openmpi/ompi/mca/btl/sm/btl_sm.c

/*
 * Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2008 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2007 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 (c) 2006-2007 Voltaire. All rights reserved.
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * $HEADER$
 */

#include "ompi_config.h"

#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

#include "opal/threads/mutex.h"
#include "ompi/datatype/convertor.h"
#include "opal/sys/atomic.h"
#include "orte/util/output.h"
#include "opal/util/if.h"
#include "orte/util/proc_info.h"
#include "opal/util/printf.h"
#include "ompi/class/ompi_fifo.h"
#include "ompi/class/ompi_free_list.h"
#include "ompi/mca/pml/pml.h"
#include "ompi/mca/btl/btl.h"
#include "ompi/mca/mpool/base/base.h"
#include "ompi/mca/common/sm/common_sm_mmap.h"
#include "btl_sm.h"
#include "btl_sm_endpoint.h"
#include "btl_sm_frag.h"
#include "btl_sm_fifo.h"
#include "ompi/proc/proc.h"

mca_btl_sm_t mca_btl_sm = {
    {
        &mca_btl_sm_component.super,
        0, /* btl_eager_limit */
        0, /* btl_rndv_eager_limit */
        0, /* btl_max_send_size */
        0, /* btl_rdma_pipeline_send_length */
        0, /* btl_rdma_pipeline_frag_size */
        0, /* btl_min_rdma_pipeline_size */
        0, /* btl_exclusivity */
        0, /* btl_latency */
        0, /* btl_bandwidth */
        0, /* btl flags */
        mca_btl_sm_add_procs,
        mca_btl_sm_del_procs,
        NULL,
        mca_btl_sm_finalize,
        mca_btl_sm_alloc,
        mca_btl_sm_free,
        mca_btl_sm_prepare_src,
        NULL,
        mca_btl_sm_send,
        mca_btl_sm_sendi,  /* send immediate */
        NULL,  /* put */
        NULL,  /* get */
        mca_btl_base_dump,
        NULL, /* mpool */
        mca_btl_sm_register_error_cb, /* register error */
        mca_btl_sm_ft_event
    }
};

/*
 * calculate offset of an address from the beginning of a shared memory segment
 */
#define ADDR2OFFSET(ADDR, BASE) ((char*)(ADDR) - (char*)(BASE))

/*
 * calculate an absolute address in a local address space given an offset and
 * a base address of a shared memory segment
 */
#define OFFSET2ADDR(OFFSET, BASE) ((ptrdiff_t)(OFFSET) + (char*)(BASE))


static void *mpool_calloc(size_t nmemb, size_t size)
{
    void *buf;
    size_t bsize = nmemb * size;

    buf = mca_btl_sm_component.sm_mpool->mpool_alloc(
        mca_btl_sm_component.sm_mpool, bsize, CACHE_LINE_SIZE, 0, NULL);
    if (NULL == buf)
        return NULL;

    memset(buf, 0, bsize);
    return buf;
}

static int init_fifos(ompi_fifo_t *f, int n)
{
    int j;
    for(j=0; j < n; j++) {
        f[j].head = (ompi_cb_fifo_wrapper_t*)OMPI_CB_FREE;
        f[j].tail = (ompi_cb_fifo_wrapper_t*)OMPI_CB_FREE;
        if(opal_using_threads()) {
            char *buf = mpool_calloc(2, CACHE_LINE_SIZE);
            /* allocate head and tail locks on different cache lines */
            if(NULL == buf)
                return OMPI_ERROR;

            f[j].head_lock = (opal_atomic_lock_t*)buf;
            f[j].tail_lock = (opal_atomic_lock_t*)(buf + CACHE_LINE_SIZE);
            opal_atomic_init(f[j].head_lock, OPAL_ATOMIC_UNLOCKED);
            opal_atomic_init(f[j].tail_lock, OPAL_ATOMIC_UNLOCKED);
        } else {
            f[j].head_lock = NULL;
            f[j].tail_lock = NULL;
        }
    }

    return OMPI_SUCCESS;
}

static int sm_btl_first_time_init(mca_btl_sm_t *sm_btl, int n)
{
    size_t size, length, length_payload;
    char *sm_ctl_file;
    ompi_fifo_t *my_fifos;

