VIRTUAL TIME-AWARE VIRTUAL MACHINE SYSTEMS A Dissertation Presented to The Academic Faculty by Srikanth B. Yoginath In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Computational Science and Engineering Georgia Institute of Technology August 2014 Copyright © 2014 by Srikanth B. Yoginath VIRTUAL TIME-AWARE VIRTUAL MACHINE SYSTEMS Approved by: Dr. Kalyan S. Perumalla, Advisor Dr. Umakishore Ramachandran School of Computational Science and School of Computer Science Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Richard S. Fujimoto, Advisor Dr. George F. Riley School of Computational Science and School of Electrical and Computer Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. David A. Bader School of Computational Science and Engineering Georgia Institute of Technology Date Approved: July 1, 2014 ACKNOWLEDGEMENTS First and foremost, I am extremely grateful to have Dr. Kalyan Perumalla as my advisor at Oak Ridge National Laboratory (ORNL) and this thesis would not have been possible without his guidance and support. I am highly impressed with his expertise, enthusiasm and his ability to quickly glean the core of any given research problem. Under his supervision, I have been exposed to wide range of very interesting research projects and have learned a great deal by participating in them. I feel extremely fortunate and blessed to have had an opportunity to work as his research student. I am also extremely grateful to Dr. Richard Fujimoto, for being my advisor at Georgia Tech. I am honored to work as his student and would like to express my deepest gratitude for his support throughout my PhD endeavor. I would also like to thank Dr. David Bader, Dr. George Riley and Dr. Umakishore Ramachandran for serving as my thesis committee members, and for their insightful comments. I am extremely grateful to ORNL for providing me with an opportunity and the necessary financial support to pursue my PhD. At ORNL, I would like to thank Computational Sciences and Engineering Division directors Dr. Brian Worley and Dr. Shaun Gleason, and the Modeling and Simulation Group leaders Mr. David Hetrick and Dr. Robert Morris for their continuous encouragement and support. I would also like to thank Ms. Carolyn Ward at ORNL education assistance for making the logistic work related to my PhD effortless. I am also grateful for the timely funding of our research projects from Army Research Laboratory (ARL). I would like to thank Dr. Raju Namburu and Dr. Brian Henz from ARL for their support. iii At Georgia Tech, I would like to thank CSE graduate program advisors Mr. Michael Terrell and Ms. Haley Mimi, who have been extremely helpful and supportive. I would also like to thank Ms. Holly Rush for helping me make necessary arrangements for my dissertation defense. I very much appreciate Ms. Lometa Mitchell and Ms. Phinisee Della for their help. Finally, I would like to express my sincere gratitude to my wife, kids, parents and brothers for their continuous loving support throughout my PhD pursuit. Without their support and encouragement this work would not have been possible. iv TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................ iii TABLE OF CONTENTS ................................................................................................. v LIST OF TABLES .......................................................................................................... xii LIST OF FIGURES ....................................................................................................... xiii LIST OF ABBREVIATIONS ..................................................................................... xviii SUMMARY ..................................................................................................................... xx Chapter 1: INTRODUCTION ......................................................................................... 1 1.1 Virtual Machine (VM) ............................................................................................ 1 1.1.1 Virtual Machines History ................................................................................... 2 1.1.2 Virtualization of the X86 Architecture .............................................................. 4 1.1.3 Current Trends in Virtualization Technology .................................................... 5 1.1.4 The Xen Hypervisor ........................................................................................... 7 1.2 Virtual Time Systems (VTS) .................................................................................. 8 1.2.1 Background ........................................................................................................ 8 1.2.2 Parallel Discrete Event Simulation (PDES) ..................................................... 11 1.2.3 PDES Models ................................................................................................... 14 1.3 Problem Statement and Research Challenges .................................................... 17 1.3.1 VM within VTS ............................................................................................... 17 1.3.2 VTS over VMs ................................................................................................. 18 1.4 Research Contributions ........................................................................................ 20 v 1.4.1 VM within VTS ............................................................................................... 20 1.4.2 VTS over VM .................................................................................................. 24 1.5 Thesis Organization .............................................................................................. 26 Chapter 2: VM WITHIN VTS: CONCEPTS, DESIGN AND PROTOTYPE .......... 28 2.1 Network Simulation/Emulation Overview ......................................................... 28 2.1.1 Background ...................................................................................................... 28 2.1.2 VM based Network Modeling ......................................................................... 30 2.1.3 VM-based Network Emulators ........................................................................ 31 2.1.4 VM-based Network Simulators ....................................................................... 32 2.2 NetWarp Simulator .............................................................................................. 34 2.2.1 NetWarp Goals ................................................................................................. 34 2.2.2 NetWarp Architecture ...................................................................................... 34 2.2.3 NetWarp Core Conceptual Issues .................................................................... 36 2.2.4 NetWarp Prototyping Approach ...................................................................... 41 2.3 Prototyping Virtual Time-ordered VM Execution ............................................ 41 2.3.1 Xen Scheduler .................................................................................................. 41 2.3.2 NetWarp Scheduler for Xen (NSX) Data-structures ........................................ 42 2.3.3 Virtual Times of NetWarp ............................................................................... 48 2.3.4 Virtual Time Accounting ................................................................................. 48 2.3.5 Idle Time Accounting ...................................................................................... 49 2.3.6 Global Virtual Time ......................................................................................... 51 2.3.7 Modifying VM Time Slice Granularity ........................................................... 52 2.3.8 Virtual Time-ordered Execution ...................................................................... 52 vi 2.4 Prototyping Virtual-time Ordered Network Control ........................................ 53 2.4.1 Virtual Network in Xen ................................................................................... 53 2.4.2 Trapping Transiting Packets ............................................................................ 54 2.4.3 Enforcing Realistic Network Characteristics ................................................... 55 2.5 Prototype Evaluation ............................................................................................ 57 2.5.1 Benchmark Scenario ........................................................................................ 57 2.5.2 Hardware and Software .................................................................................... 59 2.5.3 Virtual Time-ordered VM Execution Test Results .......................................... 60 2.5.4 Virtual Time-ordered Network Control Results .............................................. 66 2.6 Summary ................................................................................................................ 68 Chapter 3: VM WITHIN VTS: SCALING STUDY .................................................... 70 3.1 Staggering of Virtual Time .................................................................................. 70 3.1.1 Virtual Time Evolution .................................................................................... 70 3.1.2 Virtual