Storage access support for soft real-time applications

Wu, Joel C.; Brandt, Scott

doi:10.1109/rttas.2004.1317261

Cited by 8 publications

(4 citation statements)

References 23 publications

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“…Another thread of research on real-time disk scheduling is represented by Wu and Brandt [17]. Noting the increasing intelligence of disk drives, they have taken a feedback approach to scheduling disk requests.…”

Section: Related Workmentioning

confidence: 99%

Throttling On-Disk Schedulers to Meet Soft-Real-Time Requirements

Stanovich

Baker

Wang

2008

2008 IEEE Real-Time and Embedded Technology and Applications Symposium

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Many contemporary disk drives have built-in queues and schedulers. These features can improve I/O performance, by offloading work from the system's main processor, avoiding disk idle time, and taking advantage of vendor-specific disk characteristics. At the same time, they pose challenges for scheduling requests that have real-time requirements, since the operating system has less visibility and control over service times. While it may be possible for an operating system to obtain more predictable real-time performance by bypassing the on-disk queue and scheduler, the diversity and continuing evolution of disk drives make it difficult to extract the necessary detailed timing characteristics of a specific disk, and to generalize that approach to all hard drives. This paper demonstrates three techniques we developed in the Linux operating system to bound real-time request response times for disks with internal queues and schedulers. The first technique is to use the disk's built-in starvation prevention scheme. The second is to prevent requests from being sent to the disk when real-time requests are waiting to be served. The third is to limit the length of the on-disk queue in addition to the second technique. Our results show the ability to guarantee a wide range of desired response times while still allowing the disk to perform scheduling optimizations. These techniques can be generalized to disks from different vendors.

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Section: Related Workmentioning

confidence: 99%

Throttling On-Disk Schedulers to Meet Soft-Real-Time Requirements

Stanovich

Baker

Wang

2008

2008 IEEE Real-Time and Embedded Technology and Applications Symposium

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“…Storage performance is a function of the workload and the underlying device, each of which are complex and their interaction is non-trivial. The stateful nature of the disk [26] and the complexity of the internals of an array rendered this a difficult problem. Several works have appeared and tackle this problem in various forms [22,11,21,1].…”

Section: Ensuring Performancementioning

confidence: 99%

Ensuring Performance in Activity-Based File Relocation

Hong

Brandt

2007

2007 IEEE International Performance, Computing, and Communications Conference

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“…By limiting the rate of BE requests we supply the remainder of the disk bandwidth to multimedia tasks. Our previous work showed that bandwidth limiting is effective in managing multimedia disk allocations [11].…”

Section: Shaping Disk Bandwidthmentioning

confidence: 99%

<title>Automated QoS support for multimedia disk access</title>

Banachowski

Brandt

2005

SPIE Proceedings

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This paper describes the AutoQoS mechanism, which improves the timeliness of disk accesses for multimedia applications without requiring any explicit information about their constraints. Multimedia applications typically have periodic time constraints, meaning that they must complete data processing at periodic intervals in order to function correctly. This requirement extends to the disk system, because the application must access data on time in order to meet deadlines. By using Quality of Service algorithms for disk services, an application may receive enough bandwidth and isolation from other disk accesses to read data on time. Nevertheless, past approaches are restrictive because they require that disk bandwidth or deadlines be known and specified in advance. Our system infers from I/O behavior the bandwidth requirement of multimedia streams, and automatically adjusts allocations in order to provide Quality of Service without knowing the constraints or requiring intervention from the application.

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Storage access support for soft real-time applications

Abstract: Most research on QoS-aware

Cited by 8 publications

References 23 publications

Throttling On-Disk Schedulers to Meet Soft-Real-Time Requirements

Throttling On-Disk Schedulers to Meet Soft-Real-Time Requirements

Ensuring Performance in Activity-Based File Relocation

<title>Automated QoS support for multimedia disk access</title>

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