Dagstuhl Seminar Proceedings, Volume 10071
Dagstuhl Seminar Proceedings
DagSemProc
https://www.dagstuhl.de/dagpub/1862-4405
https://dblp.org/db/series/dagstuhl
1862-4405
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
10071
2010
https://drops.dagstuhl.de/entities/volume/DagSemProc-volume-10071
10071 Abstracts Collection – Scheduling
From 14.02. to 19.02.2010, the Dagstuhl Seminar 10071 ``Scheduling '' was held
in Schloss Dagstuhl-Leibniz Center for Informatics.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available.
Scheduling
real-time
complexity
approximation algorithms
1-12
Regular Paper
Susanne
Albers
Susanne Albers
Sanjoy K.
Baruah
Sanjoy K. Baruah
Rolf H.
Möhring
Rolf H. Möhring
Kirk
Pruhs
Kirk Pruhs
10.4230/DagSemProc.10071.1
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10071 Executive Summary – Scheduling
The primary objectives of this seminar were to bring together leading
researchers working on scheduling problems in three different research
communities – operations research, theoretical computer science, and
real-time systems – to expose each community to the important problems
addressed by the other communities; to enable and encourage cooperation
among the researchers; and to facilitate a transfer of solution techniques
from each community to the others.
Scheduling
real-time
complexity
approximation algorithms
1-2
Regular Paper
Susanne
Albers
Susanne Albers
Sanjoy K.
Baruah
Sanjoy K. Baruah
Rolf H.
Möhring
Rolf H. Möhring
Kirk
Pruhs
Kirk Pruhs
10.4230/DagSemProc.10071.2
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10071 Open Problems – Scheduling
Collection of the open problems presented at the scheduling seminar.
Open problems
scheduling
1-24
Regular Paper
Jim
Anderson
Jim Anderson
Björn
Andersson
Björn Andersson
Yossi
Azar
Yossi Azar
Nikhil
Bansal
Nikhil Bansal
Enrico
Bini
Enrico Bini
Marek
Chrobak
Marek Chrobak
José
Correa
José Correa
Liliana
Cucu-Grosjean
Liliana Cucu-Grosjean
Rob
Davis
Rob Davis
Arvind
Easwaran
Arvind Easwaran
Jeff
Edmonds
Jeff Edmonds
Shelby
Funk
Shelby Funk
Sathish
Gopalakrishnan
Sathish Gopalakrishnan
Han
Hoogeveen
Han Hoogeveen
Claire
Mathieu
Claire Mathieu
Nicole
Megow
Nicole Megow
Seffi
Naor
Seffi Naor
Kirk
Pruhs
Kirk Pruhs
Maurice
Queyranne
Maurice Queyranne
Adi
Rosén
Adi Rosén
Nicolas
Schabanel
Nicolas Schabanel
Jiří
Sgall
Jiří Sgall
René
Sitters
René Sitters
Sebastian
Stiller
Sebastian Stiller
Marc
Uetz
Marc Uetz
Tjark
Vredeveld
Tjark Vredeveld
Gerhard J.
Woeginger
Gerhard J. Woeginger
10.4230/DagSemProc.10071.3
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A Stochastic Framework for Multiprocessor Soft Real-Time Scheduling
Prior work has shown that the global earliest-deadline-first
(GEDF) scheduling algorithm ensures bounded deadline tardiness
on multiprocessors with no utilization loss; therefore,
GEDF may be a good candidate scheduling algorithm for
soft real-time workloads. However, such workloads are often
implemented assuming an average-case provisioning, and in
prior tardiness-bound derivations for GEDF, worst-case execution
costs are assumed. As worst-case costs can be orders
of magnitude higher than average-case costs, using a worst-case
provisioning may result in significant wasted processing
capacity. In this paper, prior tardiness-bound derivations for
GEDF are generalized so that execution times are probabilistic,
and a bound on expected (mean) tardiness is derived. It is
shown that, as long as the total expected utilization is strictly
less than the number of available processors, the expected
tardiness of every task is bounded under GEDF. The result
also implies that any quantile of the tardiness distribution is
also bounded.
The uploaded paper is from the upcoming RTAS. I would like
to hear suggestions about how to ease the assumption of
independent execution times in this analysis.
GEDF
multiprocessor
tardiness
1-10
Regular Paper
James
Anderson
James Anderson
Alex
Mills
Alex Mills
10.4230/DagSemProc.10071.4
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Energy Efficient Scheduling via Partial Shutdown
We define a collection of new problems referred to as ``machine activation''
problems. The central framework we introduce considers a collection of M
machines (unrelated or related), with machine $i$ having an activation
cost of $a_i$.
There is also a collection of N jobs that need to be performed, and
$p_{ij}$ is the processing time of job $j$ on machine $i$.
Standard scheduling models assume that the set of machines is fixed
and all machines are available. We assume that there is an activation cost
budget of $A$
-- we would like to select a subset S of the machines to activate
with total cost $a(S)le A$ and find a schedule for the jobs on the
machines in $S$ minimizing the makespan. In this work we develop
bi-criteria approximation algorithms for this problem based on both
LP rounding and a greedy approach.