    /* lookup shared memory pool */
    mca_btl_sm_component.sm_mpool =
        mca_mpool_base_module_lookup(mca_btl_sm_component.sm_mpool_name);
    if(NULL == mca_btl_sm_component.sm_mpool) {
        mca_btl_sm_component.sm_mpool =
            mca_mpool_base_module_create(mca_btl_sm_component.sm_mpool_name,
                                         sm_btl, NULL);
    }

    /* Sanity check to ensure that we found it */
    if(NULL == mca_btl_sm_component.sm_mpool)
        return OMPI_ERR_OUT_OF_RESOURCE;

    mca_btl_sm_component.sm_mpool_base =
        mca_btl_sm_component.sm_mpool->mpool_base(mca_btl_sm_component.sm_mpool);

    /* set the shared memory offset */
    mca_btl_sm_component.sm_offset = (ptrdiff_t*)calloc(n, sizeof(ptrdiff_t));
    if(NULL == mca_btl_sm_component.sm_offset)
        return OMPI_ERR_OUT_OF_RESOURCE;

    /* create a list of peers */
    mca_btl_sm_component.sm_peers = (struct mca_btl_base_endpoint_t**)
        calloc(n, sizeof(struct mca_btl_base_endpoint_t*));
    if(NULL == mca_btl_sm_component.sm_peers)
        return OMPI_ERR_OUT_OF_RESOURCE;

    /* Allocate Shared Memory BTL process coordination
     * data structure.  This will reside in shared memory */

    /* set file name */
    if(asprintf(&sm_ctl_file, "%s"OPAL_PATH_SEP"shared_mem_btl_module.%s",
                orte_process_info.job_session_dir,
                orte_process_info.nodename) < 0)
        return OMPI_ERR_OUT_OF_RESOURCE;

    /* Pass in a data segment alignment of 0 to get no data
       segment (only the shared control structure) */
    size = sizeof(mca_common_sm_file_header_t) +
        n * (sizeof(ompi_fifo_t*) + sizeof(char *)) + CACHE_LINE_SIZE;
    if(!(mca_btl_sm_component.mmap_file =
         mca_common_sm_mmap_init(size, sm_ctl_file,
                                 sizeof(mca_common_sm_file_header_t),
                                 CACHE_LINE_SIZE))) {
        orte_output(0, "mca_btl_sm_add_procs: unable to create shared memory "
                    "BTL coordinating strucure :: size %lu \n",
                    (unsigned long)size);
        free(sm_ctl_file);
        return OMPI_ERROR;
    }

    free(sm_ctl_file);

    /* set the pointer to the shared memory control structure */
    mca_btl_sm_component.sm_ctl_header =
        (mca_common_sm_file_header_t*)mca_btl_sm_component.mmap_file->map_seg;


    /* check to make sure number of local procs is within the
     * specified limits */
    if(mca_btl_sm_component.sm_max_procs > 0 &&
       mca_btl_sm_component.num_smp_procs + n >
       mca_btl_sm_component.sm_max_procs) {
        return OMPI_ERROR;
    }

    mca_btl_sm_component.shm_fifo = (ompi_fifo_t **)mca_btl_sm_component.mmap_file->data_addr;
    mca_btl_sm_component.shm_bases = (char**)(mca_btl_sm_component.shm_fifo + n);

    /* Sync with other local procs. (Do we have to?) */
    if(0 == mca_btl_sm_component.my_smp_rank) {
        mca_btl_sm_component.mmap_file->map_seg->seg_inited = true;

