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30th Symposium on Principles and Practice of parallel Programming

作者： Liu, Zhengqing Unal, Musa Parkinson, Matthew J. Kogias, Marios Imperial Coll London London England Ecole Polytech Fed Lausanne Lausanne Switzerland Azure Res Austin TX USA

ISBN: (纸本)9798400714436

Deterministic parallelism is a key building block for distributed and fault-tolerant systems that offers substantial performance benefits while guaranteeing determinism. By studying existing deterministically parallel systems (DPS), we identify certain design pitfalls, such as batched execution and inefficient runtime synchronization, that preclude them from meeting the demands of mu s-scale and high-throughput distributed systems deployed in modern datacenters. We present DORADD, a deterministically parallel runtime with low latency and high throughput, designed for modern datacenter services. DORADD introduces a hybrid scheduling scheme that effectively decouples request dispatching from execution. It employs a single dispatcher to deterministically construct a dynamic dependency graph of incoming requests and worker pools that can independently execute requests in a work-conserving and synchronization-free manner. Furthermore, DORADD overcomes the single-dispatcher throughput bottleneck based on core pipelining. We use DORADD to build an in-memory database and compare it with Caracal, the current state-of-the-art deterministic database, via the YCSB and TPC-C benchmarks. Our evaluation shows up to 2.5x better throughput and more than 150x and 300x better tail latency in non-contended and contended cases, respectively. We also compare DO-RADD with Caladan, the state-of-the-art non-deterministic remote procedure call (RPC) scheduler, and demonstrate that determinism in DORADD does not incur any performance overhead.

关键词： parallel execution determinism runtime scheduling

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Algebraic computational models of OR-parallel execution of Prolog

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ACTA INFORMATICA 1997年第6期34卷 449-489页

作者： Barbuti, R DeFrancesco, N Santone, A UNIV PISA DIPARTIMENTO INGN INFORMAZ I-56125 PISA ITALY

A specification of the OR-parallel execution of Prolog programs, using CHOCS (calculus of higher order communicating systems) [24], is presented in the paper. A translation is defined from Prolog programs and goals to CHOCS processes: the execution of the CHOCS process corresponding to a goal mimics the OR-parallel execution of the original Prolog goal. In the translation, clauses and predicate definitions of a Prolog program correspond to processes. To model OR-parallelism, the processes P-1,...,P-n, corresponding to clauses C-1,...,C-n (having the same head predicate p) start their execution concurrently, but, in order to respect the depth-first search rule, each P-i is guarded by the termination of the executions of processes p(j')s, j < i. The computational model is proved correct with respect to the semantics of Prolog, as given in [4, 5]. Our model, because of its algebraic specification, can be easily used to prove properties of the parallel execution of Prolog programs. Moreover, the model exploits the maximum degree of parallelism, by giving the Prolog solutions in parallel, without any order among them. However, this model, being close to the Prolog semantics definition, contains sources of inefficiency which make it unpractical as a guide for the implementation. To overcome these problems, a new computational model is defined. This model is obtained by modifications of the basic one and thus its correctness can be easily proved. Finally, rye show how to obtain models of different real implementations of OR-parallel Prolog by slight modification of the new model. The relations among all these models, in terms of parallelism degree, are studied by using the concepts of bisimulation and simulation, developed for concurrent calculi.

关键词： Computational Model Slight Modification Maximum Degree parallel execution Real Implementation

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Segmented Storage Based on parallel execution for IoT Blockchains

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IEEE INTERNET OF THINGS JOURNAL 2024年第21期11卷 35206-35222页

作者： Li, Jin Lu, Yueming Zeng, Yuli Guo, Ziyu Beijing Univ Posts & Telecommun Minist Educ Key Lab Trustworthy Distributed Comp & Serv Beijing 100876 Peoples R China State Grid Hebei Elect Power Res Inst Energy Digital Technol Res Ctr Shijiazhuang 050021 Peoples R China

Internet of Things (IoT) blockchains are characterized by the difference in storage resources, computing power, and high dynamic of node topologies. In view of the demand for short-time and high-concurrency execution of events in IoT blockchain transaction scenarios, we propose a lightweight segmented storage based on parallel execution for IoT blockchains. This method breaks through the technical difficulties of 2-D ledger design for event parallelism, de-blocking lightweight synchronization of cross-domain data, and global consistency maintenance of asynchronous ledger, and achieves parallel execution of events and lightweight segmented storage of resource-constrained nodes. First, the event cumulative verification and differential generation algorithm is proposed to reduce the redundancy propagation in event distribution and voting. Second, the effective concurrent consensus confirmation mechanism of events is proposed to implement the distributed batch confirmation of valid events, which guarantees the low-latency confirmation of events. Furthermore, the data lightweight segmented storage mechanism is proposed to implement the data lightweight segmented storage of the resource-constrained nodes combined with the design of the LBPS Chain ledger structure. Simulation results show that the LBPS Chain outperforms LDV, Layerchain, and GpDB by 85%, 88%, and 52% in terms of storage cost. Compared to the Hashgraph, our method effectively increases the throughput by 89% and has scalability in reducing the storage cost and increasing throughput.

