Minimizing the flow time without migration

Baruch Awerbuch, Yossi Azar, Stefano Leonardi, Oded Regev

Research output: Contribution to journalArticle

Abstract

We consider the classical problem of scheduling jobs in a multiprocessor setting in order to minimize the flow time (total time in the system). The performance of the algorithm, both in offline and online settings, can be significantly improved if we allow preemption, i.e., interrupt a job and later continue its execution, perhaps migrating it to a different machine. Preemption is inherent to make a scheduling algorithm efficient. While in the case of a single processor most operating systems can easily handle preemptions, migrating a job to a different machine results in a huge overhead. Thus, it is not commonly used in most multiprocessor operating systems. The natural question is whether migration is an inherent component for an efficient scheduling algorithm in either the online or offline setting. Leonardi and Raz [Proceedings of the Twenty-Ninth Annual ACM Symposium on Theory of Computing, El Paso, TX, 1997, pp. 110-119] showed that the well-known algorithm, shortest remaining processing time (SRPT), performs within a logarithmic factor of the optimal offline algorithm. Note that SRPT must use both preemption and migration to schedule the jobs. It is not known if better approximation factors can be reached and thus SRPT, although it is an online algorithm, becomes the best known algorithm in the offline setting. In fact, in the online setting, Leonardi and Raz showed that no algorithm can achieve a better bound. Without migration, no (offline or online) approximations are known. This paper introduces a new algorithm that does not use migration, works online, and is just as effective (in terms of approximation ratio) as the best known offline algorithm that uses migration.

Original languageEnglish (US)
Pages (from-to)1370-1382
Number of pages13
JournalSIAM Journal on Computing
Volume31
Issue number5
DOIs
StatePublished - May 2002

Fingerprint

Flow Time
Migration
Preemption
Scheduling Algorithm
Operating Systems
Approximation
Scheduling algorithms
Job Scheduling
Processing
Multiprocessor Systems
Online Algorithms
Multiprocessor
Optimal Algorithm
Annual
Logarithmic
Schedule
Continue
Efficient Algorithms
Minimise
Computing

Keywords

  • Approximation
  • Flow time
  • Migration
  • Online
  • Scheduling

ASJC Scopus subject areas

  • Computational Theory and Mathematics
  • Applied Mathematics
  • Theoretical Computer Science

Cite this

Minimizing the flow time without migration. / Awerbuch, Baruch; Azar, Yossi; Leonardi, Stefano; Regev, Oded.

In: SIAM Journal on Computing, Vol. 31, No. 5, 05.2002, p. 1370-1382.

Research output: Contribution to journalArticle

Awerbuch, Baruch ; Azar, Yossi ; Leonardi, Stefano ; Regev, Oded. / Minimizing the flow time without migration. In: SIAM Journal on Computing. 2002 ; Vol. 31, No. 5. pp. 1370-1382.
@article{5edec761ceb24e24b33ff5fed8e55d14,
title = "Minimizing the flow time without migration",
abstract = "We consider the classical problem of scheduling jobs in a multiprocessor setting in order to minimize the flow time (total time in the system). The performance of the algorithm, both in offline and online settings, can be significantly improved if we allow preemption, i.e., interrupt a job and later continue its execution, perhaps migrating it to a different machine. Preemption is inherent to make a scheduling algorithm efficient. While in the case of a single processor most operating systems can easily handle preemptions, migrating a job to a different machine results in a huge overhead. Thus, it is not commonly used in most multiprocessor operating systems. The natural question is whether migration is an inherent component for an efficient scheduling algorithm in either the online or offline setting. Leonardi and Raz [Proceedings of the Twenty-Ninth Annual ACM Symposium on Theory of Computing, El Paso, TX, 1997, pp. 110-119] showed that the well-known algorithm, shortest remaining processing time (SRPT), performs within a logarithmic factor of the optimal offline algorithm. Note that SRPT must use both preemption and migration to schedule the jobs. It is not known if better approximation factors can be reached and thus SRPT, although it is an online algorithm, becomes the best known algorithm in the offline setting. In fact, in the online setting, Leonardi and Raz showed that no algorithm can achieve a better bound. Without migration, no (offline or online) approximations are known. This paper introduces a new algorithm that does not use migration, works online, and is just as effective (in terms of approximation ratio) as the best known offline algorithm that uses migration.",
keywords = "Approximation, Flow time, Migration, Online, Scheduling",
author = "Baruch Awerbuch and Yossi Azar and Stefano Leonardi and Oded Regev",
year = "2002",
month = "5",
doi = "10.1137/S009753970037446X",
language = "English (US)",
volume = "31",
pages = "1370--1382",
journal = "SIAM Journal on Computing",
issn = "0097-5397",
publisher = "Society for Industrial and Applied Mathematics Publications",
number = "5",