        /* memory barrier to ensure this flag is set before other
         *  flags are set */
        opal_atomic_wmb();
    } else {
        while(!mca_btl_sm_component.mmap_file->map_seg->seg_inited) {
            opal_atomic_rmb();
            opal_progress();
        }
    }

    /* set the base of the shared memory segment */
    mca_btl_sm_component.shm_bases[mca_btl_sm_component.my_smp_rank] =
        (char*)mca_btl_sm_component.sm_mpool_base;

    /*
     * initialize the array of fifo's "owned" by this process
     * The virtual addresses are valid only in the sender's
     * address space - unless the base of the shared memory
     * segment is mapped at the same location in the reader's
     * virtual address space.
     */
    if(NULL == (my_fifos = (ompi_fifo_t*)mpool_calloc(n, sizeof(ompi_fifo_t))))
        return OMPI_ERR_OUT_OF_RESOURCE;

    if(init_fifos(my_fifos, n) != OMPI_SUCCESS)
        return OMPI_ERR_OUT_OF_RESOURCE;

    mca_btl_sm_component.shm_fifo[mca_btl_sm_component.my_smp_rank] = my_fifos;

    opal_atomic_wmb();

    /* cache the pointer to the 2d fifo array.  These addresses
     * are valid in the current process space */
    mca_btl_sm_component.fifo = (ompi_fifo_t**)malloc(sizeof(ompi_fifo_t*) * n);

    if(NULL == mca_btl_sm_component.fifo)
        return OMPI_ERR_OUT_OF_RESOURCE;

    mca_btl_sm_component.fifo[mca_btl_sm_component.my_smp_rank] = my_fifos;

    /* initialize fragment descriptor free lists */

    /* allocation will be for the fragment descriptor and payload buffer */
    length = sizeof(mca_btl_sm_frag1_t);
    length_payload =
        sizeof(mca_btl_sm_hdr_t) + mca_btl_sm_component.eager_limit;
    ompi_free_list_init_new(&mca_btl_sm_component.sm_frags_eager, length,
                            CACHE_LINE_SIZE, OBJ_CLASS(mca_btl_sm_frag1_t),
                            length_payload, CACHE_LINE_SIZE,
                            mca_btl_sm_component.sm_free_list_num,
                            mca_btl_sm_component.sm_free_list_max,
                            mca_btl_sm_component.sm_free_list_inc,
                            mca_btl_sm_component.sm_mpool);

    length = sizeof(mca_btl_sm_frag2_t);
    length_payload =
        sizeof(mca_btl_sm_hdr_t) + mca_btl_sm_component.max_frag_size;
    ompi_free_list_init_new(&mca_btl_sm_component.sm_frags_max, length,
                            CACHE_LINE_SIZE, OBJ_CLASS(mca_btl_sm_frag2_t),
                            length_payload, CACHE_LINE_SIZE,
                            mca_btl_sm_component.sm_free_list_num,
                            mca_btl_sm_component.sm_free_list_max,
                            mca_btl_sm_component.sm_free_list_inc,
                            mca_btl_sm_component.sm_mpool);

    opal_free_list_init(&mca_btl_sm_component.pending_send_fl,
                        sizeof(btl_sm_pending_send_item_t),
                        OBJ_CLASS(opal_free_list_item_t),
                        16, -1, 32);

    /* set flag indicating btl has been inited */
    sm_btl->btl_inited = true;

    return OMPI_SUCCESS;
}

static struct mca_btl_base_endpoint_t *
create_sm_endpoint(int local_proc, struct ompi_proc_t *proc)
{
    struct mca_btl_base_endpoint_t *ep;
#if OMPI_ENABLE_PROGRESS_THREADS == 1
    char path[PATH_MAX];
#endif

    ep = (struct mca_btl_base_endpoint_t*)
        malloc(sizeof(struct mca_btl_base_endpoint_t));
    if(NULL == ep)
        return NULL;
    ep->peer_smp_rank = local_proc + mca_btl_sm_component.num_smp_procs;

