Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures最新文献

{"title":"Session details: Session 4","authors":"H. Attiya","doi":"10.1145/3250641","DOIUrl":"https://doi.org/10.1145/3250641","url":null,"abstract":"","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128522204","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":"Optimal patrolling of fragmented boundaries","authors":"Andrew Collins, J. Czyzowicz, L. Gąsieniec, A. Kosowski, E. Kranakis, D. Krizanc, R. Martin, Oscar Morales-Ponce","doi":"10.1145/2486159.2486176","DOIUrl":"https://doi.org/10.1145/2486159.2486176","url":null,"abstract":"A set of mobile robots is deployed on a simple curve of finite length, composed of a finite set of vital segments separated by neutral segments. The robots have to patrol the vital segments by perpetually moving on the curve, without exceeding their uniform maximum speeds. The quality of patrolling is measured by the idleness, i.e., the longest time period during which any vital point on the curve is not visited by any robot. Given a configuration of vital segments, our goal is to provide algorithms describing the movement of the robots along the curve so as to minimize the idleness. Our main contribution is a proof that the optimal solution to the patrolling problem is attained either by the cyclic strategy, in which all the robots move in one direction around the curve, or by the partition strategy, in which the curve is partitioned into sections which are patrolled separately by individual robots. These two fundamental types of strategies were studied in the past in the robotics community in different theoretical and experimental settings. However, to our knowledge, this is the first theoretical analysis proving optimality in such a general scenario. Throughout the paper we assume that all robots have the same maximum speed. In fact, the claim is known to be invalid when this assumption does not hold, cf. [Czyzowicz et al., Proc. ESA 2011].","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134070390","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":"Truly parallel burrows-wheeler compression and decompression","authors":"J. Edwards, U. Vishkin","doi":"10.1145/2486159.2486164","DOIUrl":"https://doi.org/10.1145/2486159.2486164","url":null,"abstract":"We present novel work-optimal PRAM algorithms for Burrows-Wheeler (BW) compression and decompression of strings over a constant alphabet. For a string of length n, the depth of the compression algorithm is O(log2 n), and the depth of the corresponding decompression algorithm is O(log n). These appear to be the first polylogarithmic-time work-optimal parallel algorithms for any standard lossless compression scheme. The algorithms for the individual stages of compression and decompression may also be of independent interest: 1. a novel O(log n)-time, O(n)-work PRAM algorithm for Huffman decoding; 2. original insights into the stages of the BW compression and decompression problems, bringing out parallelism that was not readily apparent. We then mapped such parallelism in interesting ways to elementary parallel routines that have O(log n)-time, O(n)-work solutions, such as: (i) prefix-sums problems with an appropriately-defined associative binary operator for several stages, and (ii) list ranking for the final stage of decompression (inverse blocksorting transform). Companion work reports empirical speedups of up to 25x for compression and up to 13x for decompression. This reflects a speedup of 70x over recent work on BW compression on GPUs.","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128136428","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":"Efficient scheduling to minimize calibrations","authors":"M. A. Bender, David P. Bunde, V. Leung, Samuel McCauley, C. Phillips","doi":"10.1145/2486159.2486193","DOIUrl":"https://doi.org/10.1145/2486159.2486193","url":null,"abstract":"Integrated Stockpile Evaluation (ISE) is a program to test nuclear weapons periodically. Tests are performed by machines that may require occasional calibration. These calibrations are expensive, so finding a schedule that minimizes calibrations allows more testing to be done for a given amount of money. This paper introduces a theoretical framework for ISE. Machines run jobs with release times and deadlines. Calibrating a machine requires unit cost. The machine remains calibrated for T time steps, after which it must be recalibrated before it can resume running jobs. The objective is to complete all jobs while minimizing the number of calibrations. The paper gives several algorithms to solve the ISE problem for the case where jobs have unit processing times. For one available machine, there is an optimal polynomial-time algorithm. For multiple machines, there is a 2-approximation algorithm, which finds an optimal solution when all jobs have distinct deadlines.","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128891464","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":"HEX: scaling honeycombs is easier than scaling clock trees","authors":"D. Dolev, Matthias Függer, C. Lenzen, Martin