While trying to upgrade Erlang in the rumprun-packages to the latest Erlang 19.0 release I am noticing a very strange behavior. Surprisingly the Erlang application main is never called (quick test via gdb), while the vm is running indefinitely occupying 100% of a core doing something. I spent a couple of minutes interrupting the run within gdb (a couple of times via SIGINT and then continuing) but it was not very useful. I am not too sure whether it's something to do with the build (probably unlikely), which I plan to rebuild from scratch tonight anyways. Having said that it'll be great to have a tracing/debugging as to understand where the kernel is spending all its time and why. Is there anything similar to lttng or alternate means to get detailed logging of where the kernel is spending its time?
Surprisingly the same build of rumprun works flawlessly with earlier release of Erlang, which makes me wonder if this has something to do with the result of the baking process? Note that the command to run the kernel within qemu (with and without kvm) remains same across runs (memory and stuff). -Neeraj
