liblttng-ust-ctl4 2.10.1-1 (armhf binary) in ubuntu bionic

 The userspace tracer is designed to provide detailed information about
 userspace activity. Like the kernel tracer, performance is the main goal.
 Tracing does not require system calls or traps. UST instrumentation points may
 be added in any userspace code including signal handlers and libraries.
 .
 This package contains a library to control tracing in other processes. Used by
 lttng-tools.