Dear Samba Team, I am experiencing a Samba4 AD bug that consumes 100% cpu usage (one thread). The strace on the problematic PID reports a whole loop of fcntl calls on FD 13, which points to "dc=domain,dc=local.ldb" file. I also have a core dump which I could send to you if you need it to find the issue. I must also note that the issue persists even if I restart the samba, so currently my Samba 4 DC setup consumes 100% on two machines.
A gdb 'bt full' on the core dump or process would have been useful, but I'm hoping that since 2014 we have fixed that, particularly with the performance improvements we have made for Samba 4.5.0rc1. Otherwise, feel free to re-open and help us with info a 'flame graph' of the problem process: http://www.brendangregg.com/FlameGraphs/cpuflamegraphs.html (These tend to be the best debugging tool for this kind of thing).