Summary
Nobody can complain that Linux lacks options for profiling and tracing. This chapter has given you an overview of some of the most common ones.
When faced with a system that is not performing as well as you would like, start with top and try to identify the problem. If it proves to be a single application, then you can use perf record/report to profile it. Bear in mind that you will have to configure the kernel to enable perf and you will need debug symbols for both the binaries and kernel. If the problem is not so well localized, use perf or ply to get a system-wide view.
Ftrace comes into its own when you have specific questions about the behavior of the kernel. The function and function_graph tracers provide a detailed view of the relationship and sequence of function calls. The event tracers allow you to extract more information about functions, including the parameters and return values.
LTTng performs a similar role, making use of the event trace mechanism...
