runqlat and runqslower - eBPF command line tools
In this blog post we will look at runqlat and runqslower commands. They are available in both BCC and bpftrace tool collections. One of the core functions of Linux operating system is to schedule processes across available CPUs. When service gets a request, Linux typically will need to schedule the process, processing that request to run on one of CPUs. This might be very quick process if idle CPU is available or it can take significant time, if all CPUs are currently busy running different processes.