Perner, U. Schmid","doi":"10.1145/2486159.2486192","DOIUrl":"https://doi.org/10.1145/2486159.2486192","url":null,"abstract":"We argue that grid structures are a very promising alternative to the standard approach for distributing a clock signal throughout VLSI circuits and other hardware devices. Traditionally, this is accomplished by a delay-balanced clock tree, which distributes the signal supplied by a single clock source via carefully engineered and buffered signal paths. Our approach, termed HEX, is based on a hexagonal grid with simple intermediate nodes, which both control the forwarding of clock ticks in the grid and supply them to nearby functional units. HEX is Byzantine fault-tolerant, in a way that scales with the grid size, self-stabilizing, and seamlessly integrates with multiple synchronized clock sources, as used in multi-synchronous Globally Synchronous Locally Asynchronous (GALS) architectures. Moreover, HEX guarantees a small clock skew between neighbors even for wire delays that are only moderately balanced. We provide both a theoretical analysis of the worst-case skew and simulation results that demonstrate very small typical skew in realistic runs.","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125437785","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":"Parallel graph decompositions using random shifts","authors":"G. Miller, Richard Peng, S. Xu","doi":"10.1145/2486159.2486180","DOIUrl":"https://doi.org/10.1145/2486159.2486180","url":null,"abstract":"We show an improved parallel algorithm for decomposing an undirected unweighted graph into small diameter pieces with a small fraction of the edges in between. These decompositions form critical subroutines in a number of graph algorithms. Our algorithm builds upon the shifted shortest path approach introduced in [Blelloch, Gupta, Koutis, Miller, Peng, Tangwongsan, SPAA 2011]. By combining various stages of the previous algorithm, we obtain a significantly simpler algorithm with the same asymptotic guarantees as the best sequential algorithm.","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126293044","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":"Reduced hardware transactions: a new approach to hybrid transactional memory","authors":"A. Matveev, N. Shavit","doi":"10.1145/2486159.2486188","DOIUrl":"https://doi.org/10.1145/2486159.2486188","url":null,"abstract":"For many years, the accepted wisdom has been that the key to adoption of best-effort hardware transactions is to guarantee progress by combining them with an all software slow-path, to be taken if the hardware transactions fail repeatedly. However, all known generally applicable hybrid transactional memory solutions suffer from a major drawback: the coordination with the software slow-path introduces an unacceptably high instrumentation overhead into the hardware transactions. This paper overcomes the problem using a new approach which we call reduced hardware (RH) transactions. Instead of an all-software slow path, in RH transactions part of the slow-path is executed using a smaller hardware transaction. The purpose of this hardware component is not to speed up the slow-path (though this is a side effect). Rather, using it we are able to eliminate almost all of the instrumentation from the common hardware fast-path, making it virtually as fast as a pure hardware transaction. Moreover, the \"mostly software\" slow-path is obstruction-free (no locks), allows execution of long transactions and protected instructions that may typically cause hardware transactions to fail, allows complete concurrency between hardware and software transactions, and uses the shorter hardware transactions only to commit. Finally, we show how to easily default to a mode allowing an all-software slow-slow mode in case the \"mostly software\" slow-path fails to commit.","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131170410","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":"Universally truthful secondary spectrum auctions","authors":"M. Hoefer, Thomas Kesselheim","doi":"10.1145/2486159.2486163","DOIUrl":"https://doi.org/10.1145/2486159.2486163","url":null,"abstract":"We present algorithms for implementing local spectrum redistribution in wireless networks using a mechanism design approach. For example, in single-hop request scheduling, secondary users are modeled as rational agents that have private utility when getting assigned a channel for successful transmission. We present a simple algorithmic technique that allows to turn existing and future approximation algorithms and heuristics into truthful mechanisms for a large variety of networking problems. Our approach works with virtually all known interference models in the literature, including the physical model of interference based on SINR. It allows to address single-hop and multi-hop scheduling, routing, and even more general assignment and allocation problems. Our mechanisms are randomized and represent the first universally-truthful mechanisms for these problems with rigorous worst-case guarantees on the solution quality. In this way, our mechanisms can be used to obtain guaranteed solution quality even with risk-averse or risk-seeking bidders, for which