关键词： Blockchains Internet of Things Throughput Synchronization Costs Sharding Periodic structures Blockchain directed acyclic graph (DAG) lightweight storage parallel execution

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Policy-Aware Service Composition: Predicting parallel execution Performance of Composite Services

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IEEE TRANSACTIONS ON SERVICES COMPUTING 2018年第4期11卷 602-615页

作者： Trang, Mai Xuan Murakami, Yohei Ishida, Toru Kyoto Univ Dept Social Informat Kyoto Japan Kyoto Univ Design Sch Kyoto Japan

With the increasing volume of data to be analysed, one of the challenges in Service Oriented Architecture (SOA) is to make web services efficient in processing large-scale data. parallel execution and cloud technologies are the keys to speed-up the service invocation. In SOA, service providers typically employ policies to limit parallel execution of the services based on arbitrary decisions. In order to attain optimal performance improvement, users need to adapt to the services policies. A composite service is a combination of several atomic services provided by various providers. To use parallel execution for greater composite service efficiency, the degree of parallelism (DOP) of the composite services need to be optimized by considering the policies of all atomic services. We propose a model that embeds service policies into formulae to calculate composite service performance. From the calculation, we predict the optimal DOP for the composite service, where it attains the best performance. Extensive experiments are conducted on real-world translation services. We use several measures such as mean prediction error (MPE), mean absolute deviation (MAD) and tracking signal (TS) to evaluate our model. The analysis results show that our proposed model has good prediction accuracy in identifying optimal DOPs for composite services.

关键词： Service policy service composition parallel execution degree of parallelism performance prediction

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Method of adaptive controllable parallel execution of operations in object database management systems

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PROGRAMMING AND COMPUTER SOFTWARE 2008年第1期34卷 7-15页

作者： Samarev, R. S. Bauman State Tech Univ Moscow 105005 Russia

The design of parallel database management systems (DBMSs) normally implies using special-purpose multiprocessor computing systems. Most often, a DBMS is supposed to work in an exclusive mode of operation. However, in the class of x86-based multiprocessor computing systems designed for mass usage, the exclusive mode of DBMS operation with respect to other software is often not secured. In addition, the legacy software for this class of computing systems is often not designed for mass parallel usage. When the exclusive mode requirement is ignored and the resources of the computing system are not used in low-load DBMS regimes, the efficiency of using resources of the computing system as a whole reduces. This paper considers a method of program organization of controlled parallelism at the level of internal DBMS operations, allowing for their controlled execution based on the state of the entire computing system. This method made it possible to significantly reduce the time of response for low densities of query arrival in the ODB-Jupiter commercial object DBMS developed in the Inteltec Plus scientific manufacturing center. The method of controlled parallel execution can be used in a wide class of program systems.

关键词： PROGRAM ORGANIZATIONS Multiprocessor database management systems Reaction Time legacy software operation mode parallel execution Surgery

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Toward Bounds on parallel execution Times of Task Graphs on Multicores With Memory Constraints

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IEEE ACCESS 2019年 7卷 52778-52789页

作者： Song, Jiangong Li, Qinyong Ma, Shilong Beihang Univ State Key Lab Software Dev Environm Beijing 100083 Peoples R China

As more and more parallel programs are migrating to shared computing platforms, bounding their parallel execution times under resource constraints is particularly important for their efficient executions. The parallel program is often modeled as a task graph, which is composed of a collection of control or data-dependent sub-tasks organized as a directed acyclic graph (DAG) for scheduling. In this paper, we propose a simple yet effective method to bound the parallel execution time of a task graph when the memory resources are constrained. The essence of this method is to extend Brent's theorem by incorporating the memory factor. To this end, we introduce a concept of range of concurrent tasks (RCT) and leverage it to estimate an upper bound on the parallel execution time of task graph with respect to work-conserving scheduling algorithm. And also we exploit the estimated bound to develop a metric to help determine optimal memory capacity for a given task graph. Through an empirical study, we evaluate how good the estimated bound is via a designed scheduling algorithm and demonstrate the effectiveness of the metric in the selection of optimal memory capacity for a task graph.

关键词： Task graph scheduling time bounds parallel execution multicores shared memory memory constraints

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Evaluating the parallel execution Schemes of Smart Contract Transactions in Different Blockchains: An Empirical Study 21st

Evaluating the Parallel Execution Schemes of Smart Contract ...

