A STRATEGYPROOF AUCTION MECHANISM FOR GRID
SCHEDULING WITH SELFISH ENTITIES
V. Hastagiri Prakash
Indian Institute of Science
Bangalore - 560012, India
Y. Narahari
Indian Institute of Science
Bangalore - 560012, India
Keywords:
Grid computing, Grid scheduling, Resource management, procurement auctions, parallel flow, selfishness,
rationality, incentives, VCG Mechanisms.
Abstract:
With major advances in computing technology and network performance, grid computing is strategically
placed to become the future of enterprise and even personal computing. One of the most important issues
concerned with grid computing is that of application scheduling. The type of scheduling algorithm used will
depend on the type of the application. In a global grid setting, the individual users must be provided with an
incentive to offer their resources. The situation becomes non-trivial because of the fact that these entities are
intelligent, rational and selfish resource providers who, for strategic reasons, may not provide truthful infor-
mation about their processing power and cost structure. In this scenario, apart from optimality of the algorithm
used, strategy-proofness of the underlying mechanism becomes important. This paper presents a strategyproof
mechanism based scheduling algorithm for parallel flow type applications in the form of a reverse auction.
1 INTRODUCTION
Started as a new computing infrastructure, grid com-
puting is now becoming a mainstream technology for
large scale resource sharing and system integration.
With the power and presence of the grid computing
systems poised to increase with time, fast, efficient
and truthful mechanisms are needed to exploit the
power of the grid to the fullest. For a detailed in-
troduction to grid computing, see (Foster and Kessel-
man, 2002). Various design and operational issues ex-
ist in this paradigm of computing, chief among them
being scheduling and resource management. For a de-
tailed survey on grid scheduling systems and issues,
the reader is referred to (Zhu, 2003). Due to the dis-
tibuted, heterogeneous and selfish nature of the partic-
ipating entities, market based models have long been
advocated as a panacea to the issue of grid schedul-
ing, examples of which are (Buyya, 2002), (Wolski
et al., 2002). The participating resource providers and
consumers, being selfish, rational and intelligent, will
attempt at tampering with the existing mechanisms as
much as the rules allow them in order to optimize their
profit or execution time. This scenario, though possi-
bly profitable for the individuals, tends to bring down
the overall efficiency of the grid system as a whole. In
order to address this issue, we need to develop robust
mechanisms which ensure efficiency in the presence
of selfish and rational agents.
1.1 Motivation
Consider an enterprise with a number of branches
spread geographically. Now the central administra-
tion needs to use a grid system to process data, col-
lected from each of these branches, by a fixed dead-
line. Though there might be dependencies between
the sub-jobs from a single branch, there lie no depen-
dencies between jobs from different branches. So, the
central authority can schedule these equal jobs inde-
pendently. The authority would like to schedule the
jobs on different sites on the grid for quick execu-
tion. But, when the job is actually given out, the
sites may not disclose the true details of their spec-
ifications thereby leading to a sub optimal allocation
both in terms of cost and time.
In the grid scenario, we often have jobs which can be
split into a number of sub-jobs each of them being
almost equivalent in terms of their resource require-
ment and the expected time of completion. This slight
variation from the parameter sweep type scheduling
gives the problem a new structure and helps us model
178
Hastagiri Prakash V. and Narahari Y. (2006).
A STRATEGYPROOF AUCTION MECHANISM FOR GRID SCHEDULING WITH SELFISH ENTITIES.
In Proceedings of WEBIST 2006 - Second International Conference on Web Information Systems and Technologies - Internet Technology / Web
Interface and Applications, pages 178-183
DOI: 10.5220/0001255301780183
Copyright
c
SciTePress
it uniquely. To the best of our knowledge, this type of
application specific economic scheduling mechanism
is not proposed anywhere in literature. The setting
and solution for the problem inherently invokes game
theoretic modeling with auctions as our choice of im-
plementation.
