int ompi_mpi_finalize(void)
{
int ret;
static int32_t finalize_has_already_started = 0;
opal_list_item_t *item;
struct timeval ompistart, ompistop;
ompi_rte_collective_t *coll;
ompi_proc_t** procs;
size_t nprocs;
/* Be a bit social if an erroneous program calls MPI_FINALIZE in
two different threads, otherwise we may deadlock in
ompi_comm_free() (or run into other nasty lions, tigers, or
bears) */
if (! opal_atomic_cmpset_32(&finalize_has_already_started, 0, 1)) {
/* Note that if we're already finalized, we cannot raise an
MPI exception. The best that we can do is write something
to stderr. */
char hostname[MAXHOSTNAMELEN];
pid_t pid = getpid();
gethostname(hostname, sizeof(hostname));
opal_show_help("help-mpi-runtime.txt",
"mpi_finalize:invoked_multiple_times",
true, hostname, pid);
return MPI_ERR_OTHER;
}
ompi_mpiext_fini();
/* Per MPI-2:4.8, we have to free MPI_COMM_SELF before doing
anything else in MPI_FINALIZE (to include setting up such that
MPI_FINALIZED will return true). */
if (NULL != ompi_mpi_comm_self.comm.c_keyhash) {
ompi_attr_delete_all(COMM_ATTR, &ompi_mpi_comm_self,
ompi_mpi_comm_self.comm.c_keyhash);
OBJ_RELEASE(ompi_mpi_comm_self.comm.c_keyhash);
ompi_mpi_comm_self.comm.c_keyhash = NULL;
}
/* Proceed with MPI_FINALIZE */
ompi_mpi_finalized = true;
/* As finalize is the last legal MPI call, we are allowed to force the release
* of the user buffer used for bsend, before going anywhere further.
*/
(void)mca_pml_base_bsend_detach(NULL, NULL);
nprocs = 0;
procs = ompi_proc_all(&nprocs);
MCA_PML_CALL(del_procs(procs, nprocs));
free(procs);
#if OMPI_ENABLE_PROGRESS_THREADS == 0
opal_progress_set_event_flag(OPAL_EVLOOP_ONCE | OPAL_EVLOOP_NONBLOCK);
#endif
/* Redo ORTE calling opal_progress_event_users_increment() during
MPI lifetime, to get better latency when not using TCP */
opal_progress_event_users_increment();
/* check to see if we want timing information */
if (ompi_enable_timing != 0 && 0 == OMPI_PROC_MY_NAME->vpid) {
gettimeofday(&ompistart, NULL);
}
/* NOTE: MPI-2.1 requires that MPI_FINALIZE is "collective" across
*all* connected processes. This only means that all processes
have to call it. It does *not* mean that all connected
processes need to synchronize (either directly or indirectly).
For example, it is quite easy to construct complicated
scenarios where one job is "connected" to another job via
transitivity, but have no direct knowledge of each other.
Consider the following case: job A spawns job B, and job B
later spawns job C. A "connectedness" graph looks something
like this:
A <--> B <--> C
So what are we *supposed* to do in this case? If job A is
still connected to B when it calls FINALIZE, should it block
until jobs B and C also call FINALIZE?
After lengthy discussions many times over the course of this
project, the issue was finally decided at the Louisville Feb
2009 meeting: no.
Rationale:
- "Collective" does not mean synchronizing. It only means that
every process call it. Hence, in this scenario, every
process in A, B, and C must call FINALIZE.
- KEY POINT: if A calls FINALIZE, then it is erroneous for B or
C to try to communicate with A again.
- Hence, OMPI is *correct* to only effect a barrier across each
jobs' MPI_COMM_WORLD before exiting. Specifically, if A
calls FINALIZE long before B or C, it's *correct* if A exits
at any time (and doesn't notify B or C that it is exiting).