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21st International Conference on Algorithms and Architectures for parallel Processing (ICA3PP)

作者： Shi, Jianfeng Li, Chengzhi Wu, Heng Gao, Heran Jin, Songchang Huang, Tao Zhang, Wenbo Univ Chinese Acad Sci Beijing Peoples R China Chinese Acad Sci Inst Software Beijing Peoples R China Chinese Acad Sci Inst Software State Key Lab Comp Sci Beijing Peoples R China Def Innovat Inst Beijing Peoples R China Tianjin Artificial Intelligence Innovat Ctr Tianjin Peoples R China

ISBN: (纸本)9783030953911;9783030953904

In order to increase throughput, more and more blockchains begin to provide the ability to execute smart contract transactions in parallel. However, there is currently no research work on evaluating parallel execution schemes in different blockchains, which makes it difficult for developers to find a blockchain technology suitable for their application scenarios. In this paper, we firstly summarize existing parallel execution schemes of smart contract transactions. Then, based on their characteristics, we propose a comprehensive evaluation framework for parallel execution schemes of smart contract transactions and implement a benchmark tool, which can compare different parallel execution schemes and discover their limitations. Finally, we utilize the evaluation framework and the tool to evaluate several excellent blockchains in China and obtain some useful findings.

关键词： Blockchain Smart contract parallel execution Benchmark Empirical study

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Modeling parallel execution Policies of Web Services 6th

Modeling Parallel Execution Policies of Web Services

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6th International Conference on Cloud Computing (CloudComp)

作者： Trang, Mai Xuan Murakami, Yohei Ishida, Toru Kyoto Univ Dept Social Informat Kyoto Japan Kyoto Univ Unit Design Kyoto Japan

ISBN: (纸本)9783319389042;9783319389035

Cloud computing and high performance computing enable service providers to support parallel execution of provided services. Consider a client who invokes a web service to process a large dataset. The input data is split into independent partitions and multiple partitions are sent to the service concurrently. A typical customer would expect the service speedup to be directly proportional to the number of concurrent requests (or the degree of parallelism - DOP). However, we obtained that the achieved speedup is not always directly proportional to the DOP. This may because service providers employ parallel execution policies for their services based on arbitrary decisions. The goal of this paper is to analyse the performance improvement behavior of web services under parallel execution. We introduce a model of parallel execution policy of web services with three policies: Slow-down, Restriction and Penalty policies. We conduct analyses to evaluate our model. Interestingly, the results show that our model have a good accuracy in capturing parallel execution behavior of web services.

关键词： parallel execution Service policy Performance analysis

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Excluding parallel execution to Improve Global Fixed Priority Response Time Analysis

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ACM TRANSACTIONS ON EMBEDDED COMPUTING SYSTEMS 2021年第5期20卷 104-104页

作者： Zhou, Quan Li, Jianjun Li, Guohui Huazhong Univ Sci & Technol Luoyu Rd 10375 Wuhan 430074 Hubei Peoples R China

Response Time Analysis (RTA) is an effective method for testing the schedulability of real-time tasks on multiprocessor platforms. Existing RTAs for global fixed priority scheduling calculate the upper bound of the worst case response time of each task. Given a target task, existing RTAs first calculate the workload upper bound of each higher priority task (than the target task), and then calculate the interference on the target task by each higher priority task according to the obtained workload upper bounds. The workload of a task consists of three parts: carry-in, body and carry-out. The interference from all these three parts may be overestimated in existing RTAs. However, although the overestimation of the interference from body is the major factor that causes the low accuracy of existing RTAs, all existing work only focuses on how to reduce the overestimation of the interference from carry-in, and there is no method to reduce the overestimation of the interference from body or carry-out. In this work, we propose a method to calculate the lower bound of the accumulative time in which the target task and higher priority tasks are executed in parallel. By excluding the parallel execution time from the interference, we derive a new RTA test that can reduce the overestimation of the interference from all three parts of the workload. Extensive experiments are conducted to verify the superior performance of the proposed RTA test.

关键词： Response time analysis global scheduling real-time systems multiprocessor parallel execution

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Fully-automated Instance Decomposition and Subplan Synthesis for parallel execution

Fully-automated Instance Decomposition and Subplan Synthesis...

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25th IEEE International Conference on Tools with Artificial Intelligence (ICTAI)

作者： Mali, Amol D. Puthiyattil, Ravi Univ Wisconsin EECS Milwaukee WI 53211 USA Demat Mat Handling Syst New Berlin WI 53151 USA

ISBN: (纸本)9781479929719

Subplans with limited interactions can be executed in a parallel and flexible manner. Given the success of SAT planning in the international planning competitions in 2004 and 2006 and advances in SAT solving, it is worth investigating how SAT planning can be used to generate plans for execution by multiple agents. We report on SAT encodings that have a model if and only if there are n subplans, each with up to k steps, such that they together achieve the goal and also satisfy the encoded criteria about permitted and prohibited interactions among them. These n subplans can be executed by different agents. Our SAT-based approach decomposes a planning instance fully automatically in an entirely unfamiliar domain with no knowledge from humans, if a decomposition exists. Desired properties of decomposition and solution are encoded as SAT. The key ideas in our encodings are an allocation of actions and subgoals to various agents and explanatory frame axioms for multiple agents. No domain-specific knowledge is used. We report on an empirical evaluation of the encodings. Our approach is domain-independent and fully automated. We discuss variants of our encodings.

关键词： Distributed Planning Multiagent Planning parallel Planning Plan Merging SEMI-AUTOMATIC TRIM College Entrance Examination Board Scholastic Aptitude Test decomposition Agents parallel execution Planning Legal executions

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