/*
 * Copyright (c) 2009-2012 Oak Ridge National Laboratory.  All rights reserved.
 * Copyright (c) 2009-2012 Mellanox Technologies.  All rights reserved.
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * $HEADER$
 */

/* Recursive doubling blocking barrier */

#include "ompi_config.h"
#include "ompi/constants.h"
#include "ompi/communicator/communicator.h"
#include "ompi/mca/bcol/bcol.h"
#include "ompi/mca/common/netpatterns/common_netpatterns.h"

#include "opal/sys/atomic.h"

#include "bcol_basesmuma.h"

/********************************************************************************/
/********************************** New Fan-In **********************************/
/********************************************************************************/

static int bcol_basesmuma_fanin_new(bcol_function_args_t *input_args,
                                    coll_ml_function_t *c_input_args)
{
    /* local variables */
    int64_t sequence_number;

    mca_bcol_basesmuma_module_t* bcol_module =
        (mca_bcol_basesmuma_module_t *) c_input_args->bcol_module;

    int i, child_rank, idx, n_children, probe, 
        my_rank = bcol_module->super.sbgp_partner_module->my_index,
        leading_dim = bcol_module->colls_no_user_data.size_of_group;
    int8_t  ready_flag;
    int8_t bcol_id = (int8_t) bcol_module->super.bcol_id;
    int buff_index = input_args->buffer_index;
    int *active_requests = 
        &(bcol_module->ml_mem.nb_coll_desc[buff_index].active_requests);
    mca_bcol_basesmuma_component_t *cm = &mca_bcol_basesmuma_component;
    int matched = 0; 

    
    volatile mca_bcol_basesmuma_payload_t *ctl_structs;

    /* control structures */
    volatile mca_bcol_basesmuma_header_t *my_ctl;
    volatile mca_bcol_basesmuma_header_t *child_ctl;


    mca_common_netpatterns_tree_node_t *my_tree_node = &(bcol_module->fanin_node);

    /* Figure out - what instance of the basesmuma bcol I am */
    sequence_number = input_args->sequence_num;

    idx = SM_ARRAY_INDEX(leading_dim, buff_index, 0);
    ctl_structs = (volatile mca_bcol_basesmuma_payload_t *)
                        bcol_module->colls_with_user_data.data_buffs + idx;
    my_ctl = ctl_structs[my_rank].ctl_struct;

    /* Init the header */
    BASESMUMA_HEADER_INIT(my_ctl, ready_flag, sequence_number, bcol_id);
    
    /* Cache num of children value in a local variable */
    n_children = my_tree_node->n_children;

    /* initialize the active requests */
    *active_requests = 0;
    /* create a bit map for children */
    for( i = 0; i < n_children; i++){
        *active_requests ^= (1<<i);
    }

    /* Wait until my childeren arrive */
    for (i = 0; i < n_children; ++i) {
        matched = 0;
        /* Get child ctl struct */
        child_rank = my_tree_node->children_ranks[i];
        child_ctl = ctl_structs[child_rank].ctl_struct;
        /* I'm sacrificing cache for concurrency */
        for( probe = 0; probe < cm->num_to_probe && (0 == matched); probe++){
            if(IS_PEER_READY(child_ctl, ready_flag, sequence_number,BARRIER_FANIN_FLAG, bcol_id)) {
                matched = 1;
                /* flip the bit */
                *active_requests ^= (1<<i);
            }
        }
    }
    
    if(0 == *active_requests ) {
        if(ROOT_NODE != my_tree_node->my_node_type){
            /* I have no more active requests, 
               signal my parent */
            my_ctl->flags[BARRIER_FANIN_FLAG][bcol_id] = ready_flag;
        }
    } else {
        return BCOL_FN_STARTED;
    }

    my_ctl->starting_flag_value[bcol_id]++;

    return BCOL_FN_COMPLETE;
}

static int bcol_basesmuma_fanin_new_progress(bcol_function_args_t *input_args,
                                    coll_ml_function_t *c_input_args)
{
    /* local variables */
    int64_t sequence_number;

