A quorum-based extended group mutual exclusion algorithm without unnecessary blocking (original) (raw)

A Token-Based Distributed Group Mutual Exclusion Algorithm with Quorums

IEEE Transactions on Parallel and Distributed Systems, 2008

The group mutual exclusion problem is a generalization of mutual exclusion problem such that a set of processes in the same group can enter critical section simultaneously. In this paper, we propose a distributed algorithm for the group mutual exclusion problem in asynchronous message passing distributed systems. Our algorithm is based on tokens, and a process that obtains a token can enter critical section. For reducing message complexity, it uses coterie as a communication structure when a process sends a request messages. Informally, coterie is a set of quorums, each of which is a subset of the process set, and any two quorums share at least one process. The message complexity of our algorithm is O(|Q|) in the worst case, where |Q| is a quorum size that the algorithm adopts. Performance of the proposed algorithm is presented by analysis and discrete event simulation. Especially, the proposed algorithm achieves high concurrency, which is a performance measure for the number of processes that can be in critical section simultaneously.

A Distributed Deadlock-Free Quorum-Based Algorithm for Mutual Exclusion

Quorum-based mutual exclusion algorithms enjoy many advantages such as low message complexity and high failure resiliency. The use of quorums is a well-known approach to achieving mutual exclusion in distributed environments. Several distributed based quorum mutual exclusion was presented. The number of messages required by these algorithms require between 3(sqrt of n) and 5(sqrt of n) , where n is the size of under- lying distributed system, and the deadlock can occur between requesting processes. In this paper, we present a quorum-based distributed mutual exclusion algorithm, free deadlock. Every group is organized as a logical ring of (sqrt of n) processes. A requesting process sends its request to its successor on the logical ring. When a process receives its own request after one round, it enters in the critical section. The algorithm requires 2 (sqrt of n -1) messages.

Using Maekawa’s Algorithm to Perform Distributed Mutual Exclusion in Quorums

Advances in Computing, 2012

In d istributedsystems,cooperatingprocessesshareboth local and re motersources. Chance isveryhighthatmultipleprocessesmakesimu ltaneous requests to the same resource. If the resourcerequires mutually exclusive access (critical section-CS), thensomeregulation isneeded to access it for ensuring synchronizedaccess of the resources thatonly one process could use the resource at a given time. Th is is the distributed mutual exclusion problem. The problem of coordinating the execution of critical sections by eachprocessissolved by providing mutually exclusive access to the CS. Mutual exclusion ensures that concurrent processes make a serialized access to shared resources.Quorum-based algorithms offer the advantage of protocol symmetry, spreading effort and responsibility uniformly across the distributed systems. In thispaper, we have proposed a permission baseddistributedmutual exclusion algorithmwhichis an improvement of Maekawa's algorithm. The number of messages required by the improvisedalgorithmis in the range 3Mto 5Mper critical section invocation whereMis the number of intersection nodes1 in the system. A reduction in number of message by restricting the communication of anynodewith the intersection nodes of the quorums, withoutany modification of the basic structure of the algorithm.

Two new quorum based algorithms for distributed mutual exclusion

Proceedings of 17th International Conference on Distributed Computing Systems

Two novel suboptimal algorithms for mutual exclusion in distributed systems are p r esented. One is based on the modi cation of Maekawa's grid based quorum scheme. The size of quorums is approximately p 2 p N where N is the number of sites in a network, as compared t o 2 p N of the original method. The method i s simple and geometrically evident. The second one is based on the idea o f d i e r ence sets in combinatorial theory. The resulting scheme is very close to optimal in terms of quorum size.

Comparative Study of Mutual Exclusion Algorithms in Distributed Systems

Mutual Exclusion is an important phenomenon in distributed systems. In this paper, we analyze and compare various mutual exclusion algorithms in distributed systems. In permission based mutual exclusion process waits for permission from other processes to enter into a critical section. In token based mutual exclusion, a special message called token is passed over the system and process holding the token can enter into the critical section. We present a comparative study of quorum based, token ring token asking and multiple token algorithms for mutual exclusion in distributed systems.

A new voting-based mutual exclusion algorithm for distributed systems

2013 Nirma University International Conference on Engineering (NUiCONE), 2013

Concurrency control for a distributed system had been always challenging and is getting even more critical with the increasing sophistication of such systems. There are efficient approaches reported in the existing literature that selects one candidate process from many for allowing it to enter its critical section (CS) on the basis of the number of votes received by the processes. A simple principle that a process that gets majority of the total number of votes is only to be allowed for CS ensures safety for such an algorithm as no two processes can earn majority of the total number of polls. However, this may lead to a live-lock situation where no single process reaches the magic number of majority votes. In this paper, a new voting-based algorithm has been proposed to select a process from all the candidates for CS. The proposed algorithm helps increasing the availability of the distributed system.

Group k-mutual exclusion for distributed systems

Proceedings of the IASTED International Conference on Parallel and Distributed Computing and Systems

In this paper, we propose an algorithm to solve the group k-mutual exclusion (Gk-ME) problem for distributed systems. The Gk-ME problem is concerned with controlling the concurrent accesses of some resource by at most k nodes with the constraint that no two distinct resources can be accessed simultaneously. The proposed algorithm utilizes a token circulation mechanism and does not require the nodes to have identifications. The delay and session switches of the proposed algorithm are Ω(n 2) and Ω(n), respectively.

Distributed Groups Mutual Exclusion Based on Dynamical Data Structures

2009

The group mutual exclusion (GME) problem is an interesting generalization of the mutual exclusion problem. Several solutions of the GME problem have been proposed for message passing distributed systems. In this paper we present a new Distributed Group Mutual Exclusion (DGME) based on Clients/Servers model, and uses a dynamic data structure. Several processes (Clients) can access simultaneously to a same opened session (Server). The algorithm ensures that, at any time, at most one session is opened, and any requested session will be opened in a finite time. The number of messages is between 0 and m, where m is the number of session in the network. In the average case, O(Log(m)) messages are necessary to open a session. The maximum concurrency is n, where n is the number of processes in the network.

A Fault Tolerant Token-Based Algorithm For Group Mutual Exclusion In Distributed Systems

2008

The group mutual exclusion (GME) problem is a variant of the mutual exclusion problem. In the present paper a token-based group mutual exclusion algorithm, capable of handling transient faults, is proposed. The algorithm uses the concept of dynamic request sets. A time out mechanism is used to detect the token loss; also, a distributed scheme is used to regenerate the token. The worst case message complexity of the algorithm is n+1. The maximum concurrency and forum switch complexity of the algorithm are n and min (n, m) respectively, where n is the number of processes and m is the number of groups. The algorithm also satisfies another desirable property called smooth admission. The scheme can also be adapted to handle the extended group mutual exclusion problem.

An improved quorum-based algorithm for extended GME problem in distributed systems

2010

The extended GME (group mutual exclusion) problem is a natural extension of the GME problem. In extended GME problem, processes are allowed to request more than one resource at a time, in order that the processes that can proceed by having access to any one of the requested resource can be allowed to do so. Manabe-Park suggested a quorum based solution for the extended GME problem. However, the worst case message complexity of the Manabe-Park algorithm is 9q, where q is the quorum size. Further, the synchronization delay of Manabe-Park algorithm is 4T, where T is the maximum message propagation delay. In the present paper, we propose a quorum based solution for the extended GME problem. The worst case message complexity of our algorithm is 7q and synchronization delay is 3T. Moreover, in the best case, the synchronization delay and message complexity come down to 2T and 3q respectively.