X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/a7740c25f68f21ce361c63ab639a7fe3cd18042b..4fa2931658e07433d8bd09d002697114b1c67d9b:/src/smpi/smpi_mpi.c

diff --git a/src/smpi/smpi_mpi.c b/src/smpi/smpi_mpi.c
index 1d4e1ca44d..6b767a95c3 100644
--- a/src/smpi/smpi_mpi.c
+++ b/src/smpi/smpi_mpi.c
@@ -1,311 +1,621 @@
+
+
 #include "private.h"
+#include "smpi_coll_private.h"
 
-int MPI_Init(int *argc, char ***argv)
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_mpi, smpi,
+                                "Logging specific to SMPI (mpi)");
+
+int SMPI_MPI_Init(int *argc, char ***argv)
 {
-	smpi_mpi_init();
-	smpi_bench_begin();
-	return MPI_SUCCESS;
+  smpi_process_init(argc, argv);
+  smpi_bench_begin();
+  return MPI_SUCCESS;
 }
 
-int MPI_Finalize()
+int SMPI_MPI_Finalize()
 {
-	smpi_bench_end();
-	smpi_mpi_finalize();
-	return MPI_SUCCESS;
+  smpi_bench_end();
+  smpi_process_finalize();
+  return MPI_SUCCESS;
 }
 
 // right now this just exits the current node, should send abort signal to all
-// hosts in the communicator;
-int MPI_Abort(MPI_Comm comm, int errorcode)
+// hosts in the communicator (TODO)
+int SMPI_MPI_Abort(MPI_Comm comm, int errorcode)
 {
-	smpi_exit(errorcode);
-	return 0;
+  smpi_exit(errorcode);
+  return 0;
+}
+
+int SMPI_MPI_Comm_size(MPI_Comm comm, int *size)
+{
+  int retval = MPI_SUCCESS;
+
+  smpi_bench_end();
+
+  if (NULL == comm) {
+    retval = MPI_ERR_COMM;
+  } else if (NULL == size) {
+    retval = MPI_ERR_ARG;
+  } else {
+    *size = comm->size;
+  }
+
+  smpi_bench_begin();
+
+  return retval;
 }
 
-int MPI_Comm_size(MPI_Comm comm, int *size)
+int SMPI_MPI_Comm_rank(MPI_Comm comm, int *rank)
 {
-	int retval = MPI_SUCCESS;
+  int retval = MPI_SUCCESS;
 
-	smpi_bench_end();
+  smpi_bench_end();
 
-	if (NULL == comm) {
-		retval = MPI_ERR_COMM;
-	} else if (NULL == size) {
-		retval = MPI_ERR_ARG;
-	} else {
-		*size = comm->size;
-	}
+  if (NULL == comm) {
+    retval = MPI_ERR_COMM;
+  } else if (NULL == rank) {
+    retval = MPI_ERR_ARG;
+  } else {
+    *rank = smpi_mpi_comm_rank(comm);
+  }
 
-	smpi_bench_begin();
+  smpi_bench_begin();
 
-	return retval;
+  return retval;
 }
 
-int MPI_Comm_rank(MPI_Comm comm, int *rank)
+int SMPI_MPI_Type_size(MPI_Datatype datatype, size_t * size)
 {
-	int retval = MPI_SUCCESS;
+  int retval = MPI_SUCCESS;
 
-	smpi_bench_end();
+  smpi_bench_end();
 
-	if (NULL == comm) {
-		retval = MPI_ERR_COMM;
-	} else if (NULL == rank) {
-		retval = MPI_ERR_ARG;
-	} else {
-		*rank = smpi_mpi_comm_rank(comm);
-	}
+  if (NULL == datatype) {
+    retval = MPI_ERR_TYPE;
+  } else if (NULL == size) {
+    retval = MPI_ERR_ARG;
+  } else {
+    *size = datatype->size;
+  }
 
-	smpi_bench_begin();
+  smpi_bench_begin();
 
-	return retval;
+  return retval;
 }
 
-int MPI_Type_size(MPI_Datatype datatype, size_t *size)
+int SMPI_MPI_Barrier(MPI_Comm comm)
 {
-	int retval = MPI_SUCCESS;
+  int retval = MPI_SUCCESS;
+  int arity=4;
+
+  smpi_bench_end();
 
-	smpi_bench_end();
+  if (NULL == comm) {
+    retval = MPI_ERR_COMM;
+  } else {
 
-	if (NULL == datatype) {
-		retval = MPI_ERR_TYPE;
-	} else if (NULL == size) {
-		retval = MPI_ERR_ARG;
-	} else {
-		*size = datatype->size;
-	}
+    /*
+     * original implemantation:
+     * retval = smpi_mpi_barrier(comm);
+     * this one is unrealistic: it just cond_waits, means no time.
+     */
+     retval = nary_tree_barrier( comm, arity );
+  }
 
