Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing最新文献_第6页

Improved Distributed Expander Decomposition and Nearly Optimal Triangle Enumeration 改进的分布扩展器分解和近最优三角枚举

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-04-17 DOI: 10.1145/3293611.3331618

Yi-Jun Chang, Thatchaphol Saranurak

{"title":"Improved Distributed Expander Decomposition and Nearly Optimal Triangle Enumeration","authors":"Yi-Jun Chang, Thatchaphol Saranurak","doi":"10.1145/3293611.3331618","DOIUrl":"https://doi.org/10.1145/3293611.3331618","url":null,"abstract":"An(ε,φ)-expander decomposition of a graph G=(V,E) is a clustering of the vertices V=V1∪…∪ Vx such that (1) each cluster Vi induces subgraph with conductance at least φ, and (2) the number of inter-cluster edges is at most ε|E|. In this paper, we give an improved distributed expander decomposition, and obtain a nearly optimal distributed triangle enumeration algorithm in the CONGEST model. Specifically, we construct an (ε,φ)-expander decomposition with φ=(ε/log n)2 O(k) in O(n2/k ⋅ poly (1/φ, log n))rounds for any ε ∈(0,1) and positive integer k. For example, a (1/no(1), 1/no(1))-expander decomposition only requires O(no(1)) rounds to compute, which is optimal up to subpolynomial factors, and a (0.01,1/poly log n)-expander decomposition can be computed in O(nγ) rounds, for any arbitrarily small constant γ > 0. Previously, the algorithm by Chang, Pettie, and Zhang can construct a (1/6,1/poly log n)-expander decomposition using Õ (n1-δ) rounds for any δ > 0, with a caveat that the algorithm is allowed to throw away a set of edges into an extra part which form a subgraph with arboricity at most nδ. Our algorithm does not have this caveat. By slightly modifying the distributed algorithm for routing on expanders by Ghaffari, Kuhn and Su [PODC'17], we obtain a triangle enumeration algorithm using Õ(n1/3) rounds. This matches the lower bound by Izumi and LeGall [PODC'17] and Pandurangan, Robinson and Scquizzato [SPAA'18] of Ø(n1/3) which holds even in the CONGESTED-CLIQUE model. To the best of our knowledge, this provides the first non-trivial example for a distributed problem that has essentially the same complexity (up to a polylogarithmic factor) in both CONGEST and CONGESTED-CLIQUE. The key technique in our proof is the first distributed approximation algorithm for finding a low conductance cut that is as balanced as possible. Previous distributed sparse cut algorithms do not have this nearly most balanced guarantee.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"37 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115942477","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}

引用次数: 39

A Recoverable Mutex Algorithm with Sub-logarithmic RMR on Both CC and DSM 在CC和DSM上具有亚对数RMR的可恢复互斥锁算法

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-04-03 DOI: 10.1145/3293611.3331634

P. Jayanti, S. Jayanti, Anup Joshi

{"title":"A Recoverable Mutex Algorithm with Sub-logarithmic RMR on Both CC and DSM","authors":"P. Jayanti, S. Jayanti, Anup Joshi","doi":"10.1145/3293611.3331634","DOIUrl":"https://doi.org/10.1145/3293611.3331634","url":null,"abstract":"In light of recent advances in non-volatile main memory technology, Golab and Ramaraju reformulated the traditional mutex problem into the novel Recoverable Mutual Exclusion (RME) problem. In the best known solution for RME, due to Golab and Hendler from PODC 2017, a process incurs at most O(√ log n log log n) remote memory references (RMRs) per passage on a system with n processes, where a passage is an interval from when a process enters the Try section to when it subsequently returns to Remainder. Their algorithm, however, guarantees this bound only for cache-coherent (CC) multiprocessors, leaving open the question of whether a similar bound is possible for distributed shared memory (DSM) multiprocessors. We answer this question affirmatively by designing an algorithm for a system with n processes, such that, it satisfies the same complexity bound as Golab and Hendler's for both CC and DSM multiprocessors. Our algorithm has some additional advantages over Golab and Hendler's: (i) its Exit section is wait-free, (ii) it uses only the Fetch-and-Store instruction, and (iii) on a CC machine our algorithm needs each process to have a cache of only O(1) words, while their algorithm needs a cache of size that is a function of n.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124527193","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}

