

[6]  Abraham Silberschatz,et al.  Operating System Concepts , 1983 .

[7]  H. Garcia-Molina,et al.  Scheduling I/O requests with deadlines: A performance evaluation , 1990, [1990] Proceedings 11th Real-Time Systems Symposium.

[8]  Ragunathan Rajkumar,et al.  Synchronization in Real-Time Systems: A Priority Inheritance Approach , 1991 .

[9]  Ángel Viña,et al.  A preemptive priority-based disk I/O subsystem for the management of hard real-time disk traffic , 1997, Proceedings Ninth Euromicro Workshop on Real Time Systems.

[10]  Ragunathan Rajkumar,et al.  Synchronization in Real-Time Systems , 1991 .

[11]  Samuel J. Leffler,et al.  The design and implementation of the 4.3 BSD Unix operating system , 1991, Addison-Wesley series in computer science.

[12]  Shuichi Oikawa,et al.  Resource kernels: a resource-centric approach to real-time and multimedia systems , 2001, Electronic Imaging.

[13]  Lui Sha,et al.  Priority Inheritance Protocols: An Approach to Real-Time Synchronization , 1990, IEEE Trans. Computers.

[14]  D. B. Kirk,et al.  SMART (strategic memory allocation for real-time) cache design , 1989, [1989] Proceedings. Real-Time Systems Symposium.