Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures最新文献

{"title":"Session details: KEYNOTE LECTURE 1","authors":"M. Hajiaghayi","doi":"10.1145/3257323","DOIUrl":"https://doi.org/10.1145/3257323","url":null,"abstract":"","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128022576","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 Reissue Policies for Reducing Tail Latency","authors":"Tim Kaler, Yuxiong He, S. Elnikety","doi":"10.1145/3087556.3087566","DOIUrl":"https://doi.org/10.1145/3087556.3087566","url":null,"abstract":"Interactive services send redundant requests to multiple different replicas to meet stringent tail latency requirements. These additional (reissue) requests mitigate the impact of non-deterministic delays within the system and thus increase the probability of receiving an on-time response. There are two existing approaches of using reissue requests to reduce tail latency. (1) Reissue requests immediately to one or more replicas, which multiplies the load and runs the risk of overloading the system. (2) Reissue requests if not completed after a fixed delay. The delay helps to bound the number of extra reissue requests, but it also reduces the chance for those requests to respond before a tail latency target. We introduce a new family of reissue policies, Single-Time / Random (SingleR), that reissue requests after a delay d with probability q. SingleR employs randomness to bound the reissue rate, while allowing requests to be reissued early enough so they have sufficient time to respond, exploiting the benefits of both immediate and delayed reissue of prior work. We formally prove, within a simplified analytical model, that SingleR is optimal even when compared to more complex policies that reissue multiple times. To use SingleR for interactive services, we provide efficient algorithms for calculating optimal reissue delay and probability from response time logs through data-driven approach. We apply iterative adaptation for systems with load-dependent queuing delays. The key advantage of this data-driven approach is its wide applicability and effectiveness to systems with various design choices and workload properties. We evaluated SingleR policies thoroughly. We use simulation to illustrate its internals and demonstrate its robustness to a wide range of workloads. We conduct system experiments on the Redis key-value store and Lucene search server. The results show that for utilizations ranging from 40-60%, SingleR reduces the 99th-percentile latency of Redis by 30-$70% by reissuing only 2% of requests, and the 99th-percentile latency of Lucene by 15-25% by reissuing 1% only.","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134276518","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":"Brief Announcement: Meeting the Challenges of Parallelizing Sequential Programs","authors":"Rohit Atre, A. Jannesari, F. Wolf","doi":"10.1145/3087556.3087592","DOIUrl":"https://doi.org/10.1145/3087556.3087592","url":null,"abstract":"Discovering which code sections in a sequential program can be made to run in parallel is the first step in parallelizing it, and programmers routinely struggle in this step. Most of the current parallelism discovery techniques focus on specific language constructs while trying to identify such code sections. In contrast, we propose to concentrate on the computations performed by a program. In our approach, a program is treated as a collection of computations communicating with one another using a number of variables. Each computation is represented as a Computational Unit (CU). A CU contains the inputs and outputs of a computation, and the three phases of a computation: read, compute, and write. Based on the notion of CU, We present a unified framework to identify both loop and task parallelism in sequential programs.","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"245 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134357339","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":"Brief Announcement: Hardware Transactional Storage Class Memory","authors":"Ellis R. Giles, K. Doshi, P. Varman","doi":"10.1145/3087556.3087589","DOIUrl":"https://doi.org/10.1145/3087556.3087589","url":null,"abstract":"Emerging persistent memory technologies (generically referred to as Storage Class Memory or SCM) hold tremendous promise for accelerating popular data-management applications like in-memory databases. However, programmers now need to deal with ensuring the atomicity of transactions on SCM-resident data and maintaining consistency between the persistent and in-memory execution orders of concurrent transactions. The problem is specially challenging when high-performance isolation mechanisms like Hardware Transaction Memory (HTM) are used for concurrency control. In this work we show how SCM-based HTM transactions can be ordered correctly using existing CPU instructions, without requiring any changes to existing processor cache hardware or HTM protocols. We describe a method that employs HTM for concurrency control and enforces atomic persistence and consistency with a novel software protocol and back-end external memory controller. In contrast, previous approaches require significant hardware changes to existing processor microarchitectures.","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117029601","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":"Session details: SESSION 2","authors":"M. Goodrich","doi":"10.1145/3257325","DOIUrl":"https://doi.org/10.1145/3257325","url":null,"abstract":"","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125808827","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 Local Buffer Management for Information Gathering with Adversarial Traffic","authors":"S. Dobrev, Manuel