- Arguably, if B or C do try to communicate with the now-gone
A, OMPI should try to print a nice error ("you tried to
communicate with a job that is already gone...") instead of
segv or other Badness. However, that is an *extremely*
difficult problem -- sure, it's easy for A to tell B that it
is finalizing, but how can A tell C? A doesn't even know
about C. You'd need to construct a "connected" graph in a
distributed fashion, which is fraught with race conditions,
etc.
Hence, our conclusion is: OMPI is *correct* in its current
behavior (of only doing a barrier across its own COMM_WORLD)
before exiting. Any problems that occur are as a result of
erroneous MPI applications. We *could* tighten up the erroneous
cases and ensure that we print nice error messages / don't
crash, but that is such a difficult problem that we decided we
have many other, much higher priority issues to handle that deal
with non-erroneous cases. */
/* wait for everyone to reach this point
This is a grpcomm barrier instead of an MPI barrier because an
MPI barrier doesn't ensure that all messages have been transmitted
before exiting, so the possibility of a stranded message exists.
*/
coll = OBJ_NEW(ompi_rte_collective_t);
coll->id = ompi_process_info.peer_fini_barrier;
coll->active = true;
if (OMPI_SUCCESS != (ret = ompi_rte_barrier(coll))) {
OMPI_ERROR_LOG(ret);
return ret;
}
/* wait for barrier to complete */
OMPI_LAZY_WAIT_FOR_COMPLETION(coll->active);
OBJ_RELEASE(coll);
/* check for timing request - get stop time and report elapsed
time if so */
if (ompi_enable_timing && 0 == OMPI_PROC_MY_NAME->vpid) {
gettimeofday(&ompistop, NULL);
opal_output(0, "ompi_mpi_finalize[%ld]: time to execute barrier %ld usec",
(long)OMPI_PROC_MY_NAME->vpid,
(long int)((ompistop.tv_sec - ompistart.tv_sec)*1000000 +
(ompistop.tv_usec - ompistart.tv_usec)));
}
/*
* Shutdown the Checkpoint/Restart Mech.
*/
if (OMPI_SUCCESS != (ret = ompi_cr_finalize())) {
OMPI_ERROR_LOG(ret);
}
/* Shut down any bindings-specific issues: C++, F77, F90 */
/* Remove all memory associated by MPI_REGISTER_DATAREP (per
MPI-2:9.5.3, there is no way for an MPI application to
*un*register datareps, but we don't want the OMPI layer causing
memory leaks). */
while (NULL != (item = opal_list_remove_first(&ompi_registered_datareps))) {
OBJ_RELEASE(item);
}
OBJ_DESTRUCT(&ompi_registered_datareps);
/* Remove all F90 types from the hash tables. As the OBJ_DESTRUCT will
* call a special destructor able to release predefined types, we can
* simply call the OBJ_DESTRUCT on the hash table and all memory will
* be correctly released.