-	smpi_bench_begin();
+  smpi_bench_begin();
 
-	return retval;
+  return retval;
 }
 
-int MPI_Barrier(MPI_Comm comm)
+int SMPI_MPI_Irecv(void *buf, int count, MPI_Datatype datatype, int src,
+                   int tag, MPI_Comm comm, MPI_Request * request)
 {
-	int retval = MPI_SUCCESS;
+  int retval = MPI_SUCCESS;
 
-	smpi_bench_end();
+  smpi_bench_end();
 
-	if (NULL == comm) {
-		retval = MPI_ERR_COMM;
-	} else {
-		retval = smpi_mpi_barrier(comm);
-	}
+  retval = smpi_create_request(buf, count, datatype, src, 0, tag, comm,
+                               request);
+  if (NULL != *request && MPI_SUCCESS == retval) {
+    retval = smpi_mpi_irecv(*request);
+  }
 
-	smpi_bench_begin();
+  smpi_bench_begin();
 
-	return retval;
+  return retval;
 }
 
-int MPI_Irecv(void *buf, int count, MPI_Datatype datatype, int src, int tag, MPI_Comm comm, MPI_Request *request)
+int SMPI_MPI_Recv(void *buf, int count, MPI_Datatype datatype, int src,
+                  int tag, MPI_Comm comm, MPI_Status * status)
 {
-	int retval = MPI_SUCCESS;
+  int retval = MPI_SUCCESS;
+  smpi_mpi_request_t request;
 
-	smpi_bench_end();
+  smpi_bench_end();
 
-	retval = smpi_create_request(buf, count, datatype, src, 0, tag, comm, request);
-	if (NULL != *request && MPI_SUCCESS == retval) {
-		retval = smpi_mpi_irecv(*request);
-	}
+  retval = smpi_create_request(buf, count, datatype, src, 0, tag, comm,
+                               &request);
+  if (NULL != request && MPI_SUCCESS == retval) {
+    retval = smpi_mpi_irecv(request);
+    if (MPI_SUCCESS == retval) {
+      retval = smpi_mpi_wait(request, status);
+    }
+    xbt_mallocator_release(smpi_global->request_mallocator, request);
+  }
 
-	smpi_bench_begin();
+  smpi_bench_begin();
 
-	return retval;
+  return retval;
 }
 
-int MPI_Recv(void *buf, int count, MPI_Datatype datatype, int src, int tag, MPI_Comm comm, MPI_Status *status)
+int SMPI_MPI_Isend(void *buf, int count, MPI_Datatype datatype, int dst,
+                   int tag, MPI_Comm comm, MPI_Request * request)
 {
-	int retval = MPI_SUCCESS;
-	smpi_mpi_request_t request;
+  int retval = MPI_SUCCESS;
 
-	smpi_bench_end();
+  smpi_bench_end();
 
-	retval = smpi_create_request(buf, count, datatype, src, 0, tag, comm, &request);
-	if (NULL != request && MPI_SUCCESS == retval) {
-		retval = smpi_mpi_irecv(request);
-		if (MPI_SUCCESS == retval) {
-			retval = smpi_mpi_wait(request, status);
-		}
-		xbt_mallocator_release(smpi_global->request_mallocator, request);
-	}
+  retval = smpi_create_request(buf, count, datatype, 0, dst, tag, comm,
+                               request);
+  if (NULL != *request && MPI_SUCCESS == retval) {
+    retval = smpi_mpi_isend(*request);
+  }
 
-	smpi_bench_begin();
+  smpi_bench_begin();
 
-	return retval;
+  return retval;
 }
 
-int MPI_Isend(void *buf, int count, MPI_Datatype datatype, int dst, int tag, MPI_Comm comm, MPI_Request *request)
+int SMPI_MPI_Send(void *buf, int count, MPI_Datatype datatype, int dst,
+                  int tag, MPI_Comm comm)
 {
-	int retval = MPI_SUCCESS;
+  int retval = MPI_SUCCESS;
+  smpi_mpi_request_t request;
 
-	smpi_bench_end();
+  smpi_bench_end();
 
-	retval = smpi_create_request(buf, count, datatype, 0, dst, tag, comm, request);
-	if (NULL != *request && MPI_SUCCESS == retval) {
-		retval = smpi_mpi_isend(*request);
-	}
+  retval = smpi_create_request(buf, count, datatype, 0, dst, tag, comm,
+                               &request);
+  if (NULL != request && MPI_SUCCESS == retval) {
+    retval = smpi_mpi_isend(request);
+    if (MPI_SUCCESS == retval) {
+      smpi_mpi_wait(request, MPI_STATUS_IGNORE);
+    }
+    xbt_mallocator_release(smpi_global->request_mallocator, request);
+  }
 
