Tracing tools on Linux has always been rather poor. While other systems have some really nifty tools (for example, dtrace on Solaris, Mac and FreeBSD). Sure, there's things like SystemTap, but feel nowhere near as nice and complete as dtrace. Kind of sad since the Linux kernel actually has quite a fair amount of instrumentation in it - it's just really hard to use.

ktap looks like an interesting approach using a modified Lua bytecode interpreter to allow writing probe scripts. Hopefully this avoids the problems of the GCC based toolchain used by SystemTap.