}

TY - JOUR

T1 - Minimizing the flow time without migration

AU - Awerbuch, Baruch

AU - Azar, Yossi

AU - Leonardi, Stefano

AU - Regev, Oded

PY - 2002/5

Y1 - 2002/5

N2 - We consider the classical problem of scheduling jobs in a multiprocessor setting in order to minimize the flow time (total time in the system). The performance of the algorithm, both in offline and online settings, can be significantly improved if we allow preemption, i.e., interrupt a job and later continue its execution, perhaps migrating it to a different machine. Preemption is inherent to make a scheduling algorithm efficient. While in the case of a single processor most operating systems can easily handle preemptions, migrating a job to a different machine results in a huge overhead. Thus, it is not commonly used in most multiprocessor operating systems. The natural question is whether migration is an inherent component for an efficient scheduling algorithm in either the online or offline setting. Leonardi and Raz [Proceedings of the Twenty-Ninth Annual ACM Symposium on Theory of Computing, El Paso, TX, 1997, pp. 110-119] showed that the well-known algorithm, shortest remaining processing time (SRPT), performs within a logarithmic factor of the optimal offline algorithm. Note that SRPT must use both preemption and migration to schedule the jobs. It is not known if better approximation factors can be reached and thus SRPT, although it is an online algorithm, becomes the best known algorithm in the offline setting. In fact, in the online setting, Leonardi and Raz showed that no algorithm can achieve a better bound. Without migration, no (offline or online) approximations are known. This paper introduces a new algorithm that does not use migration, works online, and is just as effective (in terms of approximation ratio) as the best known offline algorithm that uses migration.

AB - We consider the classical problem of scheduling jobs in a multiprocessor setting in order to minimize the flow time (total time in the system). The performance of the algorithm, both in offline and online settings, can be significantly improved if we allow preemption, i.e., interrupt a job and later continue its execution, perhaps migrating it to a different machine. Preemption is inherent to make a scheduling algorithm efficient. While in the case of a single processor most operating systems can easily handle preemptions, migrating a job to a different machine results in a huge overhead. Thus, it is not commonly used in most multiprocessor operating systems. The natural question is whether migration is an inherent component for an efficient scheduling algorithm in either the online or offline setting. Leonardi and Raz [Proceedings of the Twenty-Ninth Annual ACM Symposium on Theory of Computing, El Paso, TX, 1997, pp. 110-119] showed that the well-known algorithm, shortest remaining processing time (SRPT), performs within a logarithmic factor of the optimal offline algorithm. Note that SRPT must use both preemption and migration to schedule the jobs. It is not known if better approximation factors can be reached and thus SRPT, although it is an online algorithm, becomes the best known algorithm in the offline setting. In fact, in the online setting, Leonardi and Raz showed that no algorithm can achieve a better bound. Without migration, no (offline or online) approximations are known. This paper introduces a new algorithm that does not use migration, works online, and is just as effective (in terms of approximation ratio) as the best known offline algorithm that uses migration.

KW - Approximation

KW - Flow time

KW - Migration

KW - Online

KW - Scheduling

UR - http://www.scopus.com/inward/record.url?scp=0036588836&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036588836&partnerID=8YFLogxK

U2 - 10.1137/S009753970037446X

DO - 10.1137/S009753970037446X

M3 - Article

AN - SCOPUS:0036588836

VL - 31

SP - 1370

EP - 1382

JO - SIAM Journal on Computing

JF - SIAM Journal on Computing

SN - 0097-5397

IS - 5

ER -