X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/5f7e3ee3f051a31e1568c69456e83f20ff69e69f..394a9cd893e93ee04bf4a8f6ff4ad5a8697a0e82:/src/smpi/smpi_base.c

diff --git a/src/smpi/smpi_base.c b/src/smpi/smpi_base.c
index 62834b624b..05a391a4b2 100644
--- a/src/smpi/smpi_base.c
+++ b/src/smpi/smpi_base.c
@@ -1,242 +1,536 @@
 #include "private.h"
+#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);
+
+void smpi_process_init(int* argc, char*** argv) {
+  int index;
+  smpi_process_data_t data;
+  smx_process_t proc;
+
+  proc = SIMIX_process_self();
+  index = atoi((*argv)[1]);
+  data = smpi_process_remote_data(index);
+  SIMIX_process_set_data(proc, data);
+  if (*argc > 2) {
+    free((*argv)[1]);
+    memmove(&(*argv)[1], &(*argv)[2], sizeof(char *) * (*argc - 2));
+    (*argv)[(*argc) - 1] = NULL;
+  }
+  (*argc)--;
+  DEBUG2("<%d> New process in the game: %p", index, proc);
+}
+
+void smpi_process_destroy(void) {
+  int index = smpi_process_index();
+
+  DEBUG1("<%d> Process left the game", index);
+}
+
+/* MPI Low level calls */
+MPI_Request smpi_mpi_isend(void* buf, int count, MPI_Datatype datatype, int dst, int tag, MPI_Comm comm) {
+  MPI_Request request;
+
+  request = xbt_new(s_smpi_mpi_request_t, 1);
+  request->comm = comm;
+  request->src = smpi_comm_rank(comm);
+  request->dst = dst;
+  request->tag = tag;
+  request->size = smpi_datatype_size(datatype) * count;
+  request->complete = 0;
+  request->data = request;
+  smpi_process_post_send(comm, request);
+  request->pair = SIMIX_network_isend(request->rdv, request->size, -1.0, buf, request->size, NULL);
+  return request;
+}
+
+MPI_Request smpi_mpi_irecv(void* buf, int count, MPI_Datatype datatype, int src, int tag, MPI_Comm comm) {
+  MPI_Request request;
+
+  request = xbt_new(s_smpi_mpi_request_t, 1);
+  request->comm = comm;
+  request->src = src;
+  request->dst = smpi_comm_rank(comm);
+  request->tag = tag;
+  request->size = smpi_datatype_size(datatype) * count;
+  request->complete = 0;
+  request->data = MPI_REQUEST_NULL;
+  smpi_process_post_recv(request);
+  request->pair = SIMIX_network_irecv(request->rdv, buf, &request->size);
+  return request;
+}
 
-smpi_mpi_global_t smpi_mpi_global = NULL;
+void smpi_mpi_recv(void* buf, int count, MPI_Datatype datatype, int src, int tag, MPI_Comm comm, MPI_Status* status) {
+  MPI_Request request;
 
-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 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 *a, void *b, int *length, MPI_Datatype *datatype);
-
-void smpi_mpi_sum_func(void *a, void *b, int *length, MPI_Datatype *datatype)
-{
-	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];
-		}
-	}
-}
-
-int inline smpi_mpi_comm_rank(smpi_mpi_communicator_t comm)
-{
-	return comm->index_to_rank_map[smpi_host_index()];
-}
-
-void smpi_mpi_init()
-{
-	smx_host_t host;
-	smx_host_t *hosts;
-	int host_count;
-	int i;
-	smpi_host_data_t hdata;
-
-	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
-	host       = SIMIX_host_self();
-	hosts      = SIMIX_host_get_table();
-	host_count = SIMIX_host_get_number();
-
-	hdata      = xbt_new(s_smpi_host_data_t, 1);
-
-	for (i = 0; i < host_count && host != hosts[i]; i ++);
-
-	hdata->index = i;
-
-	SIMIX_host_set_data(host, hdata);
-
-	// node 0 sets the globals
-	if (0 == i) {
-
-		smpi_global->hosts                              = hosts;
-		smpi_global->host_count                         = host_count;
+  request = smpi_mpi_irecv(buf, count, datatype, src, tag, comm);
+  smpi_mpi_wait(&request, status);
+}
 
-		smpi_mpi_global                                 = xbt_new(s_smpi_mpi_global_t, 1);
+void smpi_mpi_send(void* buf, int count, MPI_Datatype datatype, int src, int tag, MPI_Comm comm) {
+  MPI_Request request;
 
