openmpi/opal/mca/maffinity/base/base.h

/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University.
 *                         All rights reserved.
 * Copyright (c) 2004-2005 The Trustees of the University of Tennessee.
 *                         All rights reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 *
 */

#ifndef OPAL_MAFFINITY_BASE_H
#define OPAL_MAFFINITY_BASE_H

#include "ompi_config.h"

#include "mca/maffinity/maffinity.h"


/*
 * Global functions for MCA overall maffinity open and close
 */

#if defined(c_plusplus) || defined(__cplusplus)
extern "C" {
#endif

    /**
     * Initialize the maffinity MCA framework
     *
     * @retval OPAL_SUCCESS Upon success
     * @retval OPAL_ERROR Upon failure
     *
     * This must be the first function invoked in the maffinity MCA
     * framework.  It initializes the maffinity MCA framework, finds
     * and opens maffinity components, etc.
     *
     * This function fills in the internal global variable
     * opal_maffinity_base_components_opened, which is a list of all
     * maffinity components that were successfully opened.  This
     * variable should \em only be used by other maffinity base
     * functions -- it is not considered a public interface member --
     * and is only mentioned here for completeness.
     */
    OMPI_DECLSPEC int opal_maffinity_base_open(void);
    
    /**
     * Select an available component.
     *
     * @return OPAL_SUCCESS Upon success.
     * @return OPAL_NOT_FOUND If no component can be selected.
     * @return OPAL_ERROR Upon other failure.
     *
     * This function invokes the selection process for maffinity
     * components, which works as follows:
     *
     * - If the \em maffinity MCA parameter is not specified, the
     *   selection set is all available maffinity components.
     * - If the \em maffinity MCA parameter is specified, the
     *   selection set is just that component.
     * - All components in the selection set are queried to see if
     *   they want to run.  All components that want to run are ranked
     *   by their priority and the highest priority component is
     *   selected.  All non-selected components have their "close"
     *   function invoked to let them know that they were not selected.
     * - The selected component will have its "init" function invoked to
     *   let it know that it was selected.
     *
     * If we fall through this entire process and no component is
     * selected, then return OPAL_NOT_FOUND (this is not a fatal
     * error).
     *
     * At the end of this process, we'll either have a single
     * component that is selected and initialized, or no component was
     * selected.  If no component was selected, subsequent invocation
     * of the maffinity wrapper functions will return an error.
     */
    OMPI_DECLSPEC int opal_maffinity_base_select(void);

    /**
     * Set memory affinity.
     *
     * @param segments Array describing segments and what process they
     * belong to
     * @param num_segments Length of the segments array
     * @param am_allocator True if this process created the shared
     * memory block
     *
     * @retval OPAL_SUCCESS upon success
     * @retval OPAL_NOT_FOUND if no maffinity components are available.
     * @retval OPAL_ERROR upon other error.
     *
     * Set the affinity of the memory segments described in the \em
     * segments array.
     *
     * If no maffinity components were available, or if the
     * opal_maffinity_base_select() was never invoked, OPAL_NOT_FOUND
     * is returned.
     */
    OMPI_DECLSPEC int opal_maffinity_base_set(opal_maffinity_base_segment_t *segments, size_t num_segments, bool am_allocator);

    /**
     * Shut down the maffinity MCA framework.
     *
     * @retval OPAL_SUCCESS Always
     *
     * This function shuts down everything in the maffinity MCA
     * framework.
     *
     * It must be the last function invoked on the maffinity MCA
     * framework.
     */
    OMPI_DECLSPEC int opal_maffinity_base_close(void);
    
#if defined(c_plusplus) || defined(__cplusplus)
}
#endif
#endif /* OPAL_BASE_MAFFINITY_H */