A Simd Approach to Large-Scale Real-Time System Air Traffic Control Using Associative Processor and Consequences for Parallel Computing
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A SIMD APPROACH TO LARGE-SCALE REAL-TIME SYSTEM AIR TRAFFIC CONTROL USING ASSOCIATIVE PROCESSOR AND CONSEQUENCES FOR PARALLEL COMPUTING A dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Man Yuan December 2012 Dissertation written by Man Yuan B.S., Hefei University of Technology, China 2001 M.S., University of Western Ontario, Canada 2003 Ph.D., Kent State University, 2012 Approved by Dr. Johnnie W. Baker , Chair, Doctoral Dissertation Committee Dr. Lothar Reichel , Members, Doctoral Dissertation Committee Dr. Mikhail Nesterenko Dr. Ye Zhao Dr. Richmond Nettey Accepted by Dr. Javed I. Khan , Chair, Department of Computer Science Dr. Raymond Craig , Dean, College of Arts and Sciences ii TABLE OF CONTENTS LISTOFFIGURES .................................. vii LISTOFTABLES ................................... ix Acknowledgements ................................... x 1 Introduction..................................... 1 2 BackgroundInformation . .. .. 7 2.1 Flynn’s Taxonomy and Classification . ... 7 2.1.1 Multiple Instruction Stream Multiple Data Stream (MIMD) ... 7 2.1.2 Single Instruction Stream Multiple Data Stream (SIMD)..... 8 2.2 Real-TimeSystems .............................. 10 2.3 AirTrafficControl(ATC) .......................... 13 2.3.1 TaskCharacteristics . 14 2.3.2 The worst-case environment of ATC . 14 2.3.3 ATCTasks .............................. 15 2.4 AnAssociativeProcessorforATC. .. 16 2.5 OpenMP.................................... 18 2.5.1 AvoidFalseSharing ......................... 20 2.5.2 OptimizeBarrierUse. 21 2.5.3 AvoidtheOrderedConstruct . 22 iii 2.5.4 AvoidLargeCriticalRegions . 22 2.5.5 MaximieParallelRegions . 22 2.5.6 Avoid Parallel Regions in Inner Loops . 23 2.5.7 ImproveLoadBalance . 24 2.5.8 Using Compiler Features to Improve Performance . .... 24 3 SurveyofLiterature................................ 26 3.1 PreviousWorkonATC............................ 26 3.2 Classical MIMD Real-Time Scheculing Theory . ..... 29 3.3 OtherSimilarWork.............................. 29 4 APSolutiontoATC ................................ 31 4.1 OverviewofAPSolution........................... 31 4.2 AdvantagesofAPoverMIMDforATC. 31 4.3 APproperties................................. 33 5 Emulating the AP on the ClearSpeed CSX600 . ... 37 5.1 OverviewofClearSpeedCSX600. 37 5.2 Emulating the AP on the ClearSpeed CSX600 . .. 39 6 ATCSystemDesign ................................ 41 6.1 ATCDataFlow................................ 41 6.2 StaticScheduling ............................... 41 6.3 Scaling up from CSX600 to a Realistic Size AP . ... 43 iv 7 AP Solution for ATC Tasks Implemented on CSX600 . .... 46 7.1 ReportCorrelationandTracking . .. 46 7.2 CockpitDisplay................................ 52 7.3 ControllerDisplayUpdate . 52 7.4 AutomaticVoiceAdvisory . 53 7.5 SporadicRequests............................... 53 7.6 Conflict Detection and Resolution (CD&R) . .... 53 7.6.1 ConflictDetection .......................... 53 7.6.2 ConflictResolution . .. .. 57 7.7 TerrainAvoidance .............................. 58 7.8 FinalApproach(Runways). 60 7.9 Comparison of AP and MIMD solutions for ATC Tasks . ... 61 7.10 Implementation of Algorithm Issues . ..... 63 8 ExperimentalResults............................... 65 8.1 ExperimentalSetup.............................. 65 8.2 ExperimentResults.............................. 67 8.2.1 Comparison of Performance on STI, MIMD and CSX600 . 67 8.2.2 Comparison of Performance on MIMD, CSX600 and STARAN . 68 8.2.3 How close to the AP is our CSX600 emulation of the AP . 70 8.2.4 Comparison of Predictability on CSX600 and MIMD . .. 72 8.2.5 Comparison of Missing Deadlines on CSX600 and MIMD . .. 73 8.2.6 Timingsfor8Tasks.......................... 73 v 8.2.7 VideoandActualSTARANDemos . 76 9 Observations and Consequences of the Preceding Results . .......... 78 10ConclusionsandFutureWork . .. 83 BIBLIOGRAPHY ................................... 89 vi LIST OF FIGURES 1 SIMDModel.................................. 9 2 APArchitecture................................ 17 3 Fork-JoinTaskModel ............................ 19 4 APossibleAPArchitectureforATC . 34 5 CSX600acceleratorboard .......................... 38 6 MTAParchitectureofCSX600. .. .. 38 7 Static schedule of ATC tasks implemented in AP . .. 43 8 Track/Reportcorrelation. 48 9 Searchboxsizeforflightmaneuver . 50 10 Conflictdetection............................... 56 11 Timingoftrackingtask. ........................... 68 12 Timingofterrainavoidancetask. .. 68 13 TimingofCD&Rtask. ............................ 69 14 Comparison of tracking task of MTI, CSX600 and STARAN. .... 69 15 Comparison of terrain avoidance task of MTI, CSX600 and STARAN. 