On the Soft Real-Time Optimality of Global EDF on Uniform Multiprocessors
On the Soft Real-Time Optimality of Global EDF on Uniform Multiprocessors
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DOI：
10.1109/rtss.2017.00037
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发表时间：
2017-12
期刊：
影响因子：
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通讯作者：
Kecheng Yang;James H. Anderson
中科院分区：
文献类型：
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作者：
Kecheng Yang;James H. Anderson
众所周知，全局最早截止日期优先(GEDF)调度器对于在相同的多处理器平台上执行的零星任务系统来说是软实时(SRT)最优的，无论任务执行是抢占还是非抢占的。对于任何可行的任务系统，这种最优化的概念都要求最后期限延误是可证明有界的。近年来，人们有兴趣将这些SRT最优性结果扩展到适用于处理器可能具有不同速度的统一的异质平台。然而，最近的研究表明，非抢占式GEDF在这样的平台上并不是SRT最优的。剩下的一个案例--先发制人的GEDF--后来被证明是相当难以解决的，而且多年来一直未结。在本文中，通过证明抢占式GEDF在统一平台上确实是SRT最优的来解决这种情况，只要使用一定的作业迁移策略。
It has long been known that the global earliest-deadlinefirst (GEDF) scheduler is soft real-time (SRT) optimal for sporadic task systems executing on identical multiprocessor platforms, regardless of whether task execution is preemptive or non-preemptive. This notion of optimality requires deadline tardiness to be provably bounded for any feasible task system. In recent years, there has been interest in extending these SRT optimality results to apply to uniform heterogeneous platforms, in which processors may have different speeds. However, it was recently shown that nonpreemptive GEDF is not SRT optimal on such platforms. The remaining case, preemptive GEDF, has turned out to be quite difficult to tackle and has remained open for a number of years. In this paper, this case is resolved by showing that preemptive GEDF is indeed SRT optimal on uniform platforms, provided a certain job migration policy is used.