    OBJ_CONSTRUCT(&ep->pending_sends, opal_list_t);
#if OMPI_ENABLE_PROGRESS_THREADS == 1
    sprintf(path, "%s"OPAL_PATH_SEP"sm_fifo.%lu",
            orte_process_info.job_session_dir,
            (unsigned long)proc->proc_name.vpid);
    ep->fifo_fd = open(path, O_WRONLY);
    if(ep->fifo_fd < 0) {
        orte_output(0, "mca_btl_sm_add_procs: open(%s) failed with errno=%d\n",
                    path, errno);
        free(ep);
        return NULL;
    }
#endif
    return ep;
}

static void calc_sm_max_procs(int n)
{
    /* see if need to allocate space for extra procs */
    if(0 > mca_btl_sm_component.sm_max_procs) {
        /* no limit */
        if(0 <= mca_btl_sm_component.sm_extra_procs) {
            /* limit */
            mca_btl_sm_component.sm_max_procs =
                n + mca_btl_sm_component.sm_extra_procs;
        } else {
            /* no limit */
            mca_btl_sm_component.sm_max_procs = 2 * n;
        }
    }
}

int mca_btl_sm_add_procs(
    struct mca_btl_base_module_t* btl,
    size_t nprocs,
    struct ompi_proc_t **procs,
    struct mca_btl_base_endpoint_t **peers,
    ompi_bitmap_t* reachability)
{
    int return_code = OMPI_SUCCESS;
    int32_t n_local_procs = 0, proc, j,
        my_smp_rank = mca_btl_sm_component.my_smp_rank;
    ompi_proc_t* my_proc; /* pointer to caller's proc structure */
    mca_btl_sm_t *sm_btl;
    bool have_connected_peer = false;
    char **bases;
    /* initializion */

    sm_btl = (mca_btl_sm_t *)btl;

    /* get pointer to my proc structure */
    if(NULL == (my_proc = ompi_proc_local()))
        return OMPI_ERR_OUT_OF_RESOURCE;

    /* Get unique host identifier for each process in the list,
     * and idetify procs that are on this host.  Add procs on this
     * host to shared memory reachbility list.  Also, get number
     * of local procs in the procs list. */
    for(proc = 0; proc < (int32_t)nprocs; proc++) {
        /* check to see if this proc can be reached via shmem (i.e.,
           if they're on my local host and in my job) */
        if (procs[proc]->proc_name.jobid != my_proc->proc_name.jobid ||
                 0 == (procs[proc]->proc_flags & OMPI_PROC_FLAG_LOCAL)) {
            peers[proc] = NULL;
            continue;
        }

        /* check to see if this is me */
        if(my_proc == procs[proc]) {
            my_smp_rank = mca_btl_sm_component.my_smp_rank = n_local_procs++;
            continue;
        }

        /* we have someone to talk to */
        have_connected_peer = true;

        if(!(peers[proc] = create_sm_endpoint(n_local_procs, procs[proc]))) {
            return_code = OMPI_ERROR;
            goto CLEANUP;
        }
        n_local_procs++;

        /* add this proc to shared memory accessibility list */
        return_code = ompi_bitmap_set_bit(reachability, proc);
        if(OMPI_SUCCESS != return_code)
            goto CLEANUP;
    }

    /* jump out if there's not someone we can talk to */
    if (!have_connected_peer)
        goto CLEANUP;

    /* make sure that my_smp_rank has been defined */
    if(-1 == my_smp_rank) {
        return_code = OMPI_ERROR;
        goto CLEANUP;
    }

    calc_sm_max_procs(n_local_procs);

    if (!sm_btl->btl_inited) {
        return_code =
            sm_btl_first_time_init(sm_btl, mca_btl_sm_component.sm_max_procs);
        if(return_code != OMPI_SUCCESS)
            goto CLEANUP;
    }

