A new generation of real-time systems in the JET tokamak

JET EFDA Contributors

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Recently a new recipe for developing and deploying real-time systems has become increasingly adopted in the JET tokamak. Powered by the advent of x86 multi-core technology and the reliability of the JET’s well established Real-Time DataNetwork (RTDN) to handle all real-time I/O, an official Linux vanilla kernel has been demonstrated to be able to provide real-time performance to user-space applications that are required to meet stringent timing constraints. In particular, a careful rearrangement of the Interrupt ReQuests’ (IRQs) affinities together with the kernel’s CPU isolation mechanism allows to obtain either soft or hard real-time behavior depending on the synchronization mechanism adopted. Finally, the Multithreaded Application Real-Time executor (MARTe) framework is used for building applications particularly optimised for exploring multi-core architectures. In the past year, four new systems based on this philosophy have been installed and are now part ofthe JET’s routine operation. The focus of the present work is on the configuration and interconnection of the ingredients that enable these new systems’ real-time capability and on the impact that JET’s distributed real-time architecture has on system engineering requirements, such as algorithm testing and plant commissioning. Details are given about the common real-time configuration and development path of these systems, followed by a brief description of each system together with results regarding their real-time performance. A cycle time jitter analysis of a user-space MARTe based application synchronising over a network is also presented. The goal is to compare its deterministic performance while running on a vanilla and on a Messaging Real time Grid (MRG) Linux kernel.
Original languageEnglish
Title of host publication2012 18th IEEE-NPSS Real Time Conference
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Pages1-9
Number of pages9
ISBN (Electronic)978-1-4673-1084-0
ISBN (Print)978-1-4673-1082-6
DOIs
Publication statusPublished - 24 Jan 2013
Event18th Real-Time Conference 2012 - Berkeley, United States
Duration: 11 Jun 201215 Jun 2012
Conference number: 18
http://rt2012.lbl.gov/

Conference

Conference18th Real-Time Conference 2012
Abbreviated titleRT2012
Country/TerritoryUnited States
CityBerkeley
Period11/06/1215/06/12
Internet address

Keywords

  • fusion reactor safety
  • interrupts
  • Linux
  • multiprocessing systems
  • multi-threading
  • operating system kernels
  • parallel architectures
  • plasma toroidal confinement
  • real-time systems
  • reliability
  • synchronisation
  • timing jitter
  • Tokamak devices
  • JET tokamak
  • x86 multicore technology
  • JET reliability
  • real-time data network
  • real-time I/O system
  • Linux vanilla kernel
  • interrupt request affinities
  • CPU isolation mechanism
  • hard real-time behavior
  • soft real-time behavior
  • synchronization mechanism
  • multithreaded application real-time executor framework
  • multicore architectures
  • real-time capability
  • JET distributed real-time architecture
  • real-time configuration
  • messaging real time grid Linux kernel
  • user-space MARTe based application
  • cycle time jitter analysis
  • Real-time systems
  • Kernel
  • Jitter
  • Plasmas
  • Switches
  • Stress
  • Real-Time
  • Nuclear Fusion

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