#include "private.h"
-
-SMPI_MPI_Global_t smpi_mpi_global = NULL;
-
-void smpi_mpi_land_func(void *x, void *y, void *z)
+#include "xbt/time.h"
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_base, smpi,
+ "Logging specific to SMPI (base)");
+XBT_LOG_EXTERNAL_CATEGORY(smpi_base);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_bench);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_kernel);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_mpi);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_mpi_dt);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_coll);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_receiver);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_sender);
+XBT_LOG_EXTERNAL_CATEGORY(smpi_util);
+
+smpi_mpi_global_t smpi_mpi_global = NULL;
+
+
+/**
+ * Operations of MPI_OP : implemented=land,sum,min,max
+ **/
+void smpi_mpi_land_func(void *a, void *b, int *length,
+ MPI_Datatype * datatype);
+
+void smpi_mpi_land_func(void *a, void *b, int *length,
+ MPI_Datatype * datatype)
{
- *(int *)z = *(int *)x && *(int *)y;
+ int i;
+ if (*datatype == smpi_mpi_global->mpi_int) {
+ int *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] && y[i];
+ }
+ }
}
-void smpi_mpi_sum_func(void *x, void *y, void *z)
+/**
+ * sum two vectors element-wise
+ *
+ * @param a the first vectors
+ * @param b the second vectors
+ * @return the second vector is modified and contains the element-wise sums
+ **/
+void smpi_mpi_sum_func(void *a, void *b, int *length,
+ MPI_Datatype * datatype);
+
+void smpi_mpi_sum_func(void *a, void *b, int *length, MPI_Datatype * datatype)
{
- *(int *)z = *(int *)x + *(int *)y;
+ int i;
+ if ((*datatype == smpi_mpi_global->mpi_byte) || (*datatype == smpi_mpi_global->mpi_char)) {
+ char *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] + y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_int) {
+ int *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] + y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_float) {
+ float *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] + y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_double) {
+ double *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] + y[i];
+ }
+ }
}
-
-int inline smpi_mpi_comm_size(smpi_mpi_communicator_t comm)
+/**
+ *i multiply two vectors element-wise
+ *
+ * @param a the first vectors
+ * @param b the second vectors
+ * @return the second vector is modified and contains the element-wise products
+ **/
+void smpi_mpi_prod_func(void *a, void *b, int *length,
+ MPI_Datatype * datatype);
+
+void smpi_mpi_prod_func(void *a, void *b, int *length, MPI_Datatype * datatype)
{
- return comm->size;
+ int i;
+ if ((*datatype == smpi_mpi_global->mpi_byte) || (*datatype == smpi_mpi_global->mpi_char)) {
+ char *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] * y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_int) {
+ int *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] * y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_float) {
+ float *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] * y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_double) {
+ double *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] * y[i];
+ }
+ }
}
+/**
+ * compute the min of two vectors element-wise
+ **/
+void smpi_mpi_min_func(void *a, void *b, int *length,
+ MPI_Datatype * datatype);
-// FIXME: smarter algorithm?