*/
OBJ_DESTRUCT( &ompi_mpi_f90_integer_hashtable );
OBJ_DESTRUCT( &ompi_mpi_f90_real_hashtable );
OBJ_DESTRUCT( &ompi_mpi_f90_complex_hashtable );
/* Free communication objects */
/* free file resources */
if (OMPI_SUCCESS != (ret = ompi_file_finalize())) {
return ret;
}
/* free window resources */
if (OMPI_SUCCESS != (ret = ompi_win_finalize())) {
return ret;
}
if (OMPI_SUCCESS != (ret = ompi_osc_base_finalize())) {
return ret;
}
/* free pml resource */
if(OMPI_SUCCESS != (ret = mca_pml_base_finalize())) {
return ret;
}
/* free communicator resources */
if (OMPI_SUCCESS != (ret = ompi_comm_finalize())) {
return ret;
}
/* free requests */
if (OMPI_SUCCESS != (ret = ompi_request_finalize())) {
return ret;
}
if (OMPI_SUCCESS != (ret = ompi_message_finalize())) {
return ret;
}
/* If requested, print out a list of memory allocated by ALLOC_MEM
but not freed by FREE_MEM */
if (0 != ompi_debug_show_mpi_alloc_mem_leaks) {
mca_mpool_base_tree_print();
}
/* Now that all MPI objects dealing with communications are gone,
shut down MCA types having to do with communications */
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_pml_base_framework) ) ) {
OMPI_ERROR_LOG(ret);
return ret;
}
/* shut down buffered send code */
mca_pml_base_bsend_fini();
#if OPAL_ENABLE_FT_CR == 1
/*
* Shutdown the CRCP Framework, must happen after PML shutdown
*/
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_crcp_base_framework) ) ) {
OMPI_ERROR_LOG(ret);
return ret;
}
#endif
/* Free secondary resources */
/* free attr resources */
if (OMPI_SUCCESS != (ret = ompi_attr_finalize())) {
return ret;
}
/* free group resources */
if (OMPI_SUCCESS != (ret = ompi_group_finalize())) {
return ret;
}
/* free proc resources */
if ( OMPI_SUCCESS != (ret = ompi_proc_finalize())) {
return ret;
}
/* finalize the pubsub functions */
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_pubsub_base_framework) ) ) {
return ret;
}
/* finalize the DPM framework */
if ( OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_dpm_base_framework))) {
return ret;
}
/* free internal error resources */
if (OMPI_SUCCESS != (ret = ompi_errcode_intern_finalize())) {
return ret;
}
/* free error code resources */
if (OMPI_SUCCESS != (ret = ompi_mpi_errcode_finalize())) {
return ret;
}
/* free errhandler resources */
if (OMPI_SUCCESS != (ret = ompi_errhandler_finalize())) {
return ret;
}
/* Free all other resources */
/* free op resources */
if (OMPI_SUCCESS != (ret = ompi_op_finalize())) {
return ret;
}
/* free ddt resources */
if (OMPI_SUCCESS != (ret = ompi_datatype_finalize())) {
return ret;
}
/* free info resources */
if (OMPI_SUCCESS != (ret = ompi_info_finalize())) {
return ret;
}
/* Close down MCA modules */
/* io is opened lazily, so it's only necessary to close it if it
was actually opened */
if (0 < ompi_io_base_framework.framework_refcnt) {
/* May have been "opened" multiple times. We want it closed now */
ompi_io_base_framework.framework_refcnt = 1;
if (OMPI_SUCCESS != mca_base_framework_close(&ompi_io_base_framework)) {
return ret;
}
}
(void) mca_base_framework_close(&ompi_topo_base_framework);
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_osc_base_framework))) {
return ret;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_coll_base_framework))) {
return ret;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_bml_base_framework))) {
return ret;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_mpool_base_framework))) {
return ret;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_rcache_base_framework))) {
return ret;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_allocator_base_framework))) {
return ret;
}
if (NULL != ompi_mpi_main_thread) {
OBJ_RELEASE(ompi_mpi_main_thread);
ompi_mpi_main_thread = NULL;
}
/* Leave the RTE */
if (OMPI_SUCCESS != (ret = ompi_rte_finalize())) {
return ret;
}
/* now close the rte framework */
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_rte_base_framework) ) ) {
OMPI_ERROR_LOG(ret);
return ret;
}
if (OPAL_SUCCESS != (ret = opal_finalize_util())) {
return ret;
}
/* All done */
return MPI_SUCCESS;
}
int ompi_mpi_finalize(void)
{
int ret = MPI_SUCCESS;
opal_list_item_t *item;
ompi_proc_t** procs;
size_t nprocs;
OPAL_TIMING_DECLARE(tm);
OPAL_TIMING_INIT_EXT(&tm, OPAL_TIMING_GET_TIME_OF_DAY);
/* Be a bit social if an erroneous program calls MPI_FINALIZE in
two different threads, otherwise we may deadlock in
ompi_comm_free() (or run into other nasty lions, tigers, or
bears).