引用次数: 20

Exact Byzantine Consensus on Undirected Graphs under Local Broadcast Model 局部广播模型下无向图的精确拜占庭一致性

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-03-27 DOI: 10.1145/3293611.3331619

M. S. Khan, Syed Shalan Naqvi, N. Vaidya

{"title":"Exact Byzantine Consensus on Undirected Graphs under Local Broadcast Model","authors":"M. S. Khan, Syed Shalan Naqvi, N. Vaidya","doi":"10.1145/3293611.3331619","DOIUrl":"https://doi.org/10.1145/3293611.3331619","url":null,"abstract":"This paper considers the Byzantine consensus problem for nodes with binary inputs. The nodes are interconnected by a network represented as an undirected graph, and the system is assumed to be synchronous. Under the classical point-to-point communication model, it is well-known that the following two conditions are both necessary and sufficient to achieve Byzantine consensus among n nodes in the presence of up to ƒ Byzantine faulty nodes: n & 3 #8805; 3 ≥ ƒ+ 1 and vertex connectivity at least 2 ƒ + 1. In the classical point-to-point communication model, it is possible for a faulty node to equivocate, i.e., transmit conflicting information to different neighbors. Such equivocation is possible because messages sent by a node to one of its neighbors are not overheard by other neighbors. This paper considers the local broadcast model. In contrast to the point-to-point communication model, in the local broadcast model, messages sent by a node are received identically by all of its neighbors. Thus, under the local broadcast model, attempts by a node to send conflicting information can be detected by its neighbors. Under this model, we show that the following two conditions are both necessary and sufficient for Byzantine consensus: vertex connectivity at least ⌋ 3 fƒ / 2 ⌊ + 1 and minimum node degree at least 2 ƒ. Observe that the local broadcast model results in a lower requirement for connectivity and the number of nodes n, as compared to the point-to-point communication model. We extend the above results to a hybrid model that allows some of the Byzantine faulty nodes to equivocate. The hybrid model bridges the gap between the point-to-point and local broadcast models, and helps to precisely characterize the trade-off between equivocation and network requirements.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115447741","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}

引用次数: 22

Near-Additive Spanners In Low Polynomial Deterministic CONGEST Time 低多项式确定性拥塞时间下的近加性扳手

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-03-03 DOI: 10.1145/3293611.3331635

Michael Elkin, Shaked Matar

{"title":"Near-Additive Spanners In Low Polynomial Deterministic CONGEST Time","authors":"Michael Elkin, Shaked Matar","doi":"10.1145/3293611.3331635","DOIUrl":"https://doi.org/10.1145/3293611.3331635","url":null,"abstract":"Given a pair of parameters α ≥ 1,β ≥ 0, a subgraph G'=(V,H) of an n-vertex unweighted undirected graph G=(V,E) is called an (α,β)-spanner if for every pair u,ν ∈ V of vertices, we have dG' (u,ν)≤ α dG (u,α)+β. If β=0 the spanner is called a multiplicative α-spanner, and if α = 1+ε, for an arbitrarily small ε>0, the spanner is said to be near-additive. Graph spanners [5,36], are a fundamental and extremely well-studied combinatorial construct, with a multitude of applications in distributed computing and in other areas. Near-additive spanners, introduced in [27], preserve large distances much more faithfully than the more traditional multiplicative spanners. Also, recent lower bounds [1] ruled out the existence of arbitrarily sparse purely additive spanners (i.e., spanners with α=1), and therefore showed that essentially near-additive spanners provide the best approximation of distances that one can hope for. Numerous distributed algorithms, for constructing sparse near-additive spanners, were devised in [17,20,25,28,40]. In particular, there are now known efficient randomized algorithms in the CONGEST model that construct such spanners [25]., and also there are efficient deterministic algorithms in the LOCAL model [17]. However, the only known deterministic CONGEST-model algorithm for the problem [20] requires super-linear time in n. In this paper, we remedy the situation and devise an efficient deterministic CONGEST-model algorithm for constructing arbitrarily sparse near-additive spanners. The running time of our algorithm is low polynomial, i.e., roughly O(β ⋅ nρ), where ρ > 0 is an arbitrarily small positive constant that affects the additive term β. In general, the parameters of our new algorithm and of the resulting spanner are at the same ballpark as the respective parameters of the state-of-the-art randomized algorithm due to [25].","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130775987","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}

