A firm real-time system implementation using commercial off-the-shelf hardware and free software

Srinivasan, Balaji; Pather, Shaun; Hill, R.M.; Ansari, Farheen Fatma; Niehaus, D.

doi:10.1109/rttas.1998.683194

Cited by 64 publications

(46 citation statements)

References 4 publications

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“…Since HALMPS uses the real-time clock-a hardware device found on all modern PC motherboards-to generate clock interrupts, the advanced programmable interrupt controller (APIC)-another device found on all modern PCs-is left unused and a device driver could be written that uses the APIC to provide precise interrupts. This has been done for other general-purpose operating systems such as Linux [80].…”

Section: Overhead Of High-frequency Timer Interruptsmentioning

confidence: 99%

Using Hierarchical Scheduling to Support Soft Real-Time Applications in General-Purpose Operating Systems

Stankovic¹,

Regehr²

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The CPU schedulers in general-purpose operating systems are designed to provide fast response time for interactive applications and high throughput for batch applications. The heuristics used to achieve these goals do not lend themselves to scheduling real-time applications, nor do they meet other scheduling requirements such as coordinating scheduling across several processors or machines, or enforcing isolation between applications, users, and administrative domains. Extending the scheduling subsystems of general-purpose operating systems in an ad hoc manner is time consuming and requires considerable expertise as well as source code to the operating system. Furthermore, once extended, the new scheduler may be as inflexible as the original.The thesis of this dissertation is that extending a general-purpose operating system with a general, heterogeneous scheduling hierarchy is feasible and useful. A hierarchy of schedulers generalizes the role of CPU schedulers by allowing them to schedule other schedulers in addition to scheduling threads. A general, heterogeneous scheduling hierarchy is one that allows arbitrary (or nearly arbitrary) scheduling algorithms throughout the hierarchy. In contrast, most of the previous work on hierarchical scheduling has imposed restrictions on the schedulers used in part or all of the hierarchy.This dissertation describes the Hierarchical Loadable Scheduler (HLS) architecture, which permits schedulers to be dynamically composed in the kernel of a general-purpose operating system. The most important characteristics of HLS, and the ones that distinguish it from previous work, are that it has demonstrated that a hierarchy of nearly arbitrary schedulers can be efficiently implemented in a general-purpose operating system, and that the behavior of a hierarchy of soft real-time schedulers can be reasoned about in order to provide guaranteed scheduling behavior to application threads. The flexibility afforded by HLS permits scheduling behavior to be tailored to meet complex requirements without encumbering users who have modest requirements with the performance and administrative costs of a complex scheduler.Contributions of this dissertation include the following.(1) The design, prototype implementation, and performance evaluation of HLS in Windows 2000. (2) A system of guarantees for scheduler composition that permits reasoning about the scheduling behavior of a hierarchy of soft real-time schedulers. Guarantees assure users that application requirements can be met throughout the lifetime of the application, and also provide application developers with a model of CPU allocation to which they can program. (3) The design, implementation, and evaluation of two augmented CPU reservation schedulers, which provide increase scheduling predictability when low-level operating system activity steals time from applications. iv AcknowledgmentsFirst of all, many thanks to my advisor Jack Stankovic for being supportive of me and my work, for giving me enough rope but not too much, for pushi...

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Section: Overhead Of High-frequency Timer Interruptsmentioning

confidence: 99%

Using Hierarchical Scheduling to Support Soft Real-Time Applications in General-Purpose Operating Systems

Stankovic¹,

Regehr²

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“…There is another interface, syscall_wait_for_interval(), to wait for a specific time interval if the task is not periodic. In fact, most Linuxbased real-time operating systems (Beal et al, 2000;Calandrino et al, 2006;Faggioli et al, 2009;Oikawa and Rajkumar, 1999;Srinivasan et al, 1998) provide a similar set of programming interfaces. Hence, the CPU scheduler only needs to set a new value for the cpus_allowed mask for the dispatched task, and call the migration thread supported by the Linux kernel, to migrate the task on to an appropriate processor.…”

Section: Prototype Implementationmentioning

confidence: 99%

FPSL, FPCL and FPZL schedulability analysis

Davis

Kato

2012

Real-Time Syst

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This paper presents the Fixed Priority until Static Laxity (FPSL), Fixed Priority until Critical Laxity (FPCL) and Extended versionThis paper builds on the paper "FPZL Schedulability Analysis" by Davis and Burns (2011b) published in the proceedings of RTAS 2011. This paper extends Davis and Burns (2011b) analysis to cover the FPSL and FPCL scheduling algorithms as well as FPZL. The analysis given in this paper is a superset of that provided for FPZL and reduces to it if the laxity threshold of each task is set to zero. In this paper, the experimental evaluation has been extended to include schedulability tests for FPSL (which also apply to FPCL) and simulation of FPCL as well as FPZL. We also report on a prototype implementation of FPCL and FPZL in a Linux kernel, running on an Intel Core 2 Quad processor (Q9650).

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“…We have implemented a Real-Time Scheduling Service (RTSS) in 'C', on top of the KU RealTime system (KURT) (Srinivasan et al 1998) that adds real-time functionality to Linux. First, the RTSS provides an interface between the agents and the system timers, allowing agents to: (1) query the operating system about the current time; (2) ask the RTSS to notify them after the passage of certain length of time; and (3) ask the RTSS to ping them at fixed time intervals.…”

Section: Cpu Resource Allocationmentioning

confidence: 99%

A Negotiation-Based Coalition Formation Model for Agents with Incomplete Information and Time Constraints

Soh¹

2002

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A firm real-time system implementation using commercial off-the-shelf hardware and free software

Cited by 64 publications

References 4 publications

Using Hierarchical Scheduling to Support Soft Real-Time Applications in General-Purpose Operating Systems

Using Hierarchical Scheduling to Support Soft Real-Time Applications in General-Purpose Operating Systems

FPSL, FPCL and FPZL schedulability analysis

A Negotiation-Based Coalition Formation Model for Agents with Incomplete Information and Time Constraints

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