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Real-time kernel upgraded

Jun 12, 2009 — by Eric Brown — from the LinuxDevices Archive — 2 views

The Open Source Automation Development Lab (OSADL) released a “latest stable” real-time Linux kernel based on Linux 2.6.29, and has merged its threaded interrupt real-time code into the Linux 2.6.30 mainline. The OSADL also announced its Real Time Linux Workshop (RTLWS11), to be held in Dresden, Germany, on Sep. 28-30.

The OSADL recently expanded to over 30 members, with the acceptance of Intel, Protonic, Sercos, and Sysgo. The industry group aims to standardize and promote Linux support for automation technologies. Earlier this year, the group integrated the Real-Time Linux Foundation (RTLF) within the OSADL, and then released a “latest stable” Linux 2.6.26 real-time kernel with PREEMPT_RT patches stabilized with the mainline Linux 2.6.26 kernel. The release was said to achieve latency as low as 39 microseconds.

Now, the OSADL has released a “latest stable” release of real-time Linux, deemed ready for production. Meanwhile, with the release of Linux mainline kernel 2.6.30 this week, threaded interrupts that previously were only available in the -rt tree have been folded into the mainline kernel. The -rt tree of 2.6.29 was designated “latest stable” on the same day as 2.6.30 was released, reports the OSADL's Carsten Emde.

“We are only one release number behind!” Emde enthuses in his blog on the release. “And the distance between vanilla and -rt will become even closer in the near future, until both are released the same day — the day when the CONFIG_PREEMPT_RT configuration item will appear in an unpatched vanilla kernel.”

Thomas Gleixner

The PREEMPT_RT patches provide guarantees for hard timing deadlines, as required by many mission critical applications in industries like telecom, military, healthcare, music recording, and financial trading. Sometimes referred to as the “RT Preempt” patch, PREEMPT_RT was originally developed by Ingo Molnar and Thomas Gleixner (pictured). It represents the upstream version of the real-time patches integrated by MontaVista, Red Hat, Novell, and others into the “real-time” versions of their commercial Linux offerings

Real Time Linux Workshop call to papers extended to Monday

The OSADL has extended its paper submission deadline for September's Eleventh Real Time Linux Workshop (RTLWS11) until this Monday, June 15. Meanwhile, a number of speakers have already been confirmed for the Dresden event (see below). In the two days before the workshop, an RT Kernel summit will be held at the same Technische Universitat Dresden venue, and most participants will be available during RTLWS11 for two additional program sections:

  • Real Time Kernel Developers Track — Invited lectures on special aspects of Linux and real time such as real-time in vanilla Linux, kernel tracing, preemptive RCU, PI mutexes, latency measurements, threaded IRQs, caching implications, and virtualization
  • Meet Real Time Kernel Developers — Open panel discussion on Linux and real-time (i.e., everything you always wanted to know about Linux real-time but were afraid to ask.)

Paul McKenney

Kernel developers and real time specialists confirmed to participate at RTLWS11 include:

  • Jonathan Corbet
  • Thomas Gleixner (pictured above)
  • Nicholas Mc Guire
  • Darren Hart
  • Paul McKenney (pictured)
  • Steven Rostedt
  • Peter Zijlstra


The Eleventh Real Time Linux Workshop (RTLWS11) will be held in Dresden, Germany, at Technische Universitat Dresden (Dresden Technical University) on Sep. 28-30. The submission form for paper authors may be found here, but must be used no later than Monday. Registration for general participation at the workshop may be found here.

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