-		// global communicator
-		smpi_mpi_global->mpi_comm_world                 = xbt_new(s_smpi_mpi_communicator_t, 1);
-		smpi_mpi_global->mpi_comm_world->size           = host_count;
-		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();
-		smpi_mpi_global->mpi_comm_world->rank_to_index_map = xbt_new(int, host_count);
-		smpi_mpi_global->mpi_comm_world->index_to_rank_map = xbt_new(int, host_count);
-		for (i = 0; i < host_count; i++) {
-			smpi_mpi_global->mpi_comm_world->rank_to_index_map[i] = i;
-			smpi_mpi_global->mpi_comm_world->index_to_rank_map[i] = i;
-		}
+  request = smpi_mpi_isend(buf, count, datatype, src, tag, comm);
+  smpi_mpi_wait(&request, MPI_STATUS_IGNORE);
+}
 
-		// 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);
+void smpi_mpi_sendrecv(void* sendbuf, int sendcount, MPI_Datatype sendtype, int dst, int sendtag, void* recvbuf, int recvcount, MPI_Datatype recvtype, int src, int recvtag, MPI_Comm comm, MPI_Status* status) {
+  MPI_Request requests[2];
+  MPI_Status stats[2];
+
+  requests[0] = smpi_mpi_isend(sendbuf, sendcount, sendtype, dst, sendtag, comm);
+  requests[1] = smpi_mpi_irecv(recvbuf, recvcount, recvtype, src, recvtag, comm);
+  smpi_mpi_waitall(2, requests, stats);
+  if(status != MPI_STATUS_IGNORE) {
+    // Copy receive status
+    memcpy(status, &stats[1], sizeof(MPI_Status));
+  }
+}
 
-		// 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;
+static void finish_wait(MPI_Request* request, MPI_Status* status) {
+  MPI_Request data = (*request)->data;
+
+  xbt_assert0(data != MPI_REQUEST_NULL, "Erroneous situation");
+  if(status != MPI_STATUS_IGNORE) {
+    status->MPI_SOURCE = (*request)->src;
+    status->MPI_TAG = (*request)->tag;
+    status->MPI_ERROR = MPI_SUCCESS;
+  }
+  DEBUG3("finishing wait for %p [data = %p, complete = %d]", *request, data, data->complete);
+  // data == *request if sender is first to finish its wait
+  // data != *request if receiver is first to finish its wait
+  if(data->complete == 0) {
+    // first arrives here
+    data->complete = 1;
+    if(data != *request) {
+      // receveiver cleans its part
+      xbt_free(*request);
+    }
+  } else {
+    // second arrives here
+    if(data != *request) {
+      // receiver cleans everything
+      xbt_free(data);
+    }
+    SIMIX_rdv_destroy((*request)->rdv);
+    xbt_free(*request);
+  }
+  *request = MPI_REQUEST_NULL;
+}
 
-		// 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);
+int smpi_mpi_test(MPI_Request* request, MPI_Status* status) {
+  MPI_Request data = (*request)->data;
+  int flag = data && data->complete == 1;
 
-	} else {
+  if(flag) {
+    SIMIX_communication_destroy((*request)->pair);
+    finish_wait(request, status);
+  }
+  return flag;
+}
 
-		// 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);
-
-	}
-
-	// 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 * host_count) {
-		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);
+int smpi_mpi_testany(int count, MPI_Request requests[], int* index, MPI_Status* status) {
+  MPI_Request data;
+  int i, flag;
+
+  *index = MPI_UNDEFINED;
+  flag = 0;
+  for(i = 0; i < count; i++) {
+    if(requests[i] != MPI_REQUEST_NULL) {
+      data = requests[i]->data;
+      if(data != MPI_REQUEST_NULL && data->complete == 1) {
+        SIMIX_communication_destroy(requests[i]->pair);
+        finish_wait(&requests[i], status);
+        *index = i;
+        flag = 1;
+        break;
+      }
+    }
+  }
+  return flag;
+}
 
-	return;
+void smpi_mpi_wait(MPI_Request* request, MPI_Status* status) {
+  MPI_Request data = (*request)->data;
+
+  DEBUG6("wait for request %p (%p: %p) [src = %d, dst = %d, tag = %d]",
+         *request, (*request)->pair, data, (*request)->src, (*request)->dst, (*request)->tag);
+  // data is null if receiver waits before sender enters the rdv
+  if(data == MPI_REQUEST_NULL || data->complete == 0) {
+    SIMIX_network_wait((*request)->pair, -1.0);
+  } else {
+    SIMIX_communication_destroy((*request)->pair);
+  }
+  finish_wait(request, status);
 }
 
