New Linux 5.14 Tracer To Help With Measuring Operating System Noise

The tracing subsystem within the Linux kernel is seeing some exciting improvements with Linux 5.14 to help with low-latency analysis and also measuring operating system noise.

Linux 5.14 brings a new "osnoise" tracer for measuring noise attributed to the operating system and hardware when it comes to isolated applications. The OSNoise tracer keeps track of noise by monitoring entry points for NMIs / IRQs / SoftIRQs / threads in determining if the noise is coming from the OS or rather than hardware. There are also tracepoints setup for helping to further debug sources of noise.

In addition, the tracing work for Linux 5.14 brings "hwlat" improvements for that hardware latency debugging. The big change there is now allowing hwlat to run on multiple CPUs in parallel rather than its prior limitation of running on a single CPU at a time.

More details on the OSNoise tracer via this documentation. The list of other tracing subsystem updates for this kernel can be found via this Git merge.