引用次数: 21

Fast Concurrent Data Sketches 快速并发数据草图

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-02-28 DOI: 10.1145/3293611.3331567

Arik Rinberg, A. Spiegelman, Edward Bortnikov, Eshcar Hillel, I. Keidar, Hadar Serviansky

引用次数: 11

An Automatic Speedup Theorem for Distributed Problems 分布式问题的自动加速定理

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-02-26 DOI: 10.1145/3293611.3331611

S. Brandt

{"title":"An Automatic Speedup Theorem for Distributed Problems","authors":"S. Brandt","doi":"10.1145/3293611.3331611","DOIUrl":"https://doi.org/10.1145/3293611.3331611","url":null,"abstract":"Recently, Brandt et al. [STOC'16] proved a lower bound for the distributed Lovász Local Lemma, which has been conjectured to be tight for sufficiently relaxed LLL criteria by Chang and Pettie [FOCS'17]. At the heart of their result lies a speedup technique that, for graphs of girth at least 2t+2, transforms any t-round algorithm for one specific LLL problem into a (t-1)-round algorithm for the same problem. We substantially improve on this technique by showing that such a speedup exists for any locally checkable problem ¶i, with the difference that the problem ¶i_1 the inferred (t-1)-round algorithm solves is not (necessarily) the same problem as ¶i. Our speedup is automatic in the sense that there is a fixed procedure that transforms a description for ¶i into a description for ¶i_1 and reversible in the sense that any (t-1)-round algorithm for ¶i_1 can be transformed into a t-round algorithm for ¶i. In particular, for any locally checkable problem ¶i with exact deterministic time complexity T(n, Δ) łeq t on graphs with n nodes, maximum node degree Δ, and girth at least 2t+2, there is a sequence of problems ¶i_1, ¶i_2, dots with time complexities T(n, Δ)-1, T(n, Δ)-2, dots, that can be inferred from ¶i. As a first application of our generalized speedup, we solve a long-standing open problem of Naor and Stockmeyer [STOC'93]: we show that weak 2-coloring in odd-degree graphs cannot be solved in o(łog^* Δ) rounds, thereby providing a matching lower bound to their upper bound.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125730814","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}

引用次数: 43

With Great Speed Come Small Buffers: Space-Bandwidth Tradeoffs for Routing 高速度带来小缓冲:路由的空间带宽权衡

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-02-21 DOI: 10.1145/3293611.3331614

Avery Miller, B. Patt-Shamir, Will Rosenbaum

引用次数: 5

Fault Tolerant Gradient Clock Synchronization 容错梯度时钟同步

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-02-21 DOI: 10.1145/3293611.3331637