1.2 The Problem
In this paper, we develop a scheduling algorithm
and payment mechanism for the type of application
scheduling problem discussed above. We set up the
problem in the form of a reverse auction. If we were
to have truthful information about the capabilities and
costs of the resource providers, the scheduling prob-
lem can be cast as an optimization problem. We pro-
vide an efficient scheduling algorithm along with a
payment structure that ensures truthful elicitation of
valuations from the bidders. The grid user whose job
is to be scheduled has a deadline which is known only
to him. He then proceeds to conduct an auction invit-
ing bids for single units of the job. The bids represent
the valuations of the resource providers for a unit of
the job when working at a given percentage of their
capacity. In development of the scheduling algorithm,
we assume that we have obtained truthful values for
the valuations which is in turn ensured by the payment
mechanism we propose.
1.3 Related Work
Market based mechanisms for distributed computing
had been initially suggested in (Hogg et al., 1992)
when they applied market principles to scheduling in
a distributed system.Though the research precedes
the popular advent of grid computing, Spawn was the
first implementation of a distributed computational
economy that acted as a precursor to many of the
market based models that were developed later.
One very important work in this area was the
dissertation work of Buyya (Buyya, 2002). In
this work he identified the key requirements of
an economic-based Grid system and developed a
distributed computational economy framework called
the Grid Architecture for Computational Economy
(GRACE), which is generic enough to accom-
modate different economic models and maps well
onto the architecture of wide area distributed systems.
Nisan et al (Nisan et al., 1998) suggested an eco-
nomic model for grids called POPCORN for trading
online CPU time among distributed computers. In
their system a virtual currency called ”popcoin” was
used as the unit of trade between buyers and sellers.
The market was an auction based one and the social
efficiency and price stability were studied using the
Vickrey auction theory.
Some general classes of scheduling problems along
with auction protocols for the same were studied
in (Wellman et al., 1998). Decentralized economic
protocols were suggested for scheduling. They had
also compared direct revelation mechanisms to the
market based methods.
Various game theoretic models, mechanisms and
auction models were applied in grid scheduling
issues in Grosu et al (Grosu et al., 2002), (Grosu
and Chronopoulos, 2003), (Grosu and Chronopoulos,
2004), (Das and Grosu, 2005). These works dealt
with mechanisms and models to cope with selfishness
of the grid users and designed strategy-proof mecha-
nisms and auction algorithms for generic scheduling
on the grid.
Most of the work discussed dealt with distributed
scheduling using a game theoretic approach or mar-
ket based models. They did not look at specific prob-
lems arising in grid computing. Grid computing with
its characteristic flow models and implementation is-
sues is completely different from a conventional dis-
tributed system. Works propounding actual schedul-
ing algorithms for the grid fail to take into account
the selfish nature of the entities involved. It is this
research gap that this paper attemps at addressing.
1.4 Our Contributions
The primary focus of this work is to ensure schedul-
ing efficiency in the presence of rational and self-
interested users and resource providers. We initially
design the auction for the scheduling problem. As-
suming that the bids received were truthful, we then
formulate the auction assignment as an optimization
problem. The specific structure of the problem allows
us to develop an algorithm for effiecient deadline-
based scheduling for parallel-flow type applications.
In order to counter the degradation of efficiency due to
actions of selfish agents, we propose a payment mech-
anism based on the famed Groves’ Mechanism from
the Vickrey-Clarkes-Groves(VCG) stable. As a result
of this application of VCG mechanism, the payment
mechanism induces the bidders to bid their true valu-
ations thereby enabling the algorithm to calculate the
optimal allocation.
1.5 Organization of the Paper
The paper is organized as follows: We give a very
brief introduction to auctions and mechanism design
in Section 2. We explain the model and formulate the
A STRATEGYPROOF AUCTION MECHANISM FOR GRID SCHEDULING WITH SELFISH ENTITIES
179
problem in Section 3. Assumptions and limitations
with respect to the model chosen are also presented in
this section. In section 4, we develop the optimal al-
location algorithm followed by the design of the pay-
ment mechanism. Finally, in section 5, we present our
conclusions and scope for future research.
