When used with multi-core processors with two or more cores, one core is isolated from the rest of the software flow and is used exclusively (asymmetrically) with specialized real-time software.
The advantage of this architecture is strict isolation of real-time tasks – for example a control algorithm – from the rest of the system. emlix has developed real-time applications for the F&S armStoneA9 single board computer and efusA9 computer on module, using one of four cores exclusively to drive a control mechanism with 10 µsec cycle time. With average system usage, the jitter is below 1 µsec and stays below 5 µsec under full benchmark load of all CPU cores and the internal memory buses.
The real-time software was programmed using C with a few lines of Assembler code. The control mechanism uses GPIOs. All interfaces and processes irrelevant to real-time, stay on the Linux controlled cores. This enables simultaneous and unrestricted use of USB, Ethernet, PCIe, control and visualization of graphics for user interfaces and other interfaces.
This add-on offers the user an alternative for the development and long-term service of real-time systems based on embedded Linux besides Preempt-RT and Xenomai/Adeos.