Co-Scheduling of Hybrid Transactions on Multiprocessor Real-Time Database Systems

Abstract

Deriving deadlines and periods for update transactions and scheduling hybrid transactions have been recognized as an important issue in real-time database systems. Despite years of research, all existing techniques focus on assigning deadlines and periods for update transactions in uniprocessor systems and, thus, cannot be applied in multiprocessor systems. Two partitioned scheduling methods for hybrid transactions in multiprocessor systems are proposed in this paper, by developing existing scheduling methods for uniprocessor systems to multiprocessor environments. An effective strategy is proposed to improve the efficiencies of the proposed methods, under which the improvement of efficiency is at the price of the acceptance ratio of transaction sets. For addressing the low acceptance ratio of the improvement strategy, we propose a novel scheduling method. A set of experiments is conducted to test the performances of the proposed methods. To the best of our knowledge, this is the first paper for co-scheduling of hybrid transactions on multiprocessor platforms. INDEX TERMSReal-time database systems, multiprocessor, hybrid transactions, deadlines and periods, co-scheduling.

A Parameterized Formal Model for the Analysis of Preemption-Threshold Scheduling in Real-Time Systems

“…We have checked the different studied properties by applying the probability estimation algorithm implemented in SBIP with a confidence of 0.4 and a precision of 0.4. Table 5 illustrates the results obtained on a configuration of 4 tasks and where the task's parameters are configured according to the following order: T i (C i , D i , P i , θ i , CP i ), and are respectively T 1 (13,80,120,3,3,4), T 2 (4, 70, 80, 2, 4, 2), T 3 (5, 66, 110, 1, 4, 3) and T 4 (22,27,31,4,4,5).…”

“…Formal verification of time-critical systems which define a set of real-time constraints is both imperative and complex. Real-time systems very often consist of multiple components such as processors on which multiple tasks are executing concurrently [13]. The interferences between tasks are complex and very hard to detect by simulation, which makes formal analysis mandatory in order to obtain safe knowledge about the real behavior of the system.…”