-int smpi_mpi_comm_rank(smpi_mpi_communicator_t comm, smx_host_t host)
+void smpi_mpi_min_func(void *a, void *b, int *length, MPI_Datatype * datatype)
{
- int i;
-
- for(i = comm->size - 1; i > 0 && host != comm->hosts[i]; i--);
-
- return i;
+ int i;
+ if ((*datatype == smpi_mpi_global->mpi_byte) || (*datatype == smpi_mpi_global->mpi_char)) {
+ char *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] < y[i] ? x[i] : y[i];
+ }
+ } else {
+ if (*datatype == smpi_mpi_global->mpi_int) {
+ int *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] < y[i] ? x[i] : y[i];
+ }
+ } else {
+ if (*datatype == smpi_mpi_global->mpi_float) {
+ float *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] < y[i] ? x[i] : y[i];
+ }
+ } else {
+ if (*datatype == smpi_mpi_global->mpi_double) {
+ double *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] < y[i] ? x[i] : y[i];
+ }
+
+ }
+ }
+ }
+ }
}
-int inline smpi_mpi_comm_rank_self(smpi_mpi_communicator_t comm)
-{
- return smpi_mpi_comm_rank(comm, SIMIX_host_self());
-}
+/**
+ * compute the max of two vectors element-wise
+ **/
+void smpi_mpi_max_func(void *a, void *b, int *length,
+ MPI_Datatype * datatype);
-void smpi_mpi_init()
+void smpi_mpi_max_func(void *a, void *b, int *length, MPI_Datatype * datatype)
{
- smx_process_t process;
- smx_host_t host;
- smx_host_t *hosts;
- int size;
-
- SIMIX_mutex_lock(smpi_global->running_hosts_count_mutex);
- smpi_global->running_hosts_count++;
- SIMIX_mutex_unlock(smpi_global->running_hosts_count_mutex);
-
- // initialize some local variables
- process = SIMIX_process_self();
- host = SIMIX_host_self();
- hosts = SIMIX_host_get_table();
- size = SIMIX_host_get_number();
-
- // node 0 sets the globals
- if (host == hosts[0]) {
-
- smpi_mpi_global = xbt_new(s_SMPI_MPI_Global_t, 1);
-
- // global communicator
- smpi_mpi_global->mpi_comm_world = xbt_new(s_smpi_mpi_communicator_t, 1);
- smpi_mpi_global->mpi_comm_world->size = size;
- smpi_mpi_global->mpi_comm_world->hosts = hosts;
- smpi_mpi_global->mpi_comm_world->processes = xbt_new(smx_process_t, size);
- smpi_mpi_global->mpi_comm_world->processes[0] = process;
- smpi_mpi_global->mpi_comm_world->barrier_count = 0;
- smpi_mpi_global->mpi_comm_world->barrier_mutex = SIMIX_mutex_init();
- smpi_mpi_global->mpi_comm_world->barrier_cond = SIMIX_cond_init();
-
- // mpi datatypes
- smpi_mpi_global->mpi_byte = xbt_new(s_smpi_mpi_datatype_t, 1);
- smpi_mpi_global->mpi_byte->size = (size_t)1;
- smpi_mpi_global->mpi_int = xbt_new(s_smpi_mpi_datatype_t, 1);
- smpi_mpi_global->mpi_int->size = sizeof(int);
- smpi_mpi_global->mpi_double = xbt_new(s_smpi_mpi_datatype_t, 1);
- smpi_mpi_global->mpi_double->size = sizeof(double);
-
- // mpi operations
- smpi_mpi_global->mpi_land = xbt_new(s_smpi_mpi_op_t, 1);
- smpi_mpi_global->mpi_land->func = smpi_mpi_land_func;
- smpi_mpi_global->mpi_sum = xbt_new(s_smpi_mpi_op_t, 1);
- smpi_mpi_global->mpi_sum->func = smpi_mpi_sum_func;
-