70 16 Comparison of CD&R task of MTI, CSX600 and STARAN. 70 17 Comparison of display processing task of MTI, CSX600 and STARAN. 71 18 Time of tracking for number of aircraft from 10 to 384. ...... 71 19 Time of CD&Rfornumber ofaircraftfrom10to384. ... 72 vii 20 Comparison of MTI, STARAN and Super-CSX600 with at most one air- craftperPE. ................................. 72 21 Predictability of execution times for report correlation and tracking task. 73 22 Predictability of execution times for terrain avoidance task......... 73 23 Predictability of execution times for CD&R task. ...... 74 24 Number of iterations missing deadlines when scheduling tasks. ...... 74 25 OverallATCSystemDesign.. .. .. 98 viii LIST OF TABLES 1 Timings of Associative Functions . 40 2 StaticScheduleforATCTasks. .. .. 42 3 Statically Scheduled Solution Time for Worst Case Environment of ATC 45 4 Data Structures for Radar Reports ..................... 48 5 Data Structures for Tracks .......................... 49 6 ComparisonofRequiredATCOperations. 62 7 PerformanceofOneFlight/PE. .. .. 74 8 Performance of Eight Tasks for Ten Flights/PE . ... 75 ix Acknowledgements I would like to sincerely thank my advisor, Dr. Johnnie W. Baker, for his constant support and encouragement throughout my Ph.D. study. He has been the advisor for my research work throughout these years and also the mentor for my professional ca- reer development. Without his encouragement and guidance, this dissertation would be impossible. My special thanks will go to many people who have helped me at various stages of this work: Will Meilander, Frank Drews, Sue Peti, and Marcy Curtiss etc. In particular, Professor Will Meilander has contributed valuable information for my dissertation. He has read through all my publications and provided many useful comments. I would also like to thank my dissertation committee members for their willingness to serve on the committee and their valuable time. On a personal note, I would like to express my gratitude to my parents Zhen Yuan and Xiaohang Xu for their love and emotional support. Finally, I would like to express my thanks to my girl friend Sijin Zhang for her moral support and for the incredible amount of patience she had with me so that I can realize my dream eventually. x CHAPTER 1 Introduction The Air Traffic Control (ATC) system is a typical real-time system that continuously monitors, examines, and manages space conditions for thousands of flights by processing large volumes of data that are dynamically changing due to reports by sensors, pilots, and controllers, and gives the best estimate of position, speed and heading of every aircraft in the environment at all times. The ATC software consists of multiple real-time tasks that must be completed in time to meet their individual deadlines. By performing various tasks, the ATC system keeps timely correct information concerning positions, velocities, contiguous space conditions, etc., for all flights under control. Since any lateness or failure of task completion could cause disastrous consequences, time constraints for tasks are critical. [1–3] In the past, solutions to this problem have been implemented on multicomputer sys- tems with records for various aircraft stored in the memory accessible to the processors in this system. The dispersed nature of this dynamic ATC system and the necessity of maintaining data integrity while providing rapid access to this data by multiple instruc- tion streams (MIS) increases the difficulty and complexity of handling air traffic control. It is difficult for these MIMD implementations to satisfy reasonable predictability stan- dards that are critical for meeting the strict certification standards needed to ensure safety for critical software components. Massive efforts have been devoted to finding an efficient MIMD solution to the ATC problems since 1963 but none of them has been 1 2 satisfactory yet [4–7]. To a large degree, this is due to the fact that the software used by MIMDs in solving real-time problems involves solutions to many difficult problems such as dynamic scheduling, load balancing, etc [6]. It is currently widely accepted that large real-time problems such as ATC do not have a polynomial time MIMD solution [8, 9]. Even though many researchers have put extensive efforts into producing a reasonably good (e.g., using heuristic algorithms) solution to the ATC problem, the current ATC system has repeatedly failed to meet the requirements of the ATC automation system. It is frequently been reported that the current ATC system periodically loses radar data without any warnings and misses tracking of aircraft in the sky. This problem has even occurred with Air Force One. [3–5,7] Instead of using the traditional MIMD approach, we implement a prototype of the ATC system