openmpi/src/mca/coll/base/coll_base_find_available.c

/*
 * $HEADER$
 */

#include "ompi_config.h"

#include <stdio.h>
#include <stdlib.h>

#include "mpi.h"
#include "include/constants.h"
#include "class/ompi_list.h"
#include "util/output.h"
#include "mca/mca.h"
#include "mca/base/base.h"
#include "mca/coll/coll.h"
#include "mca/coll/base/base.h"


/*
 * Global variables
 */
bool mca_coll_base_components_available_valid = false;
ompi_list_t mca_coll_base_components_available;
const mca_coll_base_module_1_0_0_t *mca_coll_base_basic_component = NULL;


/*
 * Private functions
 */
static int init_query(const mca_base_module_t *ls, 
                      mca_base_component_priority_list_item_t *entry);
static int init_query_1_0_0(const mca_base_module_t *ls, 
                            mca_base_component_priority_list_item_t *entry);

/*
 * Scan down the list of successfully opened components and query each of
 * them (the opened list will be one or more components.  If the user
 * requested a specific component, it will be the only component in the
 * opened list).  Create and populate the available list of all
 * components who indicate that they want to be considered for selection.
 * Close all components who do not want to be considered for selection,
 * and destroy the opened list.
 *
 * Also find the basic component while we're doing all of this, and save
 * it in a global variable so that we can find it easily later (e.g.,
 * during scope selection).
 */
int mca_coll_base_find_available(bool *allow_multi_user_threads,
                                 bool *have_hidden_threads)
{
  bool found = false;
  mca_base_component_priority_list_item_t *entry;
  ompi_list_item_t *p;

  /* Initialize the list */

  OBJ_CONSTRUCT(&mca_coll_base_components_available, ompi_list_t);
  mca_coll_base_components_available_valid = true;

  /* The list of components that we should check has already been
     established in mca_coll_base_open. */
  
  for (found = false, 
         p = ompi_list_remove_first(&mca_coll_base_components_opened);
       p != NULL;
       p = ompi_list_remove_first(&mca_coll_base_components_opened)) {

    entry = OBJ_NEW(mca_base_component_priority_list_item_t);
    entry->cpli_component = ((mca_base_module_list_item_t *) p)->mli_module;

    /* Call a subroutine to do the work, because the component may
       represent different versions of the coll MCA. */
    
    if (init_query(entry->cpli_component, entry) == 0) {
      
      /* Is this the basic component?  If so, save it, because it's
         special.  Keep it off the available list -- we'll use it
         specially in the selection process. */

      if (0 == strcmp(entry->cpli_component->mca_module_name, "basic")) {
        mca_coll_base_basic_component = 
          (mca_coll_base_module_1_0_0_t *) entry->cpli_component;
      }

      /* Otherwise, save the results in the list.  The priority isn't
         relevant, because selection is decided at
         communicator-constructor time.  But we save the thread
         arguments (set in the init_query() function) so that the
         initial selection algorithm can negotiate the overall thread
         level for this process. */
      
      else {
        entry->cpli_priority = 0;
        ompi_list_append(&mca_coll_base_components_available, 
                         (ompi_list_item_t *) entry);
      }

      /* Either way, we found something :-) */

      found = true;
    } else {
      
      /* If the component doesn't want to run, then close it.  It's
         already had its close() method invoked; now close it out of
         the DSO repository (if it's there). */
      
      mca_base_module_repository_release(entry->cpli_component);
      OBJ_RELEASE(entry);
    }

    /* Free the entry from the "opened" list */

    free(p);
  }

  /* The opened list is now no longer useful and we can free it */
    
  OBJ_DESTRUCT(&mca_coll_base_components_opened);
  mca_coll_base_components_opened_valid = false;

  /* If we have no collective components available, it's an error.
     Thanks for playing! */
    
  if (!found) {
    /* Need to free all items in the list */
    OBJ_DESTRUCT(&mca_coll_base_components_available);
    mca_coll_base_components_available_valid = false;
    ompi_output_verbose(10, mca_coll_base_output,
                       "coll:find_available: no coll components available!");
    /* JMS show_help */
    return OMPI_ERROR;
  }

  /* All done */

  return OMPI_SUCCESS;
}


/*
 * Query a component, see if it wants to run at all.  If it does, save
 * some information.  If it doesn't, close it.
 */
static int init_query(const mca_base_module_t *m, 
                      mca_base_component_priority_list_item_t *entry)
{
  int ret;

  ompi_output_verbose(10, mca_coll_base_output,
                     "coll:find_available: querying coll component %s", 
                     m->mca_module_name);

  /* This component has already been successfully opened.  So now query
     it. */

  if (m->mca_type_major_version == 1 &&
      m->mca_type_minor_version == 0 &&
      m->mca_type_release_version == 0) {
    ret = init_query_1_0_0(m, entry);
  } else {
    /* Unrecognized coll API version */

    ompi_output_verbose(10, mca_coll_base_output,
                       "coll:find_available: unrecognized coll API version (%d.%d.%d)", 
                       m->mca_type_major_version,
                       m->mca_type_minor_version,
                       m->mca_type_release_version);
    /* JMS show_help */
    return OMPI_ERROR;
  }

  /* Query done -- look at the return value to see what happened */

  if (ret != 0) {
    ompi_output_verbose(10, mca_coll_base_output, 
                        "coll:find_available: coll component %s is not available", 
                        m->mca_module_name);
    if (NULL != m->mca_close_module) {
      m->mca_close_module();
    }
  } else {
    ompi_output_verbose(10, mca_coll_base_output, 
                        "coll:find_available: coll component %s is available", 
                        m->mca_module_name);
  }      

  /* All done */

  return ret;
}


/*
 * Query a specific component, coll v1.0.0
 */
static int 
init_query_1_0_0(const mca_base_module_t *component, 
                 mca_base_component_priority_list_item_t *entry)
{
    mca_coll_base_module_1_0_0_t *coll = 
	(mca_coll_base_module_1_0_0_t *) component;

    return coll->collm_init_query(&(entry->cpli_allow_multi_user_threads), 
				  &(entry->cpli_have_hidden_threads));
}