- // signal all nodes to perform initialization
- SIMIX_mutex_lock(smpi_global->start_stop_mutex);
- smpi_global->root_ready = 1;
- SIMIX_cond_broadcast(smpi_global->start_stop_cond);
- SIMIX_mutex_unlock(smpi_global->start_stop_mutex);
-
- } else {
-
- // make sure root is done before own initialization
- SIMIX_mutex_lock(smpi_global->start_stop_mutex);
- if (!smpi_global->root_ready) {
- SIMIX_cond_wait(smpi_global->start_stop_cond, smpi_global->start_stop_mutex);
- }
- SIMIX_mutex_unlock(smpi_global->start_stop_mutex);
-
- smpi_mpi_global->mpi_comm_world->processes[smpi_mpi_comm_rank_self(smpi_mpi_global->mpi_comm_world)] = process;
- }
-
- // wait for all nodes to signal initializatin complete
- SIMIX_mutex_lock(smpi_global->start_stop_mutex);
- smpi_global->ready_process_count++;
- if (smpi_global->ready_process_count < 3 * size) {
- SIMIX_cond_wait(smpi_global->start_stop_cond, smpi_global->start_stop_mutex);
- } else {
- SIMIX_cond_broadcast(smpi_global->start_stop_cond);
- }
- SIMIX_mutex_unlock(smpi_global->start_stop_mutex);
-
- return;
+ int i;
+ if ((*datatype == smpi_mpi_global->mpi_byte) || (*datatype == smpi_mpi_global->mpi_char)) {
+ char *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] > y[i] ? x[i] : y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_int) {
+ int *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] > y[i] ? x[i] : y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_float) {
+ float *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] > y[i] ? x[i] : y[i];
+ }
+ } else if (*datatype == smpi_mpi_global->mpi_double) {
+ double *x = a, *y = b;
+ for (i = 0; i < *length; i++) {
+ y[i] = x[i] > y[i] ? x[i] : y[i];
+ }
+
+ }
}
-void smpi_mpi_finalize()
-{
- int i;
- int rank = smpi_mpi_comm_rank_self(smpi_mpi_global->mpi_comm_world);
-
- SIMIX_mutex_lock(smpi_global->running_hosts_count_mutex);
- i = --smpi_global->running_hosts_count;
- SIMIX_mutex_unlock(smpi_global->running_hosts_count_mutex);
-
- SIMIX_mutex_lock(smpi_global->start_stop_mutex);
- smpi_global->ready_process_count--;
- SIMIX_mutex_unlock(smpi_global->start_stop_mutex);
- if (0 >= i) {
- // wake up senders/receivers
- for (i = 0; i < smpi_mpi_global->mpi_comm_world->size; i++) {
- if (SIMIX_process_is_suspended(smpi_global->sender_processes[i])) {
- SIMIX_process_resume(smpi_global->sender_processes[i]);
- }
- if (SIMIX_process_is_suspended(smpi_global->receiver_processes[i])) {
- SIMIX_process_resume(smpi_global->receiver_processes[i]);
- }
- }
- SIMIX_mutex_destroy(smpi_mpi_global->mpi_comm_world->barrier_mutex);
- SIMIX_cond_destroy(smpi_mpi_global->mpi_comm_world->barrier_cond);
- xbt_free(smpi_mpi_global->mpi_comm_world->processes);
- xbt_free(smpi_mpi_global->mpi_comm_world);
+/**
+ * tell the MPI rank of the calling process (from its SIMIX process id)
+ **/
+int smpi_mpi_comm_rank(smpi_mpi_communicator_t comm)
+{
+ return comm->index_to_rank_map[smpi_process_index()];