    /* set local proc's smp rank in the peers structure for
     * rapid access and calulcate reachebility */
    for(proc = 0; proc < (int32_t)nprocs; proc++) {
        if(NULL == peers[proc])
            continue;
        mca_btl_sm_component.sm_peers[peers[proc]->peer_smp_rank] = peers[proc];
        peers[proc]->my_smp_rank = my_smp_rank;
    }

    bases = mca_btl_sm_component.shm_bases;

    for(j = mca_btl_sm_component.num_smp_procs;
        j < mca_btl_sm_component.num_smp_procs + n_local_procs; j++) {
        ptrdiff_t diff;

        if(j == my_smp_rank)
            continue;

        /* spin until this element is allocated */
        while(NULL == mca_btl_sm_component.shm_fifo[j]) {
            opal_atomic_rmb();
            opal_progress();
        }

        /* Calculate the difference as (my_base - their_base) */
        diff = ADDR2OFFSET(bases[my_smp_rank], bases[j]);
        mca_btl_sm_component.sm_offset[j] = diff;

        /* store local address of remote fifos */
        mca_btl_sm_component.fifo[j] =
            (ompi_fifo_t*)OFFSET2ADDR(diff, mca_btl_sm_component.shm_fifo[j]);

        /* don't forget to update the head_lock if allocated because this
         * address is also in the remote process */
        if(mca_btl_sm_component.fifo[j][my_smp_rank].head_lock != NULL) {
            mca_btl_sm_component.fifo[j][my_smp_rank].head_lock =
                (opal_atomic_lock_t*)OFFSET2ADDR(diff, mca_btl_sm_component.fifo[j][my_smp_rank].head_lock);
        }

        /* Initialize fifo for use. Note that sender does initialization */
        return_code = ompi_fifo_init(mca_btl_sm_component.size_of_cb_queue,
                                     mca_btl_sm_component.cb_lazy_free_freq,
                                     mca_btl_sm_component.cb_max_num,
                                     0,0,0,
                                     &mca_btl_sm_component.fifo[j][my_smp_rank],
                                     mca_btl_sm_component.sm_offset[j],
                                     mca_btl_sm_component.sm_mpool);

        if(return_code != OMPI_SUCCESS)
            goto CLEANUP;
    }

    /* update the local smp process count */
    mca_btl_sm_component.num_smp_procs += n_local_procs;

    /* make sure we have enough eager fragmnents for each process */
    return_code = ompi_free_list_resize(&mca_btl_sm_component.sm_frags_eager,
                                        mca_btl_sm_component.num_smp_procs * 2);
    if (OMPI_SUCCESS != return_code)
        goto CLEANUP;

CLEANUP:
    return return_code;
}

int mca_btl_sm_del_procs(
    struct mca_btl_base_module_t* btl,
    size_t nprocs,
    struct ompi_proc_t **procs,
    struct mca_btl_base_endpoint_t **peers)
{
    return OMPI_SUCCESS;
}


/**
 * MCA->BTL Clean up any resources held by BTL module
 * before the module is unloaded.
 *
 * @param btl (IN)   BTL module.
 *
 * Prior to unloading a BTL module, the MCA framework will call
 * the BTL finalize method of the module. Any resources held by
 * the BTL should be released and if required the memory corresponding
 * to the BTL module freed.
 *
 */

int mca_btl_sm_finalize(struct mca_btl_base_module_t* btl)
{
    return OMPI_SUCCESS;
}


/*
 * Register callback function for error handling..
 */
int mca_btl_sm_register_error_cb(
        struct mca_btl_base_module_t* btl,
        mca_btl_base_module_error_cb_fn_t cbfunc)
{
    mca_btl_sm_t *sm_btl = (mca_btl_sm_t *)btl;
    sm_btl->error_cb = cbfunc;
    return OMPI_SUCCESS;
}

