[Updated Oct. 17] — Additional real-time technology will be incorporated into the mainline Linux kernel starting with version 2.6.18, TimeSys reports. The real-time support, which previously had to be installed as kernel patches, was developed in part by TimeSys senior open source developer Thomas Gleixner (pictured), the… company says.

Gleixner was the main author of Linux's hrtimer (high-resolution timer) subsystem, and has been a major contributor to Ingo Molnar's real-time preemption patch. The changelog for the 2.6.18 kernel reflects the addition of 136 patches authored by Gleixner, along with 143 from Molnar, who works for Red Hat.

The 2.6.18 release includes real-time technology that will save individual kernel developers from having to maintain separate real-time kernel trees, according to TimeSys. Additionally, embedded Linux developers or normal desktop users wishing to build kernels capable of achieving millisecond-level real-time responsiveness will no longer have to apply patches.

Gleixner summarizes the additions as follows:

• Priority Inheritance — support for user space futexes. “The PI technology is the same as it is used in the realtime preemption patch for Priority Inheritance of the in kernel concurrency controls.”
• Generic Interrupt layer enhancements, “which are necessary to provide the threaded interrupt handlers support in the realtime preemption patch.”

Gleixner stated, “I am pleased that we can simplify development for real-time embedded devices by bringing this technology into the mainline kernel.”

According to TimeSys, forthcoming Linux kernel releases are likely to offer additional real-time features that are currently only available as kernel patches. The company notes that these additional real-time kernel patches are already available through its LinuxLink suite of subscription-based online services for embedded Linux developers.

TimeSys CEO Larry Weidman stated, “The inclusion of real-time capabilities in the kernel validates the work of TimeSys in this space. Our customers that require real-time capabilities can be confident that they are on a path that has a clear future.”

Weidman adds, “By making real-time extensions available to all LinuxLink customers, we hope to make a supported real-time solution affordable to a wider audience.”

TimeSys has long taken a keen interest in real-time Linux. Before adopting a service-based business model, the company positioned its Linux distributions as the only “single-kernel real-time” Linux. MontaVista has also been an active developer and strong advocate of real-time Linux capabilities, as have FSMLabs, LynuxWorks, Red Hat, and others.

 
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