-void smpi_mpi_finalize()
-{
-	int i;
+int smpi_mpi_waitany(int count, MPI_Request requests[], MPI_Status* status) {
+  xbt_dynar_t comms;
+  MPI_Request data;
+  int i, size, index;
+  int* map;
+
+  index = MPI_UNDEFINED;
+  if(count > 0) {
+    // First check for already completed requests
+    for(i = 0; i < count; i++) {
+      if(requests[i] != MPI_REQUEST_NULL) {
+        data = requests[i]->data;
+        if(data != MPI_REQUEST_NULL && data->complete == 1) {
+          index = i;
+          SIMIX_communication_destroy(requests[index]->pair); // always succeeds (but cleans the simix layer)
+          break;
+        }
+      }
+    }
+    if(index == MPI_UNDEFINED) {
+      // Otherwise, wait for a request to complete
+      comms = xbt_dynar_new(sizeof(smx_comm_t), NULL);
+      map = xbt_new(int, count);
+      size = 0;
+      DEBUG0("Wait for one of");
+      for(i = 0; i < count; i++) {
+        if(requests[i] != MPI_REQUEST_NULL && requests[i]->complete == 0) {
+         DEBUG4("   request %p [src = %d, dst = %d, tag = %d]",
+                requests[i], requests[i]->src, requests[i]->dst, requests[i]->tag);
+          xbt_dynar_push(comms, &requests[i]->pair);
+          map[size] = i;
+          size++;
+        }
+      }
+      if(size > 0) {
+        index = SIMIX_network_waitany(comms);
+        index = map[index];
+      }
+      xbt_free(map);
+      xbt_dynar_free_container(&comms);
+    }
+    if(index != MPI_UNDEFINED) {
+      finish_wait(&requests[index], status);
+    }
+  }
+  return index;
+}
 
-	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_global->host_count; 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);
-
-		xbt_free(smpi_mpi_global->mpi_byte);
-		xbt_free(smpi_mpi_global->mpi_int);
-		xbt_free(smpi_mpi_global->mpi_double);
-
-		xbt_free(smpi_mpi_global->mpi_land);
-		xbt_free(smpi_mpi_global->mpi_sum);
-
-		xbt_free(smpi_mpi_global);
-
-	}
-
-}
-
-int smpi_mpi_barrier(smpi_mpi_communicator_t comm)
-{
-
-	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);
-
-	return MPI_SUCCESS;
-}
-
-int smpi_mpi_isend(smpi_mpi_request_t request)
-{
-	int retval = MPI_SUCCESS;
-	int index  = smpi_host_index();
-
-	if (NULL == request) {
-		retval = MPI_ERR_INTERN;
-	} else {
-		SIMIX_mutex_lock(smpi_global->pending_send_request_queues_mutexes[index]);
-		xbt_fifo_push(smpi_global->pending_send_request_queues[index], request);
-		SIMIX_mutex_unlock(smpi_global->pending_send_request_queues_mutexes[index]);
-
-		if (SIMIX_process_is_suspended(smpi_global->sender_processes[index])) {
-			SIMIX_process_resume(smpi_global->sender_processes[index]);
-		}
-	}
-
-	return retval;
+void smpi_mpi_waitall(int count, MPI_Request requests[],  MPI_Status status[]) {
+  int index;
+  MPI_Status stat;
+
+  while(count > 0) {
+    index = smpi_mpi_waitany(count, requests, &stat);
+    if(index == MPI_UNDEFINED) {
+      break;
+    }
+    if(status != MPI_STATUS_IGNORE) {
+      memcpy(&status[index], &stat, sizeof(stat));
+    }
+    // Move the last request to the found position
+    requests[index] = requests[count - 1];
+    requests[count - 1] = MPI_REQUEST_NULL;
+    count--;
+  }
 }
 
