&gt; But sure, you need a debugger. So you use one. I&#x27;m not sure why the author seems to think that&#x27;s so hard.<p>The author wrote and continues to contribute to DTrace, which is an incredibly advanced facility for debugging and root causing problems. GDB (for example) doesn&#x27;t help you solve performance problems or root-cause them, because now your performance problem has become ptrace (or whatever tracing facility GDB uses on that system).<p>The point he was making is that there are problems with porting DTrace to a unikernel (it violates the whole &quot;let&#x27;s remove everything&quot; principle, and you couldn&#x27;t practically modify what DTrace probes you&#x27;re using at runtime becuase the only process is your misbehaving app -- good luck getting it to enable the probes you&#x27;d like to enable).