LTTng (Linux Trace Toolkit Next Generation) is a tracer for Linux.
It is a kernel module accompanied by a toolchain (ltt-control) to control the tracing, as well as a trace viewing and analysis application (LTTV).
LTTng includes a set of kernel instrumentation points useful for debugging a wide range of bugs, that are otherwise extremely challenging.
These include, for example, performance problems on parallel systems and on real-time systems.
LTTng is designed for minimal performance impact and has a near zero impact when not tracing. LTTng has at least basic support for all Linux architectures.