Rewriting History to Exploit Gain Time

TY - CONF

T1 - Rewriting History to Exploit Gain Time

AU - Bernat, Guillem

AU - Broster, Ian

AU - Burns, Alan

N1 - Lisbon, Portugal December 05-December 08 ISBN: 0-7695-2247-5

PY - 2004

Y1 - 2004

N2 - With modern processors and more dynamic application requirements it is becoming increasingly difficult to produce tight upper bounds on the worst-case execution time of real-time tasks. As a result, at run-time, considerable spare CPU capacity (termed gain time) becomes available that must be usefully employed if cost effective real-time systems are to be engineered. In this paper we introduce a scheme by which gain time is exploited by retrospectively reassigning execution time from a task?s own budget to the gain time that later become available. As a result of changing the system?s execution history, spare capacity is immediately reallocated and hence preserved. The proposed scheme is shown to work with fixed priority dispatching, the use of servers to provide temporal firewalls, and other capacity sharing approaches. Evaluations are provided via simulations.

AB - With modern processors and more dynamic application requirements it is becoming increasingly difficult to produce tight upper bounds on the worst-case execution time of real-time tasks. As a result, at run-time, considerable spare CPU capacity (termed gain time) becomes available that must be usefully employed if cost effective real-time systems are to be engineered. In this paper we introduce a scheme by which gain time is exploited by retrospectively reassigning execution time from a task?s own budget to the gain time that later become available. As a result of changing the system?s execution history, spare capacity is immediately reallocated and hence preserved. The proposed scheme is shown to work with fixed priority dispatching, the use of servers to provide temporal firewalls, and other capacity sharing approaches. Evaluations are provided via simulations.

M3 - Paper

SP - 328

EP - 335

ER -