2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)最新文献

{"title":"Modelling Performance Loss due to Thread Imbalance in Stochastic Variable-Length SIMT Workloads","authors":"Stephen Nicholas Swatman, A. Varbanescu, A. Krasznahorkay, A. Pimentel","doi":"10.1109/MASCOTS56607.2022.00026","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00026","url":null,"abstract":"When designing algorithms for single-instruction multiple-thread (SIMT) devices such as general purpose graphics processing units (GPGPUs), thread imbalance is an important performance consideration. Thread imbalance can emerge in iterative applications where workloads are of variable length, because threads processing larger amounts of work will cause threads with less work to idle. This form of thread imbalance influences the design space of algorithms-particularly in terms of processing granularity-but we lack models to quantify its impact on application performance. In this paper, we present a statistical model for quantifying the performance loss due to thread imbalance for iterative SIMT applications with stochastic, variable-length workloads. Our model is designed to operate with minimal knowledge of the implementation details of the algorithm, relying solely on an understanding of the probability distribution of the lengths of the workloads. We validate our model against a synthetic benchmark based on a Monte Carlo simulation of matrix exponentiation, and show that our model achieves nearly perfect accuracy. Compared to empirical data extracted from real hardware, our model maintains a high degree of accuracy, predicting mean performance loss within a margin of 2%.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"211 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123389333","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":"LoRaLitE: LoRa protocol for Energy-Limited environments","authors":"Lukasz Sergiusz Michalik, Loic Guegan, Issam Raïs, Otto J. Anshus, J. Bjørndalen","doi":"10.1109/MASCOTS56607.2022.00018","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00018","url":null,"abstract":"To do in-situ observations of the arctic tundra, many small sensor nodes are used. Reporting the data to remote back-ends is hard because backhaul networks are scarce, and a node cannot expect to see one. Also, there are typically no humans physically close to the nodes to fetch the data and to replace batteries. Consequently, the nodes need a highly available, energy-efficient long range network. While LoRaWAN provides energy-efficient communication for nodes, it does so at the cost of needing an always-on gateway with a high energy consumption. The gateway is also a single point of failure. Instead we propose LoRaLitE for Energy-Limited environments where the gateway enters sleep phases to reduce energy consumption. The sleep phases of the nodes are coordinated accordingly. For high availability, any end-node with a backhaul-network can be elected to become the gateway. We conducted a series of simulation experiments to document the performance behavior of both LoRaWanand LoRaLitE. The results show that the LoRaLitE gateway spends from 10 to 10,000 times less energy than a LoRaWAN gateway. A LoRaLitE node spends from 13% to 42% more energy than a LoRaWAN node. The achievable bandwidth for LoRaLitE is only insignificantly smaller than for LoRaWAN. A LoRaWangateway needs a relatively large, heavy battery. If the gateway fails, assuming a new gateway can be elected, several nodes must have similar large batteries to be able to take over as the gateway. This is impractical to achieve for more than a few nodes because the nodes become more expensive, harder to camouflage, and impractical to deploy. A LoRaLitE gateway on the other hand only needs a battery like any other node. Even if all nodes need larger batteries than for the LoRaWancase, the increase is in practical terms insignificant. We conclude that LoRaLitE makes it realistic to use LoRa for nodes on the arctic tundra, providing for insignificant increased energy usage at the nodes, insignificant reduced bandwidth, but with significant increase in gateway availability. LoRaLitE also provides for an easier deployment in practice because all nodes can be kept small and light,","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132190349","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":"Tracking a Mobile Beacon: A Purely Probabilistic Approach","authors":"F. Daníş, Cem Ersoy, A. Cemgil","doi":"10.1109/MASCOTS56607.2022.00029","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00029","url":null,"abstract":"We construct a practical and real-time probabilistic framework for fine target tracking. The practicality comes from the application of the forward algorithm and the small parameter set used to build the hidden Markov model (HMM). A Bluetooth Low-Energy (BLE) beacon navigating in the environment publishes BLE packets which are captured by the stationary sensors. Fingerprints are formed by collecting received signal strength indicators (RSSI) of these packets, which are then processed into a high resolution emission matrix using a histogram combination technique. We convert the map of the area into a grid structure, the resolution of which is controlled by the grid cell size. The transition matrices are built by Gaussian blur masks parametrized by the size and diffusion extent. As the transition matrix is highly sparse, we make the exact inference tractable by adopting a sparse matrix representation and by intelligently controlling the mask size, diffusion factor and grid cell size. Filtering can then be directly performed by the forward algorithm given a series of real RSSI measurements along real trajectories. We measure the performance of the system by comparing the most likely positions at each step with the ground truth positions. We achieve promising results and evaluate the approach also by the runtime and memory usage.