Non-clairvoyant Scheduling for Weighted Flow Time and Energy

نویسندگان

  • Sze-Hang Chan
  • Tak-Wah Lam
  • Lap-Kei Lee
  • Hing-Fung Ting Pan Zhang
  • P. ZHANG
چکیده

We consider the online scheduling problem of minimizing total weighted flow time plus energy in the dynamic speed scaling model, where a processor can scale its speed dynamically between 0 and some maximum speed T . In the past few years this problem has been studied extensively under the clairvoyant setting, which requires the size of a job to be known at release time [1, 4, 5, 8, 15, 18–20]. For the non-clairvoyant setting, despite its practical importance, the progress is relatively limited. Only recently an online algorithm LAPS is known to be O(1)-competitive for minimizing (unweighted) flow time plus energy in the infinite speed model (i.e., T = ∞) [11, 12]. This paper makes two contributions to the non-clairvoyant scheduling. First, we resolve the open problem that the unweighted result of LAPS can be extended to the more realistic model with bounded maximum speed. Second, we show that another non-clairvoyant algorithm WRR is O(1)-competitive when weighted flow time is concerned. Note that WRR is not as efficient as LAPS for scheduling unweighted jobs as WRR has a much bigger constant hidden in its competitive ratio. ∗This is a corrected version of a paper with the same title in CATS 2010 [14]; in particular, Lemmas 2 and 4 of Section 3 and the ordering of jobs in the potential analysis of Section 4 were given incorrectly before and are fixed in this version. On the other hand, the conjecture, given in Section 5, about the generalization of LAPS to the weighted setting has recently been resolved [13]. †Research is partially supported by HKU Grant 21476018. ‡Research is partially supported by NSFC Grant 60970003. c © 2011 Sze-Hang Chan, Tak-Wah Lam, Lap-Kei Lee, Hing-Fung Ting, and Peng Zhang ©cc Licensed under a Creative Commons Attribution License DOI: 10.4086/cjtcs.2011.001 S.H. CHAN, T.W. LAM, L.K. LEE, H.F. TING, AND P. ZHANG

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Non-clairvoyant Scheduling for Weighted Flow Time and Energy on Speed Bounded Processors

We consider the online scheduling problem of minimizing total weighted flow time plus energy on a processor that can scale its speed dynamically between 0 and some maximum speed T . In the past few years this problem has been studied extensively under the clairvoyant setting, which requires the size of a job to be known when it is released [1, 4, 5, 8, 12, 15, 16, 17]. For the non-clairvoyant s...

متن کامل

Non-clairvoyant Speed Scaling for Weighted Flow Time

We study online job scheduling on a processor that can vary its speed dynamically to manage its power. We attempt to extend the recent success in analyzing total unweighted flow time plus energy to total weighted flow time plus energy. We first consider the non-clairvoyant setting where the size of a job is only known when the job finishes. We show an online algorithm WLAPS that is 8α-competiti...

متن کامل

Scheduling heterogeneous processors isn't as easy as you think

We consider preemptive online scheduling algorithms to minimize the total weighted/unweighted flow time plus energy for speed-scalable heterogeneous multiprocessors. We show that the well-known priority scheduling algorithms Highest Density First, Weighted Shortest Elapsed Time First, and Weighted Late Arrival Processor Sharing, are not O(1)-speed O(1)-competitive for the objective of weighted ...

متن کامل

Speed Scaling Functions for Flow Time Scheduling Based on Active Job Count

We study online scheduling to minimize flow time plus energy usage in the dynamic speed scaling model. We devise new speed scaling functions that depend on the number of active jobs, replacing the existing speed scaling functions in the literature that depend on the remaining work of active jobs. The new speed functions are more stable and also more efficient. They can support better job select...

متن کامل

Non-Clairvoyant Online Scheduling to Minimize Energy

Scheduling multiple jobs released over time on a single machine with adjustable speed is a fundamental and well-studied problem with varied applications both in classical domains such as scheduling jobs in operating systems and in emerging disciplines such as data center management, green computing, etc. The typical objective in such scheduling problems is two-fold: to minimize the flow-time of...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2011