IISc Logo    Title

etd AT Indian Institute of Science >
Division of Electrical Sciences >
Computer Science and Automation (csa) >

Please use this identifier to cite or link to this item: http://hdl.handle.net/2005/639

Title: Time Management In Partitioned Systems
Authors: Kodancha, A Hariprasad
Advisors: Gopinath, K
Keywords: Operating System
Partitions
Time Management (Operating Systems)
Partitioned Systems - Time Management
Time Management - Algorithms
Tick-Based Timer Algorithms
One-Shot Timer Algorithms
Partitions (Computer System)
Firm Timer
ARINC-653
Submitted Date: Oct-2007
Series/Report no.: G21666
Abstract: Time management is one of the critical modules of safety-critical systems. Applications need strong assurance from the operating system that their hard real-time requirements are met. Partitioned system has recently evolved as a means to provide protection to safety critical applications running on an Avionics computer resource. Each partition has an application running strictly for a specified duration. These applications use the CPU on a cyclic basis. Applications running on a real-time systems request the service of time management in one way or the other. An application may request for a time-out while waiting for a resource, may voluntarily relinquish the CPU for some delay time or may have deadline before which it is expected to complete its tasks. These requests must be handled in a deterministic and accurate way with lower overheads. Time management within an operating system uses the hardware timers to service the time-out requests. The three well-known approaches for handling timer requests are tick-based, one-shot and firm timer. Traditionally tick-based has been the most popular approach that relies on periodic interrupt timer, although it has a poor accuracy. One-shot timer approach provides better accuracy as the timer interrupt can be generated exactly when required. Firm timers use soft timers in combination with one-shot timer wherein the expired timers are checked at strategic points in the kernel. The thesis compares the performance of these three approaches for partitioned systems and provides an insight about the suitability of the approaches. The thesis presents tick-based and one-shot timer algorithms that handle time-out requests of real-time applications running on a partitioned system by adhering to time partitioning rules. It compares the performance of these algorithms. It presents an one-shot timer algorithm named hierarchical multiple linked lists and the experimental results proves that the algorithm performs better than other conventional linked list based one-shot timer algorithms. The thesis also analyzes the timing behavior of real-time applications for partitioned systems. The hard real-time system under consideration is avionics system and an indigenously developed ARINC-653 compliant real-time operating system has been used to measure the performance.
URI: http://hdl.handle.net/2005/639
Appears in Collections:Computer Science and Automation (csa)

Files in This Item:

File Description SizeFormat
G21666.pdf812.71 kBAdobe PDFView/Open

Items in etd@IISc are protected by copyright, with all rights reserved, unless otherwise indicated.

 

etd@IISc is a joint service of SERC & IISc Library ||
Feedback
|| Powered by DSpace || Compliant to OAI-PMH V 2.0 and ETD-MS V 1.01