Miniconf-UK/2014/debugging profiling

In this session I aim to go through some nice tricks that I have picked up whilst debugging and profiling workloads. Most of these have been learnt by banging my head against the desk, and would have saved me time had I known about them :-).

A lot of the material will be introductory, but I hope parts of it will be interesting for everyone.

I aim to:

• Introduce gdb.
  • multi-threaded workloads.
  • conditional breakpoints.
  • Hooking it up to valgrind.
• Introduce ftrace
  • Profile the kernel with "echo" and "cat". :-)
  • Using function graphs to explore how the kernel works.
• Introduce Linux perf
  • A quick primer on how PMU sampling works.
  • Some basic tracing ("perf top", "perf record")
  • Capturing other performance events.
  • Intro to kprobes.
  • Intro uprobes. [provisional]
  • "perf script" to perform analysis.
• Introduce LTTNG [provisional]
  • Hook it up to perf [provisional]
• The importance of debugging information
  • Debugging a package with/without debugging info.
  • Profiling a package with/without debugging info.