Handle fork in target application (#191)

* Always print PID in log messages

* omnitrace-dl updates

- omnitrace_preload does not call omnitrace_init or omnitrace_init_tooling
- omnitrace_preload will call omnitrace_set_mpi if OMNITRACE_USE_MPI
  or OMNITRACE_USE_MPIP in the env is true but not call it otherwise
  because doing so either overrides OMNITRACE_USE_PID (when true) or
  disable mpip from initialization (when false) and the MPI
  init can be caught later and override OMNITRACE_USE_PID

* config updates

- set_setting_value sets user update type
- remove volatile from get_settings_configured
- don't override settings::default_process_suffix
- don't kill process in omnitrace_exit_action
- set_state ignores updating state if >= State::Finalized

* Handle state > State::Finalized

* fork gotcha updates

- unsets LD_PRELOAD
- sets OMNITRACE_ROOT_PROCESS
- sets OMNITRACE_CHILD_PROCESS

* libomnitrace library.cpp updates

- basic_bundle for fini metrics
- handle finalization from child process

* sampling updates

- sampling::shutdown handles when child process

* Add example and test using fork

* Update run-ci script to support not submitting

* Tweak test envs

* Update build flags when codecov enabled

* remove unnecessary includes of sampling header

* Replace mpi copy/fini static lambda with free-funcs

* Update codecov job

* Fix OMPT segfaults after finalization

* Miscellaneous updates after rebase

* fixes for causal profiling

* revert some run-ci.sh changes

* Disable storing env in sampling::shutdown

* formatting fix

* Update timemory submodule

- fixed occasional synchronization issues with allocator offloading
- exclude protozero:: from internal samples

* improve root/child process detection

- avoid omnitrace_finalize in MPI when child process
- revert some testing tweaks

source/lib/omnitrace/library/sampling.cpp

@@ -333,7 +333,7 @@ start_duration_thread()
                 if(!_lk.owns_lock()) _lk.lock();
                 get_duration_cv().wait_until(_lk, _end);
                 auto _premature = (std::chrono::steady_clock::now() < _end);
-                auto _finalized = (get_state() == State::Finalized);
+                auto _finalized = (get_state() >= State::Finalized);
                 if(_premature && !_finalized)
                 {
                     // protect against spurious wakeups
@@ -480,6 +480,7 @@ configure(bool _setup, int64_t _tid)
                                 "causal profiling is enabled");
 
     OMNITRACE_SCOPED_SAMPLING_ON_CHILD_THREADS(false);
+    OMNITRACE_SCOPED_THREAD_STATE(ThreadState::Internal);
 
     auto&& _cpu_tids  = get_sampling_cpu_tids();
     auto&& _real_tids = get_sampling_real_tids();
@@ -673,6 +674,13 @@ setup()
 std::set<int>
 shutdown()
 {
+    if(is_child_process())
+    {
+        for(auto& itr : sampler_instances::instances())
+            itr.release();
+        return std::set<int>{};
+    }
+
     auto _v = configure(false);
     if(utility::get_thread_index() == 0) stop_duration_thread();
     return _v;