    mca_bcol_basesmuma_module_t* bcol_module =
        (mca_bcol_basesmuma_module_t *) c_input_args->bcol_module;

    int i, child_rank, flag_offset, idx, n_children, probe, 
        my_rank = bcol_module->super.sbgp_partner_module->my_index,
        leading_dim = bcol_module->colls_no_user_data.size_of_group;
    int8_t  ready_flag;
    int8_t bcol_id = (int8_t) bcol_module->super.bcol_id;
    int buff_index = input_args->buffer_index;
    int *active_requests = 
        &(bcol_module->ml_mem.nb_coll_desc[buff_index].active_requests);
    mca_bcol_basesmuma_component_t *cm = &mca_bcol_basesmuma_component;
    int matched = 0; 

    
    volatile mca_bcol_basesmuma_payload_t *ctl_structs;

    /* control structures */
    volatile mca_bcol_basesmuma_header_t *my_ctl;
    volatile mca_bcol_basesmuma_header_t *child_ctl;


    mca_common_netpatterns_tree_node_t *my_tree_node = &(bcol_module->fanin_node);

    sequence_number = input_args->sequence_num;

    idx = SM_ARRAY_INDEX(leading_dim, buff_index, 0);
    ctl_structs = (volatile mca_bcol_basesmuma_payload_t *)
                        bcol_module->colls_with_user_data.data_buffs + idx;
    my_ctl = ctl_structs[my_rank].ctl_struct;


    flag_offset = my_ctl->starting_flag_value[bcol_id];
    ready_flag = flag_offset + 1;
    my_ctl->sequence_number = sequence_number;

    /* Cache num of children value in a local variable */
    n_children = my_tree_node->n_children;
    

    /* Wait until my childeren arrive */
    for (i = 0; i < n_children; ++i) {
        matched = 0;
        /* Get child ctl struct */
        if ( 1 == ((*active_requests >> i)&1) ) {
            child_rank = my_tree_node->children_ranks[i];
            child_ctl = ctl_structs[child_rank].ctl_struct;
            /* I'm sacrificing cache for concurrency */
            for( probe = 0; probe < cm->num_to_probe && (0 == matched); probe++){
                if(IS_PEER_READY(child_ctl, ready_flag, sequence_number, BARRIER_FANIN_FLAG,bcol_id)) {
                    matched = 1;
                    /* flip the bit */
                    *active_requests ^= (1<<i);
                }
            }
        }
    }
    if(0 == *active_requests ){
        if(ROOT_NODE != my_tree_node->my_node_type){ 
            /* If I am not the root of the fanin tree, 
               then signal my parent */
            my_ctl->flags[BARRIER_FANIN_FLAG][bcol_id] = ready_flag;
        }
    } else {
        return BCOL_FN_STARTED;
    }

    my_ctl->starting_flag_value[bcol_id]++;

    return BCOL_FN_COMPLETE;
}


int bcol_basesmuma_fanin_init(mca_bcol_base_module_t *super)
{
    mca_bcol_base_coll_fn_comm_attributes_t comm_attribs;
    mca_bcol_base_coll_fn_invoke_attributes_t inv_attribs;

    BASESMUMA_VERBOSE(10, ("Basesmuma Fan-In register.\n"));

    comm_attribs.bcoll_type = BCOL_FANIN;

    comm_attribs.comm_size_min = 0;
    comm_attribs.comm_size_max = 1024 * 1024;
    comm_attribs.waiting_semantics = NON_BLOCKING;

    inv_attribs.bcol_msg_min = 0;
    inv_attribs.bcol_msg_max = 20000; /* range 1 */

    inv_attribs.datatype_bitmap = 0xffffffff;
    inv_attribs.op_types_bitmap = 0xffffffff;

    comm_attribs.data_src = DATA_SRC_KNOWN;

    mca_bcol_base_set_attributes(super,
        &comm_attribs, &inv_attribs,
        bcol_basesmuma_fanin_new,
        bcol_basesmuma_fanin_new_progress);

    return OMPI_SUCCESS;
}