[lttng-dev] introduction & usage of LTTNG in machinekit

[Michel Dagenais]

> I am involved in machinekit.io, a portable realtime application for motion control
> machinekit runs on several kernels - starting from vanilla (no time
> guarantees), RT-PREEMPT, Xenomai, and RTAI; on x86, amd64 and ARM platforms.

I am actually using LinuxCNC on a small CNC mill and would love to get that running directly on PREEMPT-RT instead of Xenomai (modified Sieg SX3 mill, cncfusion conversion kit, servo motors on X, Y and Z axis, mesa FPGA and H bridge boards for control).

> As some of the processing is highly time sensitive, I'm looking into
> integrating LTTNG into the machinekit build so we have options beyond
> logging and timestamping manually. For instance, currently some
> transcendental math functions on ARM overrun the time budget.
> 
> I've started integrating the build support and am running into my first
> problems. So, that's the context of my following questions - thanks in
> advance for guiding me through any blunders.

This is an excellent application for LTTng. My group has been looking for good use cases of real-time applications. We have a significant expertise with Linux for real-time and PREEMPT-RT. We could easily help you with the machinekit tracing: kernel and user-space instrumentation, specific views and analysis for this application...