2 A PRIMER ON MECHANISM
DESIGN
In this section, we give a brief introduction to the con-
cepts of mechanism design with focus on VCG mech-
anisms. Most of the material in this section is adapted
from (Narahari and Dayama, 2005).
Consider a set of agents (grid users or service
providers) N =1, 2, ..., n with agent i having a type
set Θ
i
. The type set of an agent represents the set
of perceived values of an agent. In the case of grid
computing, the type set of an agent refers to the cost
structure and deadline information of the users. Let
Θ be the cartesian product of all the type sets of all
the agents. Let X be the set of all outcomes. In our
sense, an outcome refers to a possible allocation of
jobs to providers and the associated payment made to
them. A social choice function is a mapping from Θ
to X which associates an outcome for every type pro-
file. With respect to grid scheduling, the social choice
function corresponds to an efficient way of allocating
jobs to service providers. Let S
i
denote the action set
of agent i, that is S
i
is the set of all actions available
to the agent in a given situation. A given strategy s
i
is a mapping from Θ
i
S
i
. In a Grid setting, the
strategy of the resource providers is the information
they release about their cost structure. Suppose S is
the cartesian product of all the strategy sets. A mech-
anism is then a tuple (S
1
,S
2
, ..., S
n
,g(.)), where g is
the mapping from S to X. That is, g(.) maps every
strategy profile into an outcome. A game with incom-
plete information can be associated with every mech-
anism. This game is called the game induced by the
mechanism.
We say that a mechanism µ =(S
1
,S
2
, ..., S
n
,g(.))
implements a social choice function f if there is an
equilibrium strategy profile (s
1
(.),s
2
(.), ..., s
n
(.)) of
the game induced by µ such that
g(s
1
(θ
1
),s
2
(θ
2
), ..., s
n
(θ
n
)) = f (θ
1
2
, ..., θ
n
)
for all possible type profiles (θ
1
2
, ..., θ
n
). That
is, a mechanism implements a social choice function
f(.) if there is an equililibrium of the game induced
by the mechanism that yields the same outcomes as
f(.) for each possible profile of types. Based on
the type of equilibrium, two common types of imple-
mentations are dominant strategy implementation and
bayesian Nash implementation. For a more detailed
view of these concepts the reader is reffered to (Mas-
Colell et al., 1995).
We now give some of the desirable properties of a
mechanism:
Efficiency A general criterion for evaluating a mech-
anism is Pareto efficiency, meaning that no agent
could improve its allocation without making at
least one other agent worse off. Another metric of
efficiency is allocative efficiency which is achieved
when the total value of all the winners is maxi-
mized.
Individual rationality A mechanism is individual ra-
tional if its allocation does not make any agent
worse-off than had the agent abstained from par-
ticipating in the mechanism.
Incentive compatibility A mechanism is incentive
compatible if the agents maximize their expected
payoffs by bidding true valuations for the goods.
It is desired that truthful bidding by agents should
lead to a well defined equilibrium such as domi-
nant strategy equilibrium or Bayesian Nash Equi-
librium.
Strategy proofness A mechanism is said to be strat-
egy proof if it is incentive compatibile and imple-
ments the desired social choice function in domi-
nant strategies. This is a very strong concept and
is a highly desirable property of a mechanism but
because of its stringent requirements, is not present
in most occasions.
