see https://code.google.com/p/gperftools/issues/detail?id=335 where gperftool maintainers admit this is probably needed and the thread at https://groups.google.com/forum/#!topic/google-perftools/gEpE7_AdibI . This is a regression in gperftools as it wasn't needed in the near past. But many, many years ago it was needed when I was profiling mysqld. I added the call to ProfilerRegisterThread to to handleIncomingMsg. In this case I compiled the server with --user-cpu-profiler, called _cpuProfilerStart, ran a workload, called _cpuProfilerStop