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"63 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120928158","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":"DTS: A Simulator to Estimate the Training Time of Distributed Deep Neural Networks","authors":"Flavio Esposito, Maria A. Zuluaga","doi":"10.1109/MASCOTS56607.2022.00011","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00011","url":null,"abstract":"Deep Neural Networks (DNNs) process big datasets achieving high accuracy on incredibly complex tasks. However, this progress has led to a scalability impasse, as DNNs require massive amounts of processing power and local memory to be trained, making them impossible or impractical to be used on a single device. This situation has led to the design of distributed training architectures, where the DNN and the training data can be split among multiple processors. How to choose the appropriate distributed training architecture, however, remains an open question. To help bring insights into this debate, in this work we design a Distributed Training Simulator (DTS) that estimates the training time of a DNN in a distributed architecture through a mathematical model of the distributed architecture and resource-allocation heuristics. We illustrate the power of the proposed DTS through the implementation of five different distributed architectures, Pipeline Learning, Federated Learning, Split Learning, Parallel Split Learning, and Federated Split Learning, and we validate the accuracy of the training estimates using three different datasets of varying complexity and two different DNNs. Finally, we present a trade-off analysis to demonstrate the coherence of DTS estimates for diverse high-performance computing scenarios by comparing these estimates with the behaviors of a real computer cluster.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121104741","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":"Cross-Level Characterization of Program Execution","authors":"Li Tang, S. Pakin","doi":"10.1109/MASCOTS56607.2022.00013","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00013","url":null,"abstract":"Characterization of program execution plays a key role in performance improvement. There are numerous transformations applied to each step a program takes on its lowering from source code to a compiler intermediate representation to machine language to microarchitecture-specific execution. The unpredictable benefit of each transformation step could lead a notionally superior algorithm to exhibit inferior performance once actually run, and it can be opaque at what step in the transformation path contradicted the code developer's assumptions. However, conventional approaches to program execution characterization consider the behavior after only a single one of those steps, which limits the information that can be provided to the user. To help address the issue of myopic views of program execution, this paper presents a novel cross-level characterization approach for understanding the behavior of program execution at different levels in the process of writing, compiling, and running a program. We show that this approach provides a richer view of the sources of performance gains and losses and helps identify program execution in a more accurate manner.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123760318","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":"G-Networks Can Detect Different Types of Cyberattacks","authors":"Erol Gelenbe, Mert Nakɩp","doi":"10.1109/MASCOTS56607.2022.00010","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00010","url":null,"abstract":"Malicious network attacks are a serious source of concern, and machine learning techniques are widely used to build Attack Detectors with off-line training with real attack and non-attack data, and used online to monitor system entry points connected to networks. Many machine learning based Attack Detectors are typically trained to identify specific types attacks, and the training of such algorithms to cover several types of attacks may be excessively time consuming. This paper shows that G-Networks, which are queueing networks with product form solution and special customers such as negative customers and triggers, can be trained just with “non-attack” traffic, can accurately detect several different attack types. This is established with a special case of G-Networks with triggerred customer movement. A DARPA attack and non-attack traffic repository is used to train and test the the G-Network, yielding comparable or clearly better accuracy than most known attack detection techniques.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132873300","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":"Modelling Energy Changes in the Energy Harvesting Battery of an IoT Device","authors":"T. Czachórski, Erol Gelenbe, Godlove Suila Kuaban","doi":"10.1109/MASCOTS56607.2022.00019","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00019","url":null,"abstract":"The complexity of battery-powered autonomous devices such as Internet of Things (IoT) nodes or Unmanned Aerial Vehicles (UAV) and the necessity to ensure an acceptable quality of service, reliability, and security, have significantly increased their energy demand. In this paper, we discuss using a diffusion approximation process to approximate the dynamic changes in the energy content of a battery. We consider the case when energy harvesting sources are constantly charging the battery. The model assumes a probabilistic consumption and delivery of energy, giving the time-dependent distributions of the energy at the battery, of the time remaining until it becomes empty, the time required to charge the battery to its total capacity, or the time it is operational between two moments of complete depletion. When possible, we compare the diffusion approximation results with corresponding models based on continuous-time Markov chains.