-int smpi_mpi_irecv(smpi_mpi_request_t request)
-{
-	int retval = MPI_SUCCESS;
-	int index = smpi_host_index();
-
-	if (NULL == request) {
-		retval = MPI_ERR_INTERN;
-	} else {
-		SIMIX_mutex_lock(smpi_global->pending_recv_request_queues_mutexes[index]);
-		xbt_fifo_push(smpi_global->pending_recv_request_queues[index], request);
-		SIMIX_mutex_unlock(smpi_global->pending_recv_request_queues_mutexes[index]);
-
-		if (SIMIX_process_is_suspended(smpi_global->receiver_processes[index])) {
-			SIMIX_process_resume(smpi_global->receiver_processes[index]);
-		}
-	}
+int smpi_mpi_waitsome(int incount, MPI_Request requests[], int* indices, MPI_Status status[]) {
+  MPI_Request data;
+  int i, count;
+
+  count = 0;
+  for(i = 0; i < incount; i++) {
+    if(requests[i] != MPI_REQUEST_NULL) {
+      data = requests[i]->data;
+      if(data != MPI_REQUEST_NULL && data->complete == 1) {
+        SIMIX_communication_destroy(requests[i]->pair);
+        finish_wait(&requests[i], status != MPI_STATUS_IGNORE ? &status[i] : MPI_STATUS_IGNORE);
+        indices[count] = i;
+        count++;
+      }
+    }
+  }
+  return count;
+}
 
-	return retval;
+void smpi_mpi_bcast(void* buf, int count, MPI_Datatype datatype, int root, MPI_Comm comm) {
+  // arity=2: a binary tree, arity=4 seem to be a good setting (see P2P-MPI))
+  nary_tree_bcast(buf, count, datatype, root, comm, 4);
 }
 