2.1 Vickrey-Clarke-Groves
Mechanisms
The simplest model of this group of mechanisms is
the second price sealed bid auction (Vickrey auction)
for a single item. The Vickrey auction is shown to
be incentive compatible in dominant strategies (strat-
egy proof). Clarke mechanisms and Groves mecha-
nisms provide a broader class of incentive compatible
mechanisms. All these mechanisms are collectively
referred to as VCG (Vickrey-Clarke-Groves) mecha-
nisms. These mechanisms induce truth revelation by
providing a discount to each winning buying agent on
his actual bid. This discount which is called the Vick-
rey Discount is actually the extent by which the total
revenue to the seller is increased due to the presence
of this bidder. If the agents are selling agents, then we
have Vickrey surplus which is the additional amount
given to a selling agent over and above what he has
quoted. The VCG mechanisms are highly attractive
because of the fact that generally they are allocatively
efficient, individual rational, weakly budget balanced,
and incentive compatible. But they are limited in their
WEBIST 2006 - INTERNET TECHNOLOGY
180
application by the fact that they assume quasi-linear
utilities for the participating agents.
2.1.1 Groves Mechanism
A Groves mechanism is a direct revelation mecha-
nism M =(Θ
1
, Θ
2
, ..., Θ
n
,f(.)) in which the func-
tion f (θ)=(k
(θ),t
1
(θ), ..., t
n
(θ)) satisfies two
properties:
1. Allocative efficiency
θ Θk K,
n
i=1
v
i
(K
(θ)
i
))
n
i=1
v
i
(k, θ
i
) (1)
2. i N , the payment received by agent i is of the
form
t
i
(θ)=t
i
(θ
i
i
)=h
i
(θ
i
)+
j=i
v
j
(k
(θ)
j
) (2)
where h
i
(θ
i
) is any arbitrary function h
i
:
Θ
i
→for each i N
2.1.2 Clarke’s Mechanism
This is a special case of Groves mechanism when the
h
i
(θ
i
) function is of a particular intuitive form
h
i
(θ
i
)=
j=i
v
j
(k
i
(θ
i
)
j
) (3)
3 THE MODEL
We consider a grid user in a grid computing system
who is about to submit a job to be processed on the
grid. The nature of the job is such that it can be
parallelized into n approximately equal sub-jobs that
can be executed in parallel without any dependencies.
The user has a deadline d by which the entire job is
to be completed. The user is ready to pay for the ser-
vices of resource providers. Without loss of general-
ity, the de facto mode of payment can be considered
to be grid dollars G$ (Das and Grosu, 2005). It is
to be noted here that a single resource provider can
take up many sub-jobs. We consider a buyer-operated
marketplace where the mechanism used is a procure-
ment auction. The buyer sends out the specifications
of the jobs on the grid broadcast system without actu-
ally revealing the deadline. The buyer then proceeds
to invite bids from the resource provider for execution
of a single sub-job in the following format.
(t
i
,T
i
,C
i
,c
i
)
Figure 1: Cost Curve of a Resource Provider.
where t
i
is the minimum time required by the i’th user
to complete the sub-job at cost C
i
and T
i
is the time
beyond which the cost is constant at c
i
. Between t
i
and T
i
, the cost is assumed to be linear.
Now the problem for the buyer is to find upto n re-
source providers to whom the sub-jobs may be com-
mitted for execution. The grid user in addition to
meeting his deadline would also like to minimize his
total expenditure. Because the resource providers are
selfish and rational and are thus looking to maximize
their profit, they will not report their true cost curves.
So, the buyer, in order to find the optimal alloca-
tion, has to employ an incentive compatible payment
mechanism to elicit truthful bids from the resource
providers. As soon as the user receives the bids, he
can eliminate all bids with t
i
>dwhich removes re-
source providers whose processing power does not al-
low them to meet the deadline.
4 PROBLEM FORMULATION
AND OPTIMAL ALLOCATION
ALGORITHM
Assume that the user is left with m bids after elimi-
nation as explained in the previous section. Given the
structure of the grid and the number of users present,
we can safely assume that m>n.
Define,
λ
i
=
C
i
c
i
T
i
t
i
(4)
where λ
i
becomes the slope of the cost curve for bid-
der i.