Unrelated parallel machine scheduling
approximation algorithms
1-0
Regular Paper
Samir
Khuller
Samir Khuller
Jian
Li
Jian Li
Barna
Saha
Barna Saha
10.4230/DagSemProc.10071.5
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Every Deterministic Nonclairvoyant Scheduler has a Suboptimal Load Threshold
The goal is to prove a surprising lower bound for resource augmented nonclairvoyant algorithms for scheduling jobs with sublinear nondecreasing speed-up curves on multiple processors with the objective of average response time. Edmonds and Pruhs in SODA09 prove that for every $\e > 0$, there is an algorithm $\alg_{\e}$ that is $(1\!+\!\epsilon)$-speed $O({1 \over
\e2})$-competitive. A problem, however, is that this algorithm
$\alg_{\e}$ depends on $\e$. The goal is to prove that every fixed
deterministic nonclairvoyant algorithm has a suboptimal speed
threshold, namely for every (graceful) algorithm $\alg$, there is a
threshold $1\!+\!\beta_{\alg}$ that is $\beta_{\alg} > 0$ away from
being optimal such that the algorithm is $\Omega({1 \over \e
\beta_{\alg}})$ competitive with speed $(1 \!+\! \beta_{\alg}) \!+\!
\e$ and is $\omega(1)$ competitive with speed $1 \!+\! \beta_{\alg}$.
I have worked very hard on it and have felt that I was close. The
proof technique is to use Brouwer's fixed point theorem to break the
cycle of needing to know which input will be given before one can know
what the algorithm will do and needing to know what the algorithm will
do before one can know which input to give. Every thing I have can be
found at
Scheduling
1-0
Regular Paper
Jeff
Edmonds
Jeff Edmonds
10.4230/DagSemProc.10071.6
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Optimal Mechanisms for Scheduling
We study the design of optimal mechanisms in a setting where a service provider needs to schedule a set of non-preemptive jobs, one job at a time. Jobs need to be compensated for waiting, and waiting cost is private information. In this setting, an optimal mechanism is one that induces jobs to report truthfully their waiting cost, while minimizing the total expected compensation cost of the service provider. Here, truthful refers to Bayes-Nash implementability,
and assumes that private information is independently drawn from known distributions. We derive closed formulae for the optimal mechanism, and show that it is a modification of Smith’s ratio rule. We also show that it can be implemented in dominant strategies. Our analysis relies on a graph-theoretic interpretation of the incentive compatibility constraints. It parallels the
analysis known for auctions with single parameter agents, yet it exhibits some subtle differences.
We also consider the multi-dimensional case where also the service times of jobs are private information. We show that for this problem the optimal mechanism generally does not satisfy an independence condition known as IIA, and thus known approaches are doomed to fail.
Optimal Mechanism Design
Scheduling
Job Agents
Smith's Rule
1-22
Regular Paper
Birgit
Heydenreich
Birgit Heydenreich
Debasis
Mishra
Debasis Mishra
Rudolf
Müller
Rudolf Müller
Marc
Uetz
Marc Uetz
10.4230/DagSemProc.10071.7
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Polynomial Time Algorithms for Minimum Energy Scheduling
The aim of power management policies is to reduce the amount of energy consumed by computer systems while maintaining satisfactory level of performance. One common method for saving energy is to simply suspend the system during the idle times. No energy is consumed in the suspend mode. However, the process of waking up the system itself requires a certain fixed amount of energy, and thus suspending the system is beneficial only if the idle time is long enough to compensate for this additional energy expenditure. In the specific problem studied in the paper, we have a set of jobs with release times and deadlines that need to be executed on a single processor. Preemptions are allowed. The processor requires energy L to be woken up and, when it is on, it uses the energy at a rate of R units per unit of time. It has been an open problem whether a schedule minimizing the overall energy consumption can be computed in polynomial time. We solve this problem in positive, by providing an O(n5)-time
algorithm. In addition we provide an O(n4)-time algorithm for computing the minimum energy schedule when all jobs have unit length.
Scheduling
algorithm
dynamic programming
energy
1-12
Regular Paper
Marek
Chrobak
Marek Chrobak
Philippe
Baptiste
Philippe Baptiste
Christoph
Dürr
Christoph Dürr
10.4230/DagSemProc.10071.8
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Power-Aware Real-Time Scheduling: Models, Open Problems, and Practical Considerations
Power-related issues have received considerable research attention from the real-time community in the past decade. In our talk, we introduce a recent model and set of assumptions made in the recent real-time literature on energy and thermal issues; suggest two high-level open problems for power-aware real-time scheduling: {em peak-temperature minimization} and {em energy-minimization with temperature as a constraint}; and discuss practical considerations that should be considered in proposed solutions.
