RTEMS Use at SLAC

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RTEMS Use at SLAC
EPICS Collaboration Legnaro, Italy October 15-17,
2008
Ernest Williams
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RTEM-based IOCs

• Large number of IOCs running reliably for LCLS
  Accelerator
• 136 Coldfire-based embedded IOCs
• Mainly used for BPM and LLRF front-end processors
• 104 MVME6100 IOCs
• 33 MVME3100 IOCs
• Beamlines will also use some number RTEMS-based
  IOCs for Slow controls.

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RTEMS

• All production IOCs are running RTEMS version
  4.7.1 except for the IOCs responsible for
  Undulator motion controls which runs RTEMS
  version 4.9.0
• RTEMS distro used at SLAC is supported by Till
  Strauman from SSRL who works closely with LCLS on
  a number of projects.
• We have found the technical support provided by
  Till to be very responsive and reliable

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RTEMS Some new Features for 4.9.0

• Added NFS client developed at SLAC to the main
  distribution at OAR.
• Modifications to telnet for supporting
  epicsThreadCreate.
• High resolution timer when reading system clock.
• BSP support for the MVME3100
• New CEXP features
• new ELF/BFD replacement library (written from
  scratch). Eliminates the dependency on
  GPL-licensed third-party libs (which can still be
  usedif desired)

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RTEMS Some new Features for 4.9.0

• New CEXP features
• support for loading into multiple memory
  segments. This can be used on PPCto load text
  data into different areas -gt solves 32MB
  branch-limitproblem. no need to compile with
  -mlong flag
• changeable shell prompt
• can load modules with weak undefined symbols
• added special user variable 'ans' which holds the
  result of the last evaluated line (like matlab
  'ans' or bash '?')

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RTEMS RoadMap for SLAC

• New CEXP will be posted soon along with the
  SLAC-based distro of RTEMS.
• CEXP will be part of the RTEMS main distro at OAR
  in future releases.
• Continue to work closely with Eric Norum and
  others in the community to provide One Stop
  Shopping for an EPICS-ready RTEMs distribution
• Improve the distribution and packaging so that
  interested users can configure and run RTEMS at
  their site. Till is working to make all of the
  SLAC developed RTEMS add-ons use autoconf.
• Support for IOC health monitoring for RTEMS-based
  IOCs

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RTEMS and IOC Health
GOAL New module called iocAdmin which merges
work from vxStats into a generic framework for
platform independent IOC health monitoring.
Work done by Stephanie Allison
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devIocStats OSI-fied devVxStats/linuxStats from
SNS with added RTEMS hooks

• Provides IOC health PVs
• CPU load, Memory
• free FDs, suspended tasks, CA connections,
  CA PVs, IF input/output errors
• MBUF cluster information
• Strings up time, startup, cwd, IOC engineer,
  location, logname, hostname, EPICS version, BSP,
  Kernel, boot line

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• OSI implementation similar to Martys OSI devLib
• src/devIocStats general code
• src/os/RTEMS, vxWorks, default/devIocStatsOSD.
  OS-specific hooks
• Similar in concept to devIocStats from Phil
  Sorensen at CHESS.
• Does not have the features that SLS added to
  their own devVxStats.
• Till Straumann did RTEMS hooks (turns out to be
  very similar to the CHESS implementation) and got
  vxStats cpuBurn logic working for RTEMS.
  However, we decided to use Phils CPU load
  calculation instead which is based on IDLE task
  usage.
• Can use the same DB for both soft and hard IOCs
  some records will have unimplemented values,
  depending on OS.
• Will be available from soft support soon.

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Prototype Displays RTEMS IOC
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Prototype Displays Linux IOC
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Conclusion

• At SLAC We plan to support iocAdmin
• vxWorks 5.4.2 and up
• WindRiver continues to change the network stack.
  ?
• rtems 4.7.1 and rtems 4.9.x
• Work closely with EPICS community for future
  enhancements and features.
• After our operational experience with RTEMS at
  the LCLS, I can now seriously recommend RTEMS as
  an alternative or complement to using vxWorks for
  new sites.

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Acknowledgements

• Till Strauman
• Stephanie Allison