+}
- xbt_free(smpi_mpi_global->mpi_byte);
- xbt_free(smpi_mpi_global->mpi_int);
- xbt_free(smpi_mpi_global->mpi_double);
+void smpi_process_init(int *argc, char ***argv)
+{
+ smpi_process_data_t pdata;
+
+ // initialize some local variables
+
+ pdata = xbt_new(s_smpi_process_data_t, 1);
+ SIMIX_process_set_data(SIMIX_process_self(), pdata);
+
+ /* get rank from command line, and remove it from argv */
+ pdata->index = atoi((*argv)[1]);
+ DEBUG1("I'm rank <%d>", pdata->index);
+ if (*argc > 2) {
+ memmove((*argv)[1], (*argv)[2], sizeof(char *) * (*argc - 2));
+ (*argv)[(*argc) - 1] = NULL;
+ }
+ (*argc)--;
+
+ pdata->mutex = SIMIX_mutex_init();
+ pdata->cond = SIMIX_cond_init();
+ pdata->finalize = 0;
+
+ pdata->pending_recv_request_queue = xbt_fifo_new();
+ pdata->pending_send_request_queue = xbt_fifo_new();
+ pdata->received_message_queue = xbt_fifo_new();
+
+ pdata->main = SIMIX_process_self();
+ pdata->sender = SIMIX_process_create("smpi_sender",
+ smpi_sender, pdata,
+ SIMIX_host_get_name(SIMIX_host_self()),
+ 0, NULL,
+ /*props */ NULL);
+ pdata->receiver = SIMIX_process_create("smpi_receiver",
+ smpi_receiver, pdata,
+ SIMIX_host_get_name(SIMIX_host_self
+ ()), 0, NULL,
+ /*props */ NULL);
+
+ smpi_global->main_processes[pdata->index] = SIMIX_process_self();
+ return;
+}
- xbt_free(smpi_mpi_global->mpi_land);
- xbt_free(smpi_mpi_global->mpi_sum);
+void smpi_process_finalize()
+{
+ smpi_process_data_t pdata = SIMIX_process_get_data(SIMIX_process_self());
+
+ pdata->finalize = 2; /* Tell sender and receiver to quit */
+ SIMIX_process_resume(pdata->sender);
+ SIMIX_process_resume(pdata->receiver);
+ while (pdata->finalize > 0) { /* wait until it's done */
+ SIMIX_cond_wait(pdata->cond, pdata->mutex);
+ }
+
+ SIMIX_mutex_destroy(pdata->mutex);
+ SIMIX_cond_destroy(pdata->cond);
+ xbt_fifo_free(pdata->pending_recv_request_queue);
+ xbt_fifo_free(pdata->pending_send_request_queue);
+ xbt_fifo_free(pdata->received_message_queue);
+ xbt_free(pdata);
+}
- xbt_free(smpi_mpi_global);
- }
+/*int smpi_mpi_barrier(smpi_mpi_communicator_t comm)
+{
+ SIMIX_mutex_lock(comm->barrier_mutex);
+ ++comm->barrier_count;
+ if (comm->barrier_count > comm->size) { // only happens on second barrier...
+ comm->barrier_count = 0;
+ } else if (comm->barrier_count == comm->size) {
+ SIMIX_cond_broadcast(comm->barrier_cond);
+ }
+ while (comm->barrier_count < comm->size) {
+ SIMIX_cond_wait(comm->barrier_cond, comm->barrier_mutex);
+ }
+ SIMIX_mutex_unlock(comm->barrier_mutex);
+
+ return MPI_SUCCESS;
}
+*/
-void smpi_barrier(smpi_mpi_communicator_t comm)
+int smpi_mpi_isend(smpi_mpi_request_t request)
{
+ smpi_process_data_t pdata = SIMIX_process_get_data(SIMIX_process_self());
+ int retval = MPI_SUCCESS;
- SIMIX_mutex_lock(comm->barrier_mutex);
- if(++comm->barrier_count < comm->size) {
- SIMIX_cond_wait(comm->barrier_cond, comm->barrier_mutex);
- } else {
- comm->barrier_count = 0;
- SIMIX_cond_broadcast(comm->barrier_cond);