Now the user is aware of his deadline and sets up the
allocation problem as a non-linear integer program-
ming problem as follows:
A STRATEGYPROOF AUCTION MECHANISM FOR GRID SCHEDULING WITH SELFISH ENTITIES
181
lmin
m
i=1
c
i
+max T
i
d
x
i
, 0 λ
i
x
i
(5)
s.t
m
i=1
x
i
= n
x
i
N
where x
i
is the variable which indicates number of
jobs allocated to resource provider i. Though the so-
lution of this integer programming problem is diffi-
cult, the structured nature of this problem leads to an
elegant and efficient algorithm.
4.1 Optimal Allocation Algorithm
Knowing the deadline, d, the metric r
i
is computed
by the user as follows:
r
i
=
λ
i
,T
i
>d
0,T
i
<d
(6)
Then the prices charged by each of the bidders for
execution time d are computed using the formula
p
i
= c
i
+(T
i
d)r
i
. With these prices for a single
sub-job execution, n minimum cost providers are
selected initially. Then, using an iterative search, the
optimal allocation is found among these n bidders.
It is to be noted that we have assumed truthful and
correct values of the bids in order to compute the
optimal assignment. This assumption is justified by
the payment mechanism which ensures this.
The winners determination algorithm can be summa-
rized as follows:
compute p
i
= c
i
+(T
i
d) r
i
i =1, 2, ..., m
Choose P
(1)
,P
(2)
, ..., P
(n)
from sorted
order P
(1)
,P
(2)
, ..., P
(m)
Allocate one sub-job to each of these
n providers
set last=n
loop for i=1 to last
loop for j=last to 1 and j = i
if deadline is met and cost does
not increase
increase allocation to i by 1
decrease allocation to j by 1
if j=0,remove j from list,last--
4.2 Coping with Selfishness
This algorithm produces an optimal solution to the
scheduling problem assuming that the bids received
were truthful. But this is not generally the case
when the system consists of self-interested, rational
resource providers. Now, this can be ensured by de-
vising an appropriate payment scheme which incen-
tivises the bidders to bid truthful values. On the lines
of the famed VCG mechanisms, the payment to a re-
source provider is computed by giving a surplus to
the winning bidder that is equal to the overall value
the bidder adds to the revenue of the auctioneer.
Recall that the VCG mechanisms can be applied to
scenarios in which the agents have quasi-linear utili-
ties, or utilities of the form:
u
i
(x, θ
i
)=v
i
(k, θ
i
)+(m
i
+ t
i
) (7)
where u
i
is the utility function, x is an outcome in the
game, θ
i
is the private valuation of player i, v
i
is the
cost incurred by player i in participating in this mech-
anism, k is the allocation vector, m
i
is some form of
endowment or participation fee and t
i
is the payment
received by player i.
It can be immediately seen that the model we have
proposed clearly falls in this category because the util-
ity to a resource provider is the difference between his
cost of execution of the job using his resources mi-
nus the payment he recieves for completing the job.
Hence, the VCG mechanisms can be applied directly
in this setting.
Recall from section 2, the structure of the incentive
to be given to an agent in the Clarke’s mechanism
h
i
(θ
i
)=
j=i
v
j
(k
i
(θ
i
)
j
) (8)
This simply means that the loss to the grid user,
who submits a job, due to the absence of each of the
resource providers must be given back to the resource
provider as an incentive to induce him to reveal his
true valuation. This means that this calculated value
must be given to the selected resource providers over
and above their bid for the tasks. It is very simple
to see that if a resource provider was not part of
the final allocation as determined by the winners
determination algorithm, then their incentive value is
0, while for those providers who were part of the final
allocation this is simply the difference between the
total payment made with and without that particular
node in the bidding process. This means we have
to run the winners determination algorithm k more
times (k n). Though this adds to the overall
complexity of the process, considering the truthful
values it induces, it is but a small price to pay.