This lock is held for the duration of ompi_mpi_init() and
ompi_mpi_finalize(). Hence, if we get it, then no other thread
is inside the critical section (and we don't have to check the
*_started bool variables). */
opal_mutex_lock(&ompi_mpi_bootstrap_mutex);
if (!ompi_mpi_initialized || ompi_mpi_finalized) {
/* Note that if we're not initialized or already finalized, we
cannot raise an MPI exception. The best that we can do is
write something to stderr. */
char hostname[MAXHOSTNAMELEN];
pid_t pid = getpid();
gethostname(hostname, sizeof(hostname));
if (ompi_mpi_initialized) {
opal_show_help("help-mpi-runtime.txt",
"mpi_finalize: not initialized",
true, hostname, pid);
} else if (ompi_mpi_finalized) {
opal_show_help("help-mpi-runtime.txt",
"mpi_finalize:invoked_multiple_times",
true, hostname, pid);
}
opal_mutex_unlock(&ompi_mpi_bootstrap_mutex);
return MPI_ERR_OTHER;
}
ompi_mpi_finalize_started = true;
ompi_mpiext_fini();
/* Per MPI-2:4.8, we have to free MPI_COMM_SELF before doing
anything else in MPI_FINALIZE (to include setting up such that
MPI_FINALIZED will return true). */
if (NULL != ompi_mpi_comm_self.comm.c_keyhash) {
ompi_attr_delete_all(COMM_ATTR, &ompi_mpi_comm_self,
ompi_mpi_comm_self.comm.c_keyhash);
OBJ_RELEASE(ompi_mpi_comm_self.comm.c_keyhash);
ompi_mpi_comm_self.comm.c_keyhash = NULL;
}
/* Proceed with MPI_FINALIZE */
ompi_mpi_finalized = true;
/* As finalize is the last legal MPI call, we are allowed to force the release
* of the user buffer used for bsend, before going anywhere further.
*/
(void)mca_pml_base_bsend_detach(NULL, NULL);
#if OPAL_ENABLE_PROGRESS_THREADS == 0
opal_progress_set_event_flag(OPAL_EVLOOP_ONCE | OPAL_EVLOOP_NONBLOCK);
#endif
/* Redo ORTE calling opal_progress_event_users_increment() during
MPI lifetime, to get better latency when not using TCP */
opal_progress_event_users_increment();
/* check to see if we want timing information */
OPAL_TIMING_MSTART((&tm,"time to execute finalize barrier"));
/* NOTE: MPI-2.1 requires that MPI_FINALIZE is "collective" across
*all* connected processes. This only means that all processes
have to call it. It does *not* mean that all connected
processes need to synchronize (either directly or indirectly).
For example, it is quite easy to construct complicated
scenarios where one job is "connected" to another job via
transitivity, but have no direct knowledge of each other.
Consider the following case: job A spawns job B, and job B
later spawns job C. A "connectedness" graph looks something
like this:
A <--> B <--> C
So what are we *supposed* to do in this case? If job A is
still connected to B when it calls FINALIZE, should it block
until jobs B and C also call FINALIZE?
After lengthy discussions many times over the course of this
project, the issue was finally decided at the Louisville Feb
2009 meeting: no.
Rationale:
- "Collective" does not mean synchronizing. It only means that
every process call it. Hence, in this scenario, every
process in A, B, and C must call FINALIZE.
- KEY POINT: if A calls FINALIZE, then it is erroneous for B or
C to try to communicate with A again.
- Hence, OMPI is *correct* to only effect a barrier across each
jobs' MPI_COMM_WORLD before exiting. Specifically, if A
calls FINALIZE long before B or C, it's *correct* if A exits
at any time (and doesn't notify B or C that it is exiting).
- Arguably, if B or C do try to communicate with the now-gone
A, OMPI should try to print a nice error ("you tried to
communicate with a job that is already gone...") instead of
segv or other Badness. However, that is an *extremely*
difficult problem -- sure, it's easy for A to tell B that it
is finalizing, but how can A tell C? A doesn't even know
about C. You'd need to construct a "connected" graph in a
distributed fashion, which is fraught with race conditions,
etc.