Lafond, L. Narayanan, J. Opatrny","doi":"10.1145/3087556.3087577","DOIUrl":"https://doi.org/10.1145/3087556.3087577","url":null,"abstract":"We consider a problem of routing on directed paths and trees to a single destination, with rate-limited, adversarial traffic. In particular, we focus on local buffer management algorithms that ensure no packet loss, while minimizing the size of the required buffers. While a centralized algorithm for the problem that uses constant-sized buffers has been recently shown [21], there is no known local algorithm that achieves a sub-linear buffer size. In this paper we show tight bounds for the maximum buffer size needed by l-local algorithms for information gathering on directed paths and trees, where an algorithm is called l-local if the decision made by each node v depends only on the sizes of the buffers at most l hops away from v. We show three main results: A lower bound of Ω(c log n/l) for all l-local algorithms on both directed and undirected paths, where c is an upper bound on the link capacity and injection rate. A surprisingly simple 1-local algorithm for directed paths that uses buffers of size O(log n), when c=1. A natural 2-local extension of this algorithm to directed trees, for c=1, with the same asymptotic bound. Our Ω(log n) lower bound is significantly lower than the Ω(n) lower bound for greedy algorithms, and perhaps surprisingly, there is a matching upper bound. The algorithm that achieves it can be summarized in two lines: If the size of your buffer is odd, forward a message if your successor's buffer size is equal or lower. If your buffer size is even, forward a message only if your successor's buffer size is strictly lower. For trees, a simple arbitration between siblings is added.","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126734102","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":"Session details: SESSION 6","authors":"F. Dehne","doi":"10.1145/3257330","DOIUrl":"https://doi.org/10.1145/3257330","url":null,"abstract":"","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129463658","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":"The Mobile Server Problem","authors":"Björn Feldkord, F. Heide","doi":"10.1145/3087556.3087575","DOIUrl":"https://doi.org/10.1145/3087556.3087575","url":null,"abstract":"We introduce the mobile server problem, inspired by current trends to move computational tasks from cloud structures to multiple devices close to the end user. An example for this are embedded systems in autonomous cars that communicate in order to coordinate their actions. Our model is a variant of the classical Page Migration Problem. More formally, we consider a mobile server holding a data page. The server can move in the Euclidean space (of arbitrary dimension). In every round, requests for data items from the page pop up at arbitrary points in the space. The requests are served, each at a cost of the distance from the requesting point and the server, and the mobile server may move, at a cost D times the distance traveled for some constant D. We assume a maximum distance m the server is allowed to move per round. We show that no online algorithm can achieve a competitive ratio independent of the length of the input sequence in this setting. Hence we augment the maximum movement distance of the online algorithms to (1+δ) times the maximum distance of the offline solution. We provide a deterministic algorithm which is simple to describe and works for multiple variants of our problem. The algorithm achieves almost tight competitive ratios independent of the length of the input sequence.","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123870050","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":"Bounding Laconic Proof Systems by Solving CSPs in Parallel","authors":"Jason Li, R. O'Donnell","doi":"10.1145/3087556.3087557","DOIUrl":"https://doi.org/10.1145/3087556.3087557","url":null,"abstract":"We show that the basic semidefinite programming relaxation value of any constraint satisfaction problem can be computed in NC; that is, in parallel polylogarithmic time and polynomial work. As a complexity-theoretic consequence we get that MIPone[k,c,s] subseteq PSPACE provided s/c leq (.62-o(1))k/2^k, resolving a question of Austrin, Haa stad, and Pass. Here MIPone[k,c,s] is the class of languages decidable with completeness c and soundness s by an interactive proof system with k provers, each constrained to communicate just 1 bit.","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122240302","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":"Brief Announcement: Hazard Eras - Non-Blocking Memory Reclamation","authors":"P. Ramalhete, Andreia Correia","doi":"10.1145/3087556.3087588","DOIUrl":"https://doi.org/10.1145/3087556.3087588","url":null,"abstract":"For non-blocking data-structures, only memory reclamation with pointer-based techniques can maintain non-blocking progress, but there can be high overhead associated to these techniques, with the most notable example being Hazard Pointers. We present a new algorithm we named Hazard Eras, which allows for efficient lock-free or wait-free memory reclamation in concurrent data structures and can be used as drop-in replacement to Hazard Pointers. Results from our microbenchmark show that when applied to a lock-free linked list, Hazard Eras will match the throughput of Hazard Pointers in the worst-case, and can outperform Hazard Pointers by a factor of 5x. Hazard Eras provides the same progress conditions as Hazard Pointers and can equally be implemented with the C11/C++11 memory model and atomics, making it portable across multiple systems.","PeriodicalId":162994,"journal":{"name":"Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122676393","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}