J. Bund, C. Lenzen, Will Rosenbaum

{"title":"Fault Tolerant Gradient Clock Synchronization","authors":"J. Bund, C. Lenzen, Will Rosenbaum","doi":"10.1145/3293611.3331637","DOIUrl":"https://doi.org/10.1145/3293611.3331637","url":null,"abstract":"Synchronizing clocks in distributed systems is well-understood, both in terms of fault-tolerance in fully connected systems, and the optimal achievable local skew in general fault-free networks. However, so far nothing non-trivial is known about the local skew that can be achieved in non-fully-connected topologies even under a single Byzantine fault. In this work, we show that asymptotically optimal local skew can be achieved in the presence of Byzantine faults. Our approach combines the Lynch-Welch algorithm [19] for synchronizing a clique of n nodes with up to ƒ < n/3 Byzantine faults, and the gradient clock synchronization (GCS) algorithm by Lenzen et al. [15] in order to render the latter resilient to faults. This is not possible on general graphs, so we augment an arbitrary input graph G by replacing each node with a fully connected cluster of 3 ƒ +1 copies, and execute an instance of the Lynch-Welch algorithm within each cluster. We interpret the clusters as supernodes executing the GCS algorithm on G, where each node in the cluster maintains an estimate of the logical clock of its supernode. By also fully connecting clusters corresponding to neighbors in l G, supernodes maintain estimates of neighboring clusters' logical clocks. We achieve asymptotically optimal local skew, assuming that no cluster contains more than ƒ faulty nodes. This construction yields factors of O(ƒ) and O(ƒ2) overheads in terms of nodes and edges, respectively. Since tolerating ƒ faulty neighbors trivially requires degrees larger than ƒ, these overheads are asymptotically optimal.","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127302122","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}

引用次数: 7

Hardness of Exact Distance Queries in Sparse Graphs Through Hub Labeling 集线器标记稀疏图精确距离查询的硬度

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-02-19 DOI: 10.1145/3293611.3331625

A. Kosowski, P. Uznański, L. Viennot

{"title":"Hardness of Exact Distance Queries in Sparse Graphs Through Hub Labeling","authors":"A. Kosowski, P. Uznański, L. Viennot","doi":"10.1145/3293611.3331625","DOIUrl":"https://doi.org/10.1145/3293611.3331625","url":null,"abstract":"A distance labeling scheme is an assignment of bit-labels to the vertices of an undirected, unweighted graph such that the distance between any pair of vertices can be decoded solely from their labels. An important class of distance labeling schemes is that of hub labelings, where a node ν ∈ G stores its distance to the so-called hubs Sν ⊆ V, chosen so that for any u,ν ∈ V there is w ∈ Su ∩ Sv belonging to some shortest uv path. Notice that for most existing graph classes, the best distance labelling constructions existing use at some point a hub labeling scheme at least as a key building block. Our interest lies in hub labelings of sparse graphs, i.e., those with |E(G)| = O (n), for which we show a lowerbound of n 2O (√log n) for the average size of the hubsets. Additionally, we show a hub-labeling construction for sparse graphs of average size O(√n RS (n)c) for some 0 < c < 1, where RS (n) is the so-called Ruzsa-Szemerédi function, linked to structure of induced matchings in dense graphs. This implies that further improving the lower bound on hub labeling size to n over 2(log n)o(1 would require a breakthrough in the study of lower bounds on RS (n), which have resisted substantial improvement in the last 70 years. For general distance labeling of sparse graphs, we show a lowerbound of 1 over 2Θ(√log n) SumIndex (n), where SumIndex (n) is the communication complexity of the SUM-I problem over Zn. Our results suggest that the best achievable hub-label size and distance-label size in sparse graphs may be Θ(n over 2(log n)c ) for some 0 < c < 1.,","PeriodicalId":153766,"journal":{"name":"Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing","volume":"15 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125762805","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}

引用次数: 11

Layering Data Structures over Skip Graphs for Increased NUMA Locality 跳跃图上的分层数据结构增加NUMA局部性

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing Pub Date : 2019-02-19 DOI: 10.1145/3293611.3331576

Samuel Thomas, H. Mendes

引用次数: 3