Hence, our conclusion is: OMPI is *correct* in its current
behavior (of only doing a barrier across its own COMM_WORLD)
before exiting. Any problems that occur are as a result of
erroneous MPI applications. We *could* tighten up the erroneous
cases and ensure that we print nice error messages / don't
crash, but that is such a difficult problem that we decided we
have many other, much higher priority issues to handle that deal
with non-erroneous cases. */
/* Wait for everyone to reach this point. This is a grpcomm
barrier instead of an MPI barrier for (at least) two reasons:
1. An MPI barrier doesn't ensure that all messages have been
transmitted before exiting (e.g., a BTL can lie and buffer a
message without actually injecting it to the network, and
therefore require further calls to that BTL's progress), so
the possibility of a stranded message exists.
2. If the MPI communication is using an unreliable transport,
there's a problem of knowing that everyone has *left* the
barrier. E.g., one proc can send its ACK to the barrier
message to a peer and then leave the barrier, but the ACK
can get lost and therefore the peer is left in the barrier.
Point #1 has been known for a long time; point #2 emerged after
we added the first unreliable BTL to Open MPI and fixed the
del_procs behavior around May of 2014 (see
https://svn.open-mpi.org/trac/ompi/ticket/4669#comment:4 for
more details). */
opal_pmix.fence(NULL, 0);
/* check for timing request - get stop time and report elapsed
time if so */
OPAL_TIMING_MSTOP(&tm);
OPAL_TIMING_DELTAS(ompi_enable_timing, &tm);
OPAL_TIMING_REPORT(ompi_enable_timing_ext, &tm);
OPAL_TIMING_RELEASE(&tm);
/*
* Shutdown the Checkpoint/Restart Mech.
*/
if (OMPI_SUCCESS != (ret = ompi_cr_finalize())) {
OMPI_ERROR_LOG(ret);
}
/* Shut down any bindings-specific issues: C++, F77, F90 */
/* Remove all memory associated by MPI_REGISTER_DATAREP (per
MPI-2:9.5.3, there is no way for an MPI application to
*un*register datareps, but we don't want the OMPI layer causing
memory leaks). */
while (NULL != (item = opal_list_remove_first(&ompi_registered_datareps))) {
OBJ_RELEASE(item);
}
OBJ_DESTRUCT(&ompi_registered_datareps);
/* Remove all F90 types from the hash tables. As the OBJ_DESTRUCT will
* call a special destructor able to release predefined types, we can
* simply call the OBJ_DESTRUCT on the hash table and all memory will
* be correctly released.
*/
OBJ_DESTRUCT( &ompi_mpi_f90_integer_hashtable );
OBJ_DESTRUCT( &ompi_mpi_f90_real_hashtable );
OBJ_DESTRUCT( &ompi_mpi_f90_complex_hashtable );
/* Free communication objects */
/* free file resources */
if (OMPI_SUCCESS != (ret = ompi_file_finalize())) {
goto done;
}
/* free window resources */
if (OMPI_SUCCESS != (ret = ompi_win_finalize())) {
goto done;
}
if (OMPI_SUCCESS != (ret = ompi_osc_base_finalize())) {
goto done;
}
/* free communicator resources. this MUST come before finalizing the PML
* as this will call into the pml */
if (OMPI_SUCCESS != (ret = ompi_comm_finalize())) {
goto done;
}
/* call del_procs on all allocated procs even though some may not be known
* to the pml layer. the pml layer is expected to be resilient and ignore
* any unknown procs. */
nprocs = 0;
procs = ompi_proc_get_allocated (&nprocs);
MCA_PML_CALL(del_procs(procs, nprocs));
free(procs);
/* free pml resource */
if(OMPI_SUCCESS != (ret = mca_pml_base_finalize())) {
goto done;
}
/* free requests */
if (OMPI_SUCCESS != (ret = ompi_request_finalize())) {