- }
- SIMIX_mutex_unlock(comm->barrier_mutex);
+ if (NULL == request) {
+ retval = MPI_ERR_INTERN;
+ } else {
+ xbt_fifo_push(pdata->pending_send_request_queue, request);
+ SIMIX_process_resume(pdata->sender);
+ }
- return;
-}
-
-int smpi_create_request(void *buf, int count, smpi_mpi_datatype_t datatype,
- int src, int dst, int tag, smpi_mpi_communicator_t comm, smpi_mpi_request_t *request)
-{
- int retval = MPI_SUCCESS;
-
- *request = NULL;
-
- if (0 > count) {
- retval = MPI_ERR_COUNT;
- } else if (NULL == buf) {
- retval = MPI_ERR_INTERN;
- } else if (NULL == datatype) {
- retval = MPI_ERR_TYPE;
- } else if (NULL == comm) {
- retval = MPI_ERR_COMM;
- } else if (MPI_ANY_SOURCE != src && (0 > src || comm->size <= src)) {
- retval = MPI_ERR_RANK;
- } else if (0 > dst || comm->size <= dst) {
- retval = MPI_ERR_RANK;
- } else if (0 > tag) {
- retval = MPI_ERR_TAG;
- } else {
- *request = xbt_mallocator_get(smpi_global->request_mallocator);
- (*request)->comm = comm;
- (*request)->src = src;
- (*request)->dst = dst;
- (*request)->tag = tag;
- (*request)->buf = buf;
- (*request)->count = count;
- (*request)->datatype = datatype;
- }
- return retval;
+ return retval;
}
-int smpi_isend(smpi_mpi_request_t request)
+int smpi_mpi_irecv(smpi_mpi_request_t request)
{
- int retval = MPI_SUCCESS;
- int rank = smpi_mpi_comm_rank_self(smpi_mpi_global->mpi_comm_world);
+ int retval = MPI_SUCCESS;
+ smpi_process_data_t pdata = SIMIX_process_get_data(SIMIX_process_self());
- if (NULL != request) {
- SIMIX_mutex_lock(smpi_global->pending_send_request_queues_mutexes[rank]);
- xbt_fifo_push(smpi_global->pending_send_request_queues[rank], request);
- SIMIX_mutex_unlock(smpi_global->pending_send_request_queues_mutexes[rank]);
- }
+ if (NULL == request) {
+ retval = MPI_ERR_INTERN;
+ } else {
+ xbt_fifo_push(pdata->pending_recv_request_queue, request);
- if (SIMIX_process_is_suspended(smpi_global->sender_processes[rank])) {
- SIMIX_process_resume(smpi_global->sender_processes[rank]);
- }
+ if (SIMIX_process_is_suspended(pdata->receiver)) {
+ SIMIX_process_resume(pdata->receiver);
+ }
+ }
- return retval;
+ return retval;
}
-int smpi_irecv(smpi_mpi_request_t request)
-{
- int retval = MPI_SUCCESS;
- int rank = smpi_mpi_comm_rank_self(smpi_mpi_global->mpi_comm_world);
+void print_req( smpi_mpi_request_t r );
+void print_req( smpi_mpi_request_t r ) {
+ fprintf(stderr,"***req %p-> src=%d dst=%d tag=%d completed=0x%x consumed=0x%x\n",r,r->src,r->dst,r->tag,r->completed,r->consumed);
+}
- if (NULL != request) {
- SIMIX_mutex_lock(smpi_global->pending_recv_request_queues_mutexes[rank]);
- xbt_fifo_push(smpi_global->pending_recv_request_queues[rank], request);
- SIMIX_mutex_unlock(smpi_global->pending_recv_request_queues_mutexes[rank]);
- }
- if (SIMIX_process_is_suspended(smpi_global->receiver_processes[rank])) {
- SIMIX_process_resume(smpi_global->receiver_processes[rank]);
- }
+/**
+ * wait and friends ...