-int smpi_mpi_wait(smpi_mpi_request_t request, smpi_mpi_status_t *status)
-{
-	int retval = MPI_SUCCESS;
+void smpi_mpi_barrier(MPI_Comm comm) {
+  // arity=2: a binary tree, arity=4 seem to be a good setting (see P2P-MPI))
+  nary_tree_barrier(comm, 4);
+}
+
+void smpi_mpi_gather(void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount, MPI_Datatype recvtype, int root, MPI_Comm comm) {
+  int system_tag = 666;
+  int rank, size, src, index, sendsize, recvsize;
+  MPI_Request* requests;
+
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  if(rank != root) {
+    // Send buffer to root
+    smpi_mpi_send(sendbuf, sendcount, sendtype, root, system_tag, comm);
+  } else {
+    sendsize = smpi_datatype_size(sendtype);
+    recvsize = smpi_datatype_size(recvtype);
+    // Local copy from root
+    memcpy(&((char*)recvbuf)[root * recvcount * recvsize], sendbuf, sendcount * sendsize * sizeof(char));
+    // Receive buffers from senders
+    requests = xbt_new(MPI_Request, size - 1);
+    index = 0;
+    for(src = 0; src < size; src++) {
+      if(src != root) {
+        requests[index] = smpi_mpi_irecv(&((char*)recvbuf)[src * recvcount * recvsize], recvcount, recvtype, src, system_tag, comm);
+        index++;
+      }
+    }
+    // Wait for completion of irecv's.
+    smpi_mpi_waitall(size - 1, requests, MPI_STATUS_IGNORE);
+    xbt_free(requests);
+  }
+}
+
+void smpi_mpi_gatherv(void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int* recvcounts, int* displs, MPI_Datatype recvtype, int root, MPI_Comm comm) {
+  int system_tag = 666;
+  int rank, size, src, index, sendsize;
+  MPI_Request* requests;
+
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  if(rank != root) {
+    // Send buffer to root
+    smpi_mpi_send(sendbuf, sendcount, sendtype, root, system_tag, comm);
+  } else {
+    sendsize = smpi_datatype_size(sendtype);
+    // Local copy from root
+    memcpy(&((char*)recvbuf)[displs[root]], sendbuf, sendcount * sendsize * sizeof(char));
+    // Receive buffers from senders
+    requests = xbt_new(MPI_Request, size - 1);
+    index = 0;
+    for(src = 0; src < size; src++) {
+      if(src != root) {
+        requests[index] = smpi_mpi_irecv(&((char*)recvbuf)[displs[src]], recvcounts[src], recvtype, src, system_tag, comm);
+        index++;
+      }
+    }
+    // Wait for completion of irecv's.
+    smpi_mpi_waitall(size - 1, requests, MPI_STATUS_IGNORE);
+    xbt_free(requests);
+  }
+}
+
+void smpi_mpi_allgather(void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount, MPI_Datatype recvtype, MPI_Comm comm) {
+  int system_tag = 666;
+  int rank, size, other, index, sendsize, recvsize;
+  MPI_Request* requests;
+
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  sendsize = smpi_datatype_size(sendtype);
+  recvsize = smpi_datatype_size(recvtype);
+  // Local copy from self
+  memcpy(&((char*)recvbuf)[rank * recvcount * recvsize], sendbuf, sendcount * sendsize * sizeof(char));
+  // Send/Recv buffers to/from others;
+  requests = xbt_new(MPI_Request, 2 * (size - 1));
+  index = 0;
+  for(other = 0; other < size; other++) {
+    if(other != rank) {
+      requests[index] = smpi_mpi_isend(sendbuf, sendcount, sendtype, other, system_tag, comm);
+      index++;
+      requests[index] = smpi_mpi_irecv(&((char*)recvbuf)[other * recvcount * recvsize], recvcount, recvtype, other, system_tag, comm);
+      index++;
+    }
+  }
+  // Wait for completion of all comms.
+  smpi_mpi_waitall(2 * (size - 1), requests, MPI_STATUS_IGNORE);
+  xbt_free(requests);
+}
+
+void smpi_mpi_allgatherv(void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int* recvcounts, int* displs, MPI_Datatype recvtype, MPI_Comm comm) {
+  int system_tag = 666;
+  int rank, size, other, index, sendsize, recvsize;
+  MPI_Request* requests;
+
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  sendsize = smpi_datatype_size(sendtype);
+  recvsize = smpi_datatype_size(recvtype);
+  // Local copy from self
+  memcpy(&((char*)recvbuf)[displs[rank]], sendbuf, sendcount * sendsize * sizeof(char));
+  // Send buffers to others;
+  requests = xbt_new(MPI_Request, 2 * (size - 1));
+  index = 0;
+  for(other = 0; other < size; other++) {
+    if(other != rank) {
+      requests[index] = smpi_mpi_isend(sendbuf, sendcount, sendtype, other, system_tag, comm);
+      index++;
+      requests[index] = smpi_mpi_irecv(&((char*)recvbuf)[displs[other]], recvcounts[other], recvtype, other, system_tag, comm);
+      index++;
+    }
+  }
+  // Wait for completion of all comms.
+  smpi_mpi_waitall(2 * (size - 1), requests, MPI_STATUS_IGNORE);
+  xbt_free(requests);
+}
+
+void smpi_mpi_scatter(void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int recvcount, MPI_Datatype recvtype, int root, MPI_Comm comm) {
+  int system_tag = 666;
+  int rank, size, dst, index, sendsize, recvsize;
+  MPI_Request* requests;
+
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  if(rank != root) {
+    // Recv buffer from root
+    smpi_mpi_recv(recvbuf, recvcount, recvtype, root, system_tag, comm, MPI_STATUS_IGNORE);
+  } else {
+    sendsize = smpi_datatype_size(sendtype);
+    recvsize = smpi_datatype_size(recvtype);
+    // Local copy from root
+    memcpy(recvbuf, &((char*)sendbuf)[root * sendcount * sendsize], recvcount * recvsize * sizeof(char));
+    // Send buffers to receivers
+    requests = xbt_new(MPI_Request, size - 1);
+    index = 0;
+    for(dst = 0; dst < size; dst++) {
+      if(dst != root) {
+        requests[index] = smpi_mpi_isend(&((char*)sendbuf)[dst * sendcount * sendsize], sendcount, sendtype, dst, system_tag, comm);
+        index++;
+      }
+    }
+    // Wait for completion of isend's.
+    smpi_mpi_waitall(size - 1, requests, MPI_STATUS_IGNORE);
+    xbt_free(requests);
+  }
+}
+
+void smpi_mpi_scatterv(void* sendbuf, int* sendcounts, int* displs, MPI_Datatype sendtype, void* recvbuf, int recvcount, MPI_Datatype recvtype, int root, MPI_Comm comm) {
+  int system_tag = 666;
+  int rank, size, dst, index, sendsize, recvsize;
+  MPI_Request* requests;
+
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  if(rank != root) {
+    // Recv buffer from root
+    smpi_mpi_recv(recvbuf, recvcount, recvtype, root, system_tag, comm, MPI_STATUS_IGNORE);
+  } else {
+    sendsize = smpi_datatype_size(sendtype);
+    recvsize = smpi_datatype_size(recvtype);
+    // Local copy from root
+    memcpy(recvbuf, &((char*)sendbuf)[displs[root]], recvcount * recvsize * sizeof(char));
+    // Send buffers to receivers
+    requests = xbt_new(MPI_Request, size - 1);
+    index = 0;
+    for(dst = 0; dst < size; dst++) {
+      if(dst != root) {
+        requests[index] = smpi_mpi_isend(&((char*)sendbuf)[displs[dst]], sendcounts[dst], sendtype, dst, system_tag, comm);
+        index++;
+      }
+    }
+    // Wait for completion of isend's.
+    smpi_mpi_waitall(size - 1, requests, MPI_STATUS_IGNORE);
+    xbt_free(requests);
+  }
+}
+
+void smpi_mpi_reduce(void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype, MPI_Op op, int root, MPI_Comm comm) {
+  int system_tag = 666;
+  int rank, size, src, index, datasize;
+  MPI_Request* requests;
+  void** tmpbufs;
+ 
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  if(rank != root) {
+    // Send buffer to root
+    smpi_mpi_send(sendbuf, count, datatype, root, system_tag, comm);
+  } else {
+    datasize = smpi_datatype_size(datatype);
+    // Local copy from root
+    memcpy(recvbuf, sendbuf, count * datasize * sizeof(char)); 
+    // Receive buffers from senders
+    //TODO: make a MPI_barrier here ?
+    requests = xbt_new(MPI_Request, size - 1);
+    tmpbufs = xbt_new(void*, size - 1);
+    index = 0;
+    for(src = 0; src < size; src++) {
+      if(src != root) {
+        tmpbufs[index] = xbt_malloc(count * datasize);
+        requests[index] = smpi_mpi_irecv(tmpbufs[index], count, datatype, src, system_tag, comm);
+        index++;
+      }
+    }
+    // Wait for completion of irecv's.
+    for(src = 0; src < size - 1; src++) {
+      index = smpi_mpi_waitany(size - 1, requests, MPI_STATUS_IGNORE);
+      if(index == MPI_UNDEFINED) {
+        break;
+      }
+      smpi_op_apply(op, tmpbufs[index], recvbuf, &count, &datatype);
+    }
+    for(index = 0; index < size - 1; index++) {
+      xbt_free(tmpbufs[index]);
+    }
+    xbt_free(tmpbufs);
+    xbt_free(requests);
+  }
+}
 