goto done;
}
if (OMPI_SUCCESS != (ret = ompi_message_finalize())) {
goto done;
}
/* If requested, print out a list of memory allocated by ALLOC_MEM
but not freed by FREE_MEM */
if (0 != ompi_debug_show_mpi_alloc_mem_leaks) {
mca_mpool_base_tree_print(ompi_debug_show_mpi_alloc_mem_leaks);
}
/* Now that all MPI objects dealing with communications are gone,
shut down MCA types having to do with communications */
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_pml_base_framework) ) ) {
OMPI_ERROR_LOG(ret);
goto done;
}
/* shut down buffered send code */
mca_pml_base_bsend_fini();
#if OPAL_ENABLE_FT_CR == 1
/*
* Shutdown the CRCP Framework, must happen after PML shutdown
*/
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_crcp_base_framework) ) ) {
OMPI_ERROR_LOG(ret);
goto done;
}
#endif
/* Free secondary resources */
/* free attr resources */
if (OMPI_SUCCESS != (ret = ompi_attr_finalize())) {
goto done;
}
/* free group resources */
if (OMPI_SUCCESS != (ret = ompi_group_finalize())) {
goto done;
}
/* finalize the DPM subsystem */
if ( OMPI_SUCCESS != (ret = ompi_dpm_finalize())) {
goto done;
}
/* free internal error resources */
if (OMPI_SUCCESS != (ret = ompi_errcode_intern_finalize())) {
goto done;
}
/* free error code resources */
if (OMPI_SUCCESS != (ret = ompi_mpi_errcode_finalize())) {
goto done;
}
/* free errhandler resources */
if (OMPI_SUCCESS != (ret = ompi_errhandler_finalize())) {
goto done;
}
/* Free all other resources */
/* free op resources */
if (OMPI_SUCCESS != (ret = ompi_op_finalize())) {
goto done;
}
/* free ddt resources */
if (OMPI_SUCCESS != (ret = ompi_datatype_finalize())) {
goto done;
}
/* free info resources */
if (OMPI_SUCCESS != (ret = ompi_info_finalize())) {
goto done;
}
/* Close down MCA modules */
/* io is opened lazily, so it's only necessary to close it if it
was actually opened */
if (0 < ompi_io_base_framework.framework_refcnt) {
/* May have been "opened" multiple times. We want it closed now */
ompi_io_base_framework.framework_refcnt = 1;
if (OMPI_SUCCESS != mca_base_framework_close(&ompi_io_base_framework)) {
goto done;
}
}
(void) mca_base_framework_close(&ompi_topo_base_framework);
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_osc_base_framework))) {
goto done;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_coll_base_framework))) {
goto done;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_bml_base_framework))) {
goto done;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&opal_mpool_base_framework))) {
goto done;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&opal_rcache_base_framework))) {
goto done;
}
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&opal_allocator_base_framework))) {
goto done;
}
/* free proc resources */
if ( OMPI_SUCCESS != (ret = ompi_proc_finalize())) {
goto done;
}
if (NULL != ompi_mpi_main_thread) {
OBJ_RELEASE(ompi_mpi_main_thread);
ompi_mpi_main_thread = NULL;
}
/* Clean up memory/resources from the MPI dynamic process
functionality checker */
ompi_mpi_dynamics_finalize();
/* Leave the RTE */
if (OMPI_SUCCESS != (ret = ompi_rte_finalize())) {
goto done;
}
ompi_rte_initialized = false;
/* now close the rte framework */
if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_rte_base_framework) ) ) {
OMPI_ERROR_LOG(ret);
goto done;
}
if (OPAL_SUCCESS != (ret = opal_finalize_util())) {
goto done;
}
/* All done */
done:
opal_mutex_unlock(&ompi_mpi_bootstrap_mutex);
return ret;
}