+ **/
+int smpi_mpi_wait(smpi_mpi_request_t request, smpi_mpi_status_t * status)
+{
+ int retval = MPI_SUCCESS;
+
+ if (NULL == request) {
+ retval = MPI_ERR_INTERN;
+ } else {
+
+ DEBUG3("entered smpi_mpi_wait() for req_src=%d,req_dst=%d,req_tag=%d",
+ request->src,request->dst,request->tag);
+ SIMIX_mutex_lock(request->mutex);
+//#define DEBUG_STEPH
+#ifdef DEBUG_STEPH
+ print_req( request ); //@@
+#endif
+ while (!request->completed) {
+ SIMIX_cond_wait(request->cond, request->mutex);
+ }
+ if (NULL != status) {
+ status->MPI_SOURCE = request->src;
+ status->MPI_TAG = request->tag;
+ status->MPI_ERROR = MPI_SUCCESS;
+ }
+ SIMIX_mutex_unlock(request->mutex);
+ }
+
+ return retval;
+}
- return retval;
+/**
+ * waitall
+ **/
+int smpi_mpi_waitall(int count, smpi_mpi_request_t requests[],
+ smpi_mpi_status_t status[])
+{
+ int cpt;
+ int index;
+ int retval;
+ smpi_mpi_status_t stat;
+
+ for (cpt = 0; cpt < count; cpt++) {
+ retval = smpi_mpi_waitany(count, requests, &index, &stat);
+ if (retval != MPI_SUCCESS)
+ return retval;
+ if (MPI_STATUS_IGNORE != status)
+ memcpy(&(status[index]), &stat, sizeof(stat));
+ }
+ return MPI_SUCCESS;
}
-int smpi_wait(smpi_mpi_request_t request, smpi_mpi_status_t *status)
+/**
+ * waitany
+ **/
+int smpi_mpi_waitany(int count, smpi_mpi_request_t * requests, int *index,
+ smpi_mpi_status_t * status)
{
- if (NULL != request) {
- SIMIX_mutex_lock(request->mutex);
- if (!request->completed) {
- SIMIX_cond_wait(request->cond, request->mutex);
- }
- if (NULL != status) {
- status->MPI_SOURCE = request->src;
- }
- SIMIX_mutex_unlock(request->mutex);
- }
-
- return MPI_SUCCESS;
+ int cpt;
+
+ DEBUG0("entering smpi_wait_any() ...");
+ *index = MPI_UNDEFINED;
+ if (NULL == requests) {
+ return MPI_ERR_INTERN;
+ }
+ /* First check if one of them is already done */
+ for (cpt = 0; cpt < count; cpt++) {
+ DEBUG2(" exam req[%d] of msg from <%d>",cpt,requests[cpt]->src);
+ if (requests[cpt]->completed && !requests[cpt]->consumed) { /* got ya */
+ DEBUG2("smpi_wait_any() found match req[%d] of msg from <%d>",cpt,requests[cpt]->src);
+ *index = cpt;
+ goto found_request;
+ }
+ }
+ /* If none found, block */
+ /* FIXME: should use a SIMIX_cond_waitany, when implemented. For now, block on the first one */
+ while (1) {
+ for (cpt = 0; cpt < count; cpt++) {
+
+#ifdef DEBUG_STEPH
+ print_req( requests[cpt] );
+#endif
+ if (!requests[cpt]->completed) { /* this one is not done, wait on it */
+ DEBUG3("smpi_waitany() blocked waiting a msg <%d> -> <%d>, tag=%d",requests[cpt]->src,requests[cpt]->dst,requests[cpt]->tag);
+ while (!requests[cpt]->completed)
+ SIMIX_cond_wait(requests[cpt]->cond, requests[cpt]->mutex);
+
+ *index = cpt;
+ goto found_request;
+ }
+ }
+ if (cpt == count) /* they are all done. Damn user */
+ return MPI_ERR_REQUEST;
+ }
+
+found_request:
+#ifdef DEBUG_STEPH
+ print_req( requests[cpt] );
+#endif
+ requests[*index]->consumed = 1;
+#ifdef DEBUG_STEPH
+ print_req( requests[cpt] );
+#endif
+ DEBUG2("smpi_waitany() request %p unblocked ... mark *req[%d]->consumed",requests[*index],cpt);
+ if (NULL != status) {
+ status->MPI_SOURCE = requests[*index]->src;
+ status->MPI_TAG = requests[*index]->tag;
+ status->MPI_ERROR = MPI_SUCCESS;
+ }
+ return MPI_SUCCESS;
+
}