existing approaches fail.","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121783430","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":"Storage and search in dynamic peer-to-peer networks","authors":"John E. Augustine, A. R. Molla, E. Morsy, Gopal Pandurangan, Peter Robinson, E. Upfal","doi":"10.1145/2486159.2486170","DOIUrl":"https://doi.org/10.1145/2486159.2486170","url":null,"abstract":"We study robust and efficient distributed algorithms for searching, storing, and maintaining data in dynamic Peer-to-Peer (P2P) networks. P2P networks are highly dynamic networks that experience heavy node churn (i.e., nodes join and leave the network continuously over time). Our goal is to guarantee, despite high node churn rate, that a large number of nodes in the network can store, retrieve, and maintain a large number of data items. Our main contributions are fast randomized distributed algorithms that guarantee the above with high probability even under high adversarial churn. In particular, we present the following main results: 1. A randomized distributed search algorithm that with high probability guarantees that searches from as many as n - o(n) nodes (n is the stable network size) succeed in O(log n )-rounds despite O(n/log1+δn) churn, for any small constant δ > 0, per round. We assume that the churn is controlled by an oblivious adversary (that has complete knowledge and control of what nodes join and leave and at what time and has unlimited computational power, but is oblivious to the random choices made by the algorithm). 2. A storage and maintenance algorithm that guarantees, with high probability, data items can be efficiently stored (with only θ(log n) copies of each data item) and maintained in a dynamic P2P network with churn rate up to O(n/log1+δn) per round. Our search algorithm together with our storage and maintenance algorithm guarantees that as many as n - o(n) nodes can efficiently store, maintain, and search even under O(n/log1+δn) churn per round. Our algorithms require only polylogarithmic in n bits to be processed and sent (per round) by each node. To the best of our knowledge, our algorithms are the first-known, fully-distributed storage and search algorithms that provably work under highly dynamic settings (i.e., high churn rates per step). Furthermore, they are localized (i.e., do not require any global topological knowledge) and scalable. A technical contribution of this paper, which may be of independent interest, is showing how random walks can be provably used to derive scalable distributed algorithms in dynamic networks with adversarial node churn.","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128579069","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":"Non-monetary fair scheduling: a cooperative game theory approach","authors":"P. Skowron, K. Rządca","doi":"10.1145/2486159.2486169","DOIUrl":"https://doi.org/10.1145/2486159.2486169","url":null,"abstract":"We consider a multi-organizational system in which each organization contributes processors to the global pool but also jobs to be processed on the common resources. The fairness of the scheduling algorithm is essential for the stability and even for the existence of such systems (as organizations may refuse to join an unfair system). We consider on-line, non-clairvoyant scheduling of sequential jobs. The started jobs cannot be stopped, canceled, preempted, or moved to other processors. We consider identical processors, but most of our results can be extended to related or unrelated processors. We model the fair scheduling problem as a cooperative game and we use the Shapley value to determine the ideal fair schedule. In contrast to the current literature, we do not use money to assess the relative utilities of jobs. Instead, to calculate the contribution of an organization, we determine how the presence of this organization influences the performance of other organizations. Our approach can be used with arbitrary utility function (e.g., flow time, tardiness, resource utilization), but we argue that the utility function should be strategy resilient. The organizations should be discouraged from splitting, merging or delaying their jobs. We present the unique (to within a multiplicative and additive constants) strategy resilient utility function. We show that the problem of fair scheduling is NP-hard and hard to approximate. However, for unit-size jobs, we present a fully polynomial-time randomized approximation scheme (FPRAS). We also show that the problem parametrized with the number of organizations is fixed parameter tractable (FPT). In cooperative game theory, the Shapley value is considered in many contexts as \"the\" fair solution. Our results show that, although the problem for the large number of organizations is computationally hard, this solution concept can be used in scheduling (for instance, as a benchmark for measuring fairness of heuristic algorithms).","PeriodicalId":353007,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Parallelism in algorithms and architectures","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124723761","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}