/**
 * Allocate a segment.
 *
 * @param btl (IN)      BTL module
 * @param size (IN)     Request segment size.
 */
extern mca_btl_base_descriptor_t* mca_btl_sm_alloc(
    struct mca_btl_base_module_t* btl,
    struct mca_btl_base_endpoint_t* endpoint,
    uint8_t order,
    size_t size,
    uint32_t flags)
{
    mca_btl_sm_frag_t* frag;
    int rc;
    if(size <= mca_btl_sm_component.eager_limit) {
        MCA_BTL_SM_FRAG_ALLOC1(frag,rc);
    } else if (size <= mca_btl_sm_component.max_frag_size) {
        MCA_BTL_SM_FRAG_ALLOC2(frag,rc);
    } else {
        return NULL;
    }

    if (frag != NULL) {
        frag->segment.seg_len = size;
        frag->base.des_flags = flags;
    }

    return (mca_btl_base_descriptor_t*)frag;
}

/**
 * Return a segment allocated by this BTL.
 *
 * @param btl (IN)      BTL module
 * @param segment (IN)  Allocated segment.
 */
extern int mca_btl_sm_free(
    struct mca_btl_base_module_t* btl,
    mca_btl_base_descriptor_t* des)
{
    mca_btl_sm_frag_t* frag = (mca_btl_sm_frag_t*)des;
    MCA_BTL_SM_FRAG_RETURN(frag);

    return OMPI_SUCCESS;
}


/**
 * Pack data
 *
 * @param btl (IN)      BTL module
 */
struct mca_btl_base_descriptor_t* mca_btl_sm_prepare_src(
    struct mca_btl_base_module_t* btl,
    struct mca_btl_base_endpoint_t* endpoint,
    mca_mpool_base_registration_t* registration,
    struct ompi_convertor_t* convertor,
    uint8_t order,
    size_t reserve,
    size_t* size,
    uint32_t flags)
{
    mca_btl_sm_frag_t* frag;
    struct iovec iov;
    uint32_t iov_count = 1;
    size_t max_data = *size;
    int rc;

    MCA_BTL_SM_FRAG_ALLOC2(frag, rc);
    if(NULL == frag) {
        return NULL;
    }

    if(reserve + max_data > frag->size) {
        max_data = frag->size - reserve;
    }
    iov.iov_len = max_data;
    iov.iov_base =
        (IOVBASE_TYPE*)(((unsigned char*)(frag->segment.seg_addr.pval)) +
                reserve);

    rc = ompi_convertor_pack(convertor, &iov, &iov_count, &max_data );
    if(rc < 0) {
        MCA_BTL_SM_FRAG_RETURN(frag);
        return NULL;
    }
    frag->segment.seg_len = reserve + max_data;
    frag->base.des_flags = flags;
    *size = max_data;
    return &frag->base;
}

#if 0
#define MCA_BTL_SM_TOUCH_DATA_TILL_CACHELINE_BOUNDARY(sm_frag)          \
    do {                                                                \
        char* _memory = (char*)(sm_frag)->segment.seg_addr.pval +       \
            (sm_frag)->segment.seg_len;                                 \
        int* _intmem;                                                   \
        size_t align = (intptr_t)_memory & 0xFUL;                       \
        switch( align & 0x3 ) {                                         \
        case 3: *_memory = 0; _memory++;                                \
        case 2: *_memory = 0; _memory++;                                \
        case 1: *_memory = 0; _memory++;                                \
        }                                                               \
        align >>= 2;                                                    \
        _intmem = (int*)_memory;                                        \
        switch( align ) {                                               \
        case 3: *_intmem = 0; _intmem++;                                \
        case 2: *_intmem = 0; _intmem++;                                \
        case 1: *_intmem = 0; _intmem++;                                \
        }                                                               \
    } while(0)
#else
#define MCA_BTL_SM_TOUCH_DATA_TILL_CACHELINE_BOUNDARY(sm_frag)
#endif

#if 0
        if( OPAL_LIKELY(align > 0) ) {                                  \
            align = 0xFUL - align;                                      \
            memset( _memory, 0, align );                                \
        }                                                               \

