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arXiv 1402.4111cs.DS
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能量有效的非抢占式速度缩放算法

Energy-efficient algorithms for non-preemptive speed-scaling

Vincent Cohen-Addad, Zhentao Li, Claire Mathieu, Ioannis Millis

摘要:

我们改进了单处理器和多处理器情况下的节能速度调度问题的复杂性界限。节能已经成为一个主要的问题,因此重新审视传统的调度问题,考虑到能源消耗一直是调度社区在过去几年的议程的一部分。我们认为,能源最小化的速度缩放问题介绍了姚等。我们希望安排一组作业,每个发布日期,截止日期和工作量,在一组相同的处理器。处理器可以根据时间改变速度,并且它们消耗的能量是其速度的$α$次方。然后,目标是找到一个可行的时间表,最大限度地减少使用的总能量。我们表明,在设置与任意数量的处理器,所有的工作量是相等的,有一个$2(1+\varepsilon)(5(1+\varepsilon))^{α-1}\tilde{B}_α=O_α(1)$近似算法,其中$\tilde{B}_α$是广义贝尔数。这是求解该问题的第一个常数因子算法。该算法扩展到一般不等的处理器相关的工作量,直到在近似中丢失因子$(\frac{(1+r)r}{2})^α$,其中$r$是两个工作量之间的最大比率。然后,我们表明后一个问题是APX困难的,即使在特殊情况下,当所有的发布日期和最后期限是平等的,$r$是4。在单处理器情形下,我们引入了一个新的线性规划速度缩放公式,并证明了它的完整性间隙至多为$12^{α-1}$。作为推论,我们得到了一个$(12(1+\varepsilon))^{α-1}$近似算法,其中有一个单一的处理器,改善了以前的最佳界的$2^{α-1}(1+\varepsilon)^α\tilde{B}_α$时,$α\ge 25$。

英文摘要:

We improve complexity bounds for energy-efficient speed scheduling problems for both the single processor and multi-processor cases. Energy conservation has become a major concern, so revisiting traditional scheduling problems to take into account the energy consumption has been part of the agenda of the scheduling community for the past few years. We consider the energy minimizing speed scaling problem introduced by Yao et al. where we wish to schedule a set of jobs, each with a release date, deadline and work volume, on a set of identical processors. The processors may change speed as a function of time and the energy they consume is the $α$th power of its speed. The objective is then to find a feasible schedule which minimizes the total energy used. We show that in the setting with an arbitrary number of processors where all work volumes are equal, there is a $2(1+\varepsilon)(5(1+\varepsilon))^{α-1}\tilde{B}_α=O_α(1)$ approximation algorithm, where $\tilde{B}_α$ is the generalized Bell number. This is the first constant factor algorithm for this problem. This algorithm extends to general unequal processor-dependent work volumes, up to losing a factor of $(\frac{(1+r)r}{2})^α$ in the approximation, where $r$ is the maximum ratio between two work volumes. We then show this latter problem is APX-hard, even in the special case when all release dates and deadlines are equal and $r$ is 4. In the single processor case, we introduce a new linear programming formulation of speed scaling and prove that its integrality gap is at most $12^{α-1}$. As a corollary, we obtain a $(12(1+\varepsilon))^{α-1}$ approximation algorithm where there is a single processor, improving on the previous best bound of $2^{α-1}(1+\varepsilon)^α\tilde{B}_α$ when $α\ge 25$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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