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115181287","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":"Design and Simulation of Multi-tiered Heterogeneous Memory Architecture","authors":"Jinyuan Hu, Haikun Liu, Hai Jin, Xiaofei Liao","doi":"10.1109/MASCOTS56607.2022.00023","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00023","url":null,"abstract":"Heterogeneous memory systems have become increasingly popular in recent years. Because heterogeneous storage media often show significantly different characteristics in terms of bandwidth, latency, capacity, and energy consumption, it is still challenging to best utilize them for cost-efficient and energy-efficient heterogeneous memory systems. In this paper, we propose a simulation framework for multi-tiered heterogeneous memory architectures based on GEM5 and DRAMsim3 simulators. We design a heterogeneous memory controller to architect Non-Volatile Memory (NVM) as main memory, and architect both Dynamic Random Access Memory (DRAM) and High-Bandwidth Memory (HBM) as a hybrid cache of NVM. Specifically, HBM, DRAM, and NVM are managed in a single (flat) address space. However, we use an address remapping table to maintain the mappings between NVM pages and HBM/DRAM pages, and logically manage HBM/DRAM/NVM as a three-tiered hybrid memory system. We also design a hardware-supported hot page monitor based on Majority Element Algorithm (MEA) to identify the hottest pages in the DRAM, and a dynamic threshold adjustment scheme for hot page migration to balance the memory bandwidth between DRAM and HBM. Our multi-tiered heterogeneous memory architecture can take advantage of the large capacity of NVM, the low latency of DRAM, and the high bandwidth of HBM concurrently. Experimental results show that our tiered memory architecture can improve application performance by an average of $2.5times$ compared with an NVM-only architecture, and up to 57.4% compared with a DRAM-only architecture. Moreover, the performance gap between our HBM/DRAM/NVM architecture and a HBM-only architecture is less than 10%.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114291903","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":"Truncating Multi-Dimensional Markov Chains With Accuracy Guarantee","authors":"Gagan Somashekar, Mohammad Delasay, Anshul Gandhi","doi":"10.1109/MASCOTS56607.2022.00024","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00024","url":null,"abstract":"The ability to obtain the steady-state probability distribution of a Markov chain is invaluable for modern service providers who aim to satisfy arbitrary tail performance requirements. However, it is often challenging and even intractable to obtain the steady-state distribution for several classes of Markov chains, such as multi-dimensional and infinite state-space Markov chains with state-dependent transitions. Two examples include the M/M/1 with Discriminatory Processor Sharing (DPS) and the preemptive M/M/c with multiple priority classes and customer abandonment. This paper proposes a Lyapunov function-based state-space truncation technique for such Markov chains. Our technique leverages the available moments, or bounds on moments, of the state variables of the Markov chain to obtain tight truncation bounds while satisfying arbitrary probability mass guarantees for the truncated chain. We demonstrate the efficacy of our technique for the multi-dimensional DPS and M/M/c priority queue with abandonment and highlight the significant reduction in state space (as much as 72%) afforded by our approach compared to the state-of-the-art.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127536545","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":"DB-LBT: Deterministic Backoff with Listen Before Talk for Wi-Fi/NR-U Coexistence in Shared Bands","authors":"Katarzyna Kosek-Szott, S. Szott, Alice Lo Valvo, I. Tinnirello","doi":"10.1109/MASCOTS56607.2022.00030","DOIUrl":"https://doi.org/10.1109/MASCOTS56607.2022.00030","url":null,"abstract":"The legacy approach to solve coexistence problems between multiple wireless networks operating in the same frequency bands is through network planning. However, this approach is often unfeasible in unlicensed (shared) bands, where different network owners and technologies work without any coordination. In this paper, we adapt an existing channel access scheme for fair resource sharing between Wi-Fi and NR-U (the unlicensed version of 5G), in a completely distributed manner. The idea is to find an ordered schedule of transmissions granted to the active transmitters (regardless of their technology) and repeat this schedule in a round-robin fashion until the set of active transmitters changes. The mechanism works as a special extension of a random access scheme with deterministic backoff counters. Simulation-based results prove that the scheme guarantees airtime fairness between network cells and technologies while optimizing channel efficiency and minimizing channel access delays. Unlike other coexistence solutions, the scheme does not require the exchange of information between the coexisting cells; moreover, it is backward compatible with legacy access schemes.","PeriodicalId":220026,"journal":{"name":"2022 30th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125506560","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}