Real-time scheduling
power-aware scheduling
sporadic tasks
1-4
Regular Paper
Nathan
Fisher
Nathan Fisher
10.4230/DagSemProc.10071.9
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Recent Hardness Results for Periodic Uni-processor Scheduling
Consider a set of $n$ periodic tasks $ au_1,ldots, au_n$ where $ au_i$ is described
by an execution time $c_i$, a (relative) deadline $d_i$ and a period $p_i$.
We assume that jobs are released synchronously (i.e. at each multiple of $p_i$) and consider pre-emptive, uni-processor schedules.
We show that computing the response time of a task $ au_n$ in a Rate-monotonic schedule
i.e. computing
[
minleft{ r geq mid c_n + sum_{i=1}^{n-1} leftlceil frac{r}{p_i}
ight
ceil c_i leq r
ight}
]
is (weakly) $mathbf{NP}$-hard (where $ au_n$ has the lowest priority and the deadlines
are implicit, i.e. $d_i = p_i$).
Furthermore we obtain that verifying EDF-schedulability, i.e.
[
forall Q geq 0: sum_{i=1}^n left( leftlfloor frac{Q-d_i}{p_i}
ight
floor +1
ight)cdot c_i leq Q
]
for constrained-deadline tasks ($d_i leq p_i$) is weakly $mathbf{coNP}$-hard.
Hardness
periodic scheduling
uni-processor scheduling
1-7
Regular Paper
Friedrich
Eisenbrand
Friedrich Eisenbrand
Thomas
Rothvoss
Thomas Rothvoss
10.4230/DagSemProc.10071.10
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Resource Sharing in Global Fixed-Priority Preemptive Multiprocessor Scheduling
In this paper we consider global fixed-priority preemptive multiprocessor scheduling of constrained-deadline sporadic tasks that share resources in a non-nested manner. We develop a novel resource-sharing protocol and a corresponding schedulability test for this system. We also develop the first schedulability analysis of priority inheritence protocol for the aforementioned system. Finally, we show that these protocols are efficient (based on the developed schedulability tests) for a class of priority-assignments called emph{reasonable} priority-assignments.
Scheduling
1-0
Regular Paper
Arvind
Easwaran
Arvind Easwaran
Björn
Andersson
Björn Andersson
10.4230/DagSemProc.10071.11
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Scalably Scheduling Processes with Arbitrary Speedup Curves
We give a scalable ((1+\epsilon)-speed O(1)-competitive) nonclairvoyant algorithm for scheduling jobs with sublinear nondecreasing speed-up curves on multiple processors with the objective of average response time.
Scheduling
1-9
Regular Paper
Jeff
Edmonds
Jeff Edmonds
Kirk
Pruhs
Kirk Pruhs
10.4230/DagSemProc.10071.12
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Scheduling periodic tasks in a hard real-time environment
We consider a real-time scheduling problem that occurs in the design
of software-based aircraft control. The goal is to distribute tasks
$ au_i=(c_i,p_i)$ on a minimum number of identical machines and to
compute offsets $a_i$ for the tasks such that no collision occurs. A
task $ au_i$ releases a job of running time $c_i$ at each time $a_i +
kcdot p_i, , k in mathbb{N}_0$ and a collision occurs if two jobs are
simultaneously active on the same machine.
We shed some light on the complexity and approximability landscape of this problem.
Although the problem cannot be approximated
within a factor of $n^{1-varepsilon}$ for any $varepsilon>0$, an interesting restriction
is much more tractable: If the periods are dividing (for each $i,j$ one has $p_i |
p_j$ or $p_j | p_i$), the problem allows for a better structured representation of solutions, which leads
to a 2-approximation. This result is tight, even asymptotically.
Real-Time Scheduling
Periodic scheduling problem
Periodic maintenance problem
Approximation hardness
Approximation algorithm
1-3
Regular Paper
Friedrich
Eisenbrand
Friedrich Eisenbrand
Nicolai
Hähnle
Nicolai Hähnle
Martin
Niemeier
Martin Niemeier
Martin
Skutella
Martin Skutella
Jose
Verschae
Jose Verschae
Andreas
Wiese
Andreas Wiese
10.4230/DagSemProc.10071.13
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The Parallel Supply Function Abstraction for a Virtual Multiprocessor
A new abstraction --- the Parallel Supply Function (PSF) --- is
proposed for representing the computing capabilities offered by
virtual platforms implemented atop identical multiprocessors. It is
shown that this abstraction is strictly more powerful than
previously-proposed ones, from the perspective of more accurately
representing the inherent parallelism of the provided computing
capabilities. Sufficient tests are derived for determining whether
a given real-time task system, represented as a collection of
sporadic tasks, is guaranteed
to always meet all
deadlines when scheduled upon a specified virtual platform using the
global EDF scheduling algorithm.
Virtual multiprocessor
1-14
Regular Paper
Enrico
Bini
Enrico Bini
Bertogna
Marko
Bertogna Marko
Sanjoy K.
Baruah
Sanjoy K. Baruah
10.4230/DagSemProc.10071.14
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