WEBIST 2006 - INTERNET TECHNOLOGY
182
4.3 Complexity Analysis
The complexity determining step in the above algo-
rithm is the operations within the two loops which
takes Θ(m
2
) steps. Step 2 which involves sorting of
m elements would take only Θ(mlogm) time. Since
m>nand the other steps are linear time computable,
the entire algorithm is Θ(m
2
) time solvable. But,
the application of payment rule according to Clarke’s
mechanism demands that the algorithm be run max-
imum of n+1 times which adds a factor of m to the
overall complexity of the process thereby yielding a
Θ(m
3
) complexity.
Thus the payment mechanism ensures truthful bids
and the optimal allocation algorithm ensures an ef-
ficient and reasonably fast allocation of the sub-jobs.
5 CONCLUSION
The Algorithm developed in the paper computes
an optimal allocation of jobs to resource providers
and the payment mechanism which is inspired by
the VCG mechanism ensures truthful dissemination
of information. The Mechanism is highly robust
because of its allocative efficiency and strategy
proofness. The allocation algorithm and payment
structure works optimally within the limitations and
assumptions discussed in this paper. The optimal
algorithm presents a clever way of circumventing
the problems associated with the inherent non-linear
integer programming formulation.
We have considered one model of application
scheduling on the grid. Such strategy proof mecha-
nisms must be developed for more models if we have
to truly unleash the power of grid computing. A nec-
essary improvement would be to estimate the effi-
ciency of this mechanism by comparitive simulation
with other scheduling mechanisms. Only through ex-
tensive simulations can we conclude that this mech-
anism would work in a grid setting. Another im-
provement would be to relax the assumption that all
the sub-jobs are of equal size. One more relaxation
could be made to the linear cost model of the re-
source providers, replacing it with a piece-wise linear
model. Procurement auctions of the type involving
piece-wise linear cost models can be studied in (Eso
et al., 2001)
REFERENCES
Buyya, R. (2002). Economic-based Distributed Resource
Management and Scheduling for Grid Computing.
PhD thesis, School of Computer Science and Software
Engineering, Monash University, Australia.
Das, A. and Grosu, D. (2005). Combinatorial auction-based
protocols forresource allocation in grids. In IPDPS05.
Eso, M., Ghosh, S., Kalagnanam, J., and Ladayani, L.
(2001). Bid evaluation in procurement auctions
with piece-wise linear supply curves. Technical re-
port, IBM Research Division, Yorktown Heights, NY
10598.
Foster, I. and Kesselman, C. (2002). The Grid: Blueprint for
a new computing infrastructure. Morgan kaufmann
publishers.
Grosu, D. and Chronopoulos, A. (2003). A load balancing
mechanism with verification. In IPDPS03.
Grosu, D. and Chronopoulos, A. (2004). Algorithmic mech-
anism design for load balancing in distributed sys-
tems. In IPDPS04.
Grosu, D., Chronopoulos, A., and Leung, M. (2002). Load
balancing in distributed systems: An approach using
cooperative games. In IPDPS02.
Hogg, W. C., T., Huberman, B., J., K., and Stornetta, W.
(1992). Spawn: a distributed computational econ-
omy. IEEE transactions on software engineering,
18(2):103–117.
Mas-Colell, A., Whinston, M., and Green, J. (1995). Mi-
croeconomic Theory. Oxford University Press, New
York.
Narahari, Y. and Dayama, P. (2005). Combinatorial auc-
tions for electronic business. Sadhana, 30(2-3):179–
211.
Nisan, N., London, S., Regev, O., and Camiel, N. (1998).
The popcorn market-online markets for computational
resources. In First International conference on Infor-
mation and Computational Economies.
Wellman, M., Walsh, W., Wurman, P., and MacKie-Mason,
J. (1998). Some economics of market based distrib-
uted scheduling. In ICDCS98.
Wolski, R., Plank, J., Brevik, J., and Bryan, T. (2002). G-
commerce: Market formulations controlling resource
allocation on the computational grid. In AAMAS 2002.
Zhu, Y. (2003). A survey on grid scheduling systems. Tech-
nical report, Department of Computer Science, Hong
Kong University of Science and Technology, Hong
Kong.
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