Hi.
I have an issue with understanding /ompi_mpi_init() /logic. Could you
please tell me if you have any guesses about following behavior.
I wonder if I understand ringh, there is a block in /ompi_mpi_init()
/function for exchanging procs information between processes (denote
this block 'modex'):
coll = OBJ_NEW(orte_grpcomm_collective_t);
coll->id = orte_process_info.peer_modex;
if (ORTE_SUCCESS != (ret = orte_grpcomm.modex(coll))) {
error = "orte_grpcomm_modex failed";
goto error;
}
/* wait for modex to complete - this may be moved anywhere in
mpi_init
* so long as it occurs prior to calling a function that needs
* the modex info!
*/
while (coll->active) {
opal_progress(); /* block in progress pending events */
}
OBJ_RELEASE(coll);
and several instructions after this there is a block for processes
synchronization (denote this block 'barrier'):
coll = OBJ_NEW(orte_grpcomm_collective_t);
coll->id = orte_process_info.peer_init_barrier;
if (ORTE_SUCCESS != (ret = orte_grpcomm.barrier(coll))) {
error = "orte_grpcomm_barrier failed";
goto error;
}
/* wait for barrier to complete */
while (coll->active) {
opal_progress(); /* block in progress pending events */
}
OBJ_RELEASE(coll);
So,//initially///ompi_mpi_init()/ has following structure:
...
'modex' block;
...
'barrier' block;
...
I made several experiments with this code and the following one is of
interest: if I add sequence of two additional blocks, 'barrier' and
'modex', right after 'modex' block, then///ompi_mpi_init() /hangs in
/opal_progress()/ of the last 'modex' block.
...
'modex' block;
'barrier' block;
'modex' block; <- hangs
...
'barrier' block;
...
Thanks,
Victor Kocheganov.