-	if (NULL == request) {
-		retval = MPI_ERR_INTERN;
-	} else {
-		SIMIX_mutex_lock(request->mutex);
-		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;
+void smpi_mpi_allreduce(void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype, MPI_Op op, MPI_Comm comm) {
+  smpi_mpi_reduce(sendbuf, recvbuf, count, datatype, op, 0, comm);
+  smpi_mpi_bcast(recvbuf, count, datatype, 0, comm);
+
+/*
+FIXME: buggy implementation
+
+  int system_tag = 666;
+  int rank, size, other, index, datasize;
+  MPI_Request* requests;
+  void** tmpbufs;
+ 
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+  datasize = smpi_datatype_size(datatype);
+  // Local copy from self
+  memcpy(recvbuf, sendbuf, count * datasize * sizeof(char)); 
+  // Send/Recv buffers to/from others;
+  //TODO: make a MPI_barrier here ?
+  requests = xbt_new(MPI_Request, 2 * (size - 1));
+  tmpbufs = xbt_new(void*, size - 1);
+  index = 0;
+  for(other = 0; other < size; other++) {
+    if(other != rank) {
+      tmpbufs[index / 2] = xbt_malloc(count * datasize);
+      requests[index] = smpi_mpi_isend(sendbuf, count, datatype, other, system_tag, comm);
+      requests[index + 1] = smpi_mpi_irecv(tmpbufs[index / 2], count, datatype, other, system_tag, comm);
+      index += 2;
+    }
+  }
+  // Wait for completion of all comms.
+  for(other = 0; other < 2 * (size - 1); other++) {
+    index = smpi_mpi_waitany(size - 1, requests, MPI_STATUS_IGNORE);
+    if(index == MPI_UNDEFINED) {
+      break;
+    }
+    if((index & 1) == 1) {
+      // Request is odd: it's a irecv
+      smpi_op_apply(op, tmpbufs[index / 2], recvbuf, &count, &datatype);
+    }
+  }
+  for(index = 0; index < size - 1; index++) {
+    xbt_free(tmpbufs[index]);
+  }
+  xbt_free(tmpbufs);
+  xbt_free(requests);
+*/
 }