Iosif Salem, E. Schiller, M. Papatriantafilou, P. Tsigas
{"title":"Shared-object system equilibria: delay and throughput analysis","authors":"Iosif Salem, E. Schiller, M. Papatriantafilou, P. Tsigas","doi":"10.1145/2833312.2833325","DOIUrl":"https://doi.org/10.1145/2833312.2833325","url":null,"abstract":"We consider shared-object systems that require their threads to fulfill the system jobs by first acquiring sequentially the objects needed for the jobs and then holding on to them until the job completion. Such systems are in the core of a variety of shared-resource allocation and synchronization systems. This work opens a new perspective to study the expected job delay and throughput analytically, given the possible set of jobs that may join the system dynamically. We identify the system dependencies that cause contention among the threads as they try to acquire the job objects. We use these observations to define the shared-object system equilibria. We note that the system is in equilibrium whenever the rate in which jobs arrive at the system matches the job completion rate. These equilibria consider not only the job delay but also the job throughput, as well as the time in which each thread blocks other threads in order to complete its job. We then further study in detail the thread work cycles and, by using a graph representation of the problem, we are able to propose procedures for estimating equilibria, i.e., discovering the job delay and throughput, as well as the blocking time. To the best of our knowledge, this is a new perspective, that can provide better analytical tools for the problem, in order to estimate performance measures similar to ones that can be acquired through experimentation on working systems and simulations.","PeriodicalId":113772,"journal":{"name":"Proceedings of the 17th International Conference on Distributed Computing and Networking","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134630299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fast consensus under eventually stabilizing message adversaries","authors":"Manfred Schwarz, Kyrill Winkler, U. Schmid","doi":"10.1145/2833312.2833323","DOIUrl":"https://doi.org/10.1145/2833312.2833323","url":null,"abstract":"This paper1 is devoted to deterministic consensus in synchronous dynamic networks with unidirectional links, which are under the control of an omniscient message adversary. Motivated by unpredictable node/system initialization times and long-lasting periods of massive transient faults, we consider message adversaries that guarantee periods of less erratic message loss only eventually: We present a tight bound of 2D + 1 for the termination time of consensus under a message adversary that eventually guarantees a single vertex-stable root component with dynamic network diameter D, as well as a simple algorithm that matches this bound. It effectively halves the termination time 4D + 1 achieved by the fastest consensus algorithm known so far. We also introduce a generalized, considerably stronger variant of our message adversary, and show that our new algorithm, unlike the existing one, still works correctly under it.","PeriodicalId":113772,"journal":{"name":"Proceedings of the 17th International Conference on Distributed Computing and Networking","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126700315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stabilization and fault-tolerance in presence of unchangeable environment actions","authors":"Mohammad Roohitavaf, S. Kulkarni","doi":"10.1145/2833312.2833324","DOIUrl":"https://doi.org/10.1145/2833312.2833324","url":null,"abstract":"We focus on the problem of adding fault-tolerance to an existing concurrent protocol in the presence of unchangeable environment actions. Such unchangeable actions occur in cases where a subset of components/processes cannot be modified since they represent third-party components or are constrained by physical laws. These actions differ from faults in that they are (1) simultaneously collaborative and disruptive, (2) essential for satisfying the specification, and (3) possibly non-terminating. Hence, if these actions are modeled as faults while adding fault-tolerance, it causes existing algorithms to declare failure to add fault-tolerance. We present algorithms for adding stabilizing and fault-tolerance. Since previous approaches for adding stabilizing and fault-tolerance to (disruptive and eventually terminating) faults cannot be extended for environment actions, we develop new algorithms that are sound, complete and in P (in the state space).","PeriodicalId":113772,"journal":{"name":"Proceedings of the 17th International Conference on Distributed Computing and Networking","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115306492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bitcoin meets strong consistency","authors":"Christian Decker, J. Seidel, Roger Wattenhofer","doi":"10.1145/2833312.2833321","DOIUrl":"https://doi.org/10.1145/2833312.2833321","url":null,"abstract":"The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new system, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certification authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar systems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state with high probability. We also show how Discoin, a Bitcoin variant that decouples block creation and transaction confirmation, can be built on top of PeerCensus, enabling real-time payments. Unlike Bitcoin, once transactions in Discoin are committed, they stay committed.","PeriodicalId":113772,"journal":{"name":"Proceedings of the 17th International Conference on Distributed Computing and Networking","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129850386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Group mutual exclusion in linear time and space","authors":"Yuan He, K. Gopalakrishnan, E. Gafni","doi":"10.1145/2833312.2833316","DOIUrl":"https://doi.org/10.1145/2833312.2833316","url":null,"abstract":"We present two algorithms for the Group Mutual Exclusion (GME) Problem that satisfy the properties of Mutual Exclusion, Starvation Freedom, Bounded Exit, Concurrent Entry and First Come First Served. Both our algorithms use only simple read and write instructions, have O(N) Shared Space complexity and O(N) Remote Memory Reference (RMR) complexity in the Cache Coherency (CC) model. Our first algorithm is developed by generalizing the well-known Lamport's Bakery Algorithm for the classical mutual exclusion problem, while preserving its simplicity and elegance. However, it uses unbounded shared registers. Our second algorithm uses only bounded registers and is developed by generalizing Taubenfeld's Black and White Bakery Algorithm to solve the classical mutual exclusion problem using only bounded shared registers. We show that contrary to common perception our algorithms are the first to achieve these properties with these combination of complexities.","PeriodicalId":113772,"journal":{"name":"Proceedings of the 17th International Conference on Distributed Computing and Networking","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124387451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Bononi, A. Datta, Stéphane Devismes, Archan Misra
{"title":"Proceedings of the 17th International Conference on Distributed Computing and Networking","authors":"L. Bononi, A. Datta, Stéphane Devismes, Archan Misra","doi":"10.1145/2833312","DOIUrl":"https://doi.org/10.1145/2833312","url":null,"abstract":"","PeriodicalId":113772,"journal":{"name":"Proceedings of the 17th International Conference on Distributed Computing and Networking","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129538856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}