#endif

/**
 * Initiate an inline send to the peer. If failure then return a descriptor.
 *
 * @param btl (IN)      BTL module
 * @param peer (IN)     BTL peer addressing
 */
int mca_btl_sm_sendi( struct mca_btl_base_module_t* btl,
                      struct mca_btl_base_endpoint_t* endpoint,
                      struct ompi_convertor_t* convertor,
                      void* header,
                      size_t header_size,
                      size_t payload_size,
                      uint8_t order,
                      uint32_t flags,
                      mca_btl_base_tag_t tag,
                      mca_btl_base_descriptor_t** descriptor )
{
    size_t max_data, length = (header_size + payload_size);
    mca_btl_sm_frag_t* frag;
    int rc;

    if( length < mca_btl_sm_component.eager_limit ) {
        MCA_BTL_SM_FRAG_ALLOC1(frag, rc);
        if( OPAL_UNLIKELY(NULL == frag) ) {
            *descriptor = NULL;
            return rc;
        }
        frag->segment.seg_len = length;
        frag->hdr->len = length;
        assert( 0 == (flags & MCA_BTL_DES_SEND_ALWAYS_CALLBACK) );
        frag->base.des_flags = flags | MCA_BTL_DES_FLAGS_BTL_OWNERSHIP;
        frag->hdr->tag = tag;
        frag->endpoint = endpoint;

        memcpy( frag->segment.seg_addr.pval, header, header_size );
        if( payload_size ) {
            struct iovec iov;
            unsigned int iov_count;
            /* pack the data into the supplied buffer */
            iov.iov_base = (IOVBASE_TYPE*)((unsigned char*)frag->segment.seg_addr.pval + header_size);
            iov.iov_len  = payload_size;
            iov_count    = 1;

            (void)ompi_convertor_pack( convertor,
                                       &iov, &iov_count, &max_data);

            assert(max_data == payload_size);
        }
        MCA_BTL_SM_TOUCH_DATA_TILL_CACHELINE_BOUNDARY(frag);
        /*
         * post the descriptor in the queue - post with the relative
         * address
         */
        MCA_BTL_SM_FIFO_WRITE(endpoint, endpoint->my_smp_rank,
                              endpoint->peer_smp_rank, frag->hdr, false, rc);
        return rc;
    }
    *descriptor = mca_btl_sm_alloc( btl, endpoint, order,
                                    payload_size + header_size, flags);
    return OMPI_ERR_RESOURCE_BUSY;
}

/**
 * Initiate a send to the peer.
 *
 * @param btl (IN)      BTL module
 * @param peer (IN)     BTL peer addressing
 */
int mca_btl_sm_send(
    struct mca_btl_base_module_t* btl,
    struct mca_btl_base_endpoint_t* endpoint,
    struct mca_btl_base_descriptor_t* descriptor,
    mca_btl_base_tag_t tag)
{
    mca_btl_sm_frag_t* frag = (mca_btl_sm_frag_t*)descriptor;
    int rc;

    /* available header space */
    frag->hdr->len = frag->segment.seg_len;
    /* type of message, pt-2-pt, one-sided, etc */
    frag->hdr->tag = tag;

    MCA_BTL_SM_TOUCH_DATA_TILL_CACHELINE_BOUNDARY(frag);

    frag->endpoint = endpoint;

    /*
     * post the descriptor in the queue - post with the relative
     * address
     */
    MCA_BTL_SM_FIFO_WRITE(endpoint, endpoint->my_smp_rank,
                          endpoint->peer_smp_rank, frag->hdr, false, rc);
    return (rc < 0 ? rc : 1);
}

int mca_btl_sm_ft_event(int state) {
    if(OPAL_CRS_CHECKPOINT == state) {
        ;
    }
    else if(OPAL_CRS_CONTINUE == state) {
        ;
    }
    else if(OPAL_CRS_RESTART == state) {
        ;
    }
    else if(OPAL_CRS_TERM == state ) {
        ;
    }
    else {
        ;
    }

    return OMPI_SUCCESS;
}