-	smpi_bench_begin();
+  smpi_bench_begin();
 
-	return retval;
+  return retval;
+}
+
+/**
+ * MPI_Wait and friends
+ **/
+int SMPI_MPI_Wait(MPI_Request * request, MPI_Status * status)
+{
+  return smpi_mpi_wait(*request, status);
 }
 
-int MPI_Send(void *buf, int count, MPI_Datatype datatype, int dst, int tag, MPI_Comm comm)
+int SMPI_MPI_Waitall(int count, MPI_Request requests[], MPI_Status status[])
 {
-	int retval = MPI_SUCCESS;
-	smpi_mpi_request_t request;
+  return smpi_mpi_waitall(count, requests, status);
+}
 
-	smpi_bench_end();
+int SMPI_MPI_Waitany(int count, MPI_Request requests[], int *index,
+                     MPI_Status status[])
+{
+  return smpi_mpi_waitany(count, requests, index, status);
+}
 
-	retval = smpi_create_request(buf, count, datatype, 0, dst, tag, comm, &request);
-	if (NULL != request && MPI_SUCCESS == retval) {
-		retval = smpi_mpi_isend(request);
-		if (MPI_SUCCESS == retval) {
-			smpi_mpi_wait(request, MPI_STATUS_IGNORE);
-		}
-		xbt_mallocator_release(smpi_global->request_mallocator, request);
-	}
+/**
+ * MPI_Bcast
+ **/
 
-	smpi_bench_begin();
+/**
+ * flat bcast 
+ **/
+int flat_tree_bcast(void *buf, int count, MPI_Datatype datatype, int root, MPI_Comm comm);
+int flat_tree_bcast(void *buf, int count, MPI_Datatype datatype, int root,
+                MPI_Comm comm)
+{
+        int rank;
+        int retval = MPI_SUCCESS;
+        smpi_mpi_request_t request;
+
+        rank = smpi_mpi_comm_rank(comm);
+        if (rank == root) {
+                retval = smpi_create_request(buf, count, datatype, root,
+                                (root + 1) % comm->size, 0, comm, &request);
+                request->forward = comm->size - 1;
+                smpi_mpi_isend(request);
+        } else {
+                retval = smpi_create_request(buf, count, datatype, MPI_ANY_SOURCE, rank,
+                                0, comm, &request);
+                smpi_mpi_irecv(request);
+        }
+
+        smpi_mpi_wait(request, MPI_STATUS_IGNORE);
+        xbt_mallocator_release(smpi_global->request_mallocator, request);
+
+        return(retval);
 
-	return retval;
 }
 
-int MPI_Bcast(void *buf, int count, MPI_Datatype datatype, int root, MPI_Comm comm) {
+/**
+ * Bcast user entry point
+ **/
+int SMPI_MPI_Bcast(void *buf, int count, MPI_Datatype datatype, int root,
+                   MPI_Comm comm)
+{
+  int retval = MPI_SUCCESS;
+
+  smpi_bench_end();
+
+  //retval = flat_tree_bcast(buf, count, datatype, root, comm);
+  retval = nary_tree_bcast(buf, count, datatype, root, comm, 2 );
 
-	int retval = MPI_SUCCESS;
-	int rank;
-	smpi_mpi_request_t request;
+  smpi_bench_begin();
 
-	smpi_bench_end();
+  return retval;
+}
 
-	rank = smpi_mpi_comm_rank(comm);
 
-	if (rank == root) {
-		retval = smpi_create_request(buf, count, datatype, root, (root + 1) % comm->size, 0, comm, &request);
-		request->forward = comm->size - 1;
-		smpi_mpi_isend(request);
-	} else {
-		retval = smpi_create_request(buf, count, datatype, MPI_ANY_SOURCE, rank, 0, comm, &request);
-		smpi_mpi_irecv(request);
-	}
 
-	smpi_mpi_wait(request, MPI_STATUS_IGNORE);
-	xbt_mallocator_release(smpi_global->request_mallocator, request);
+//#ifdef DEBUG_REDUCE
+/**
+ * debugging helper function
+ **/
+static void print_buffer_int(void *buf, int len, char *msg, int rank)
+{
+  int tmp, *v;
+  printf("**[%d] %s: ", rank, msg);
+  for (tmp = 0; tmp < len; tmp++) {
+    v = buf;
+    printf("[%d]", v[tmp]);
+  }
+  printf("\n");
+  free(msg);
+}
+static void print_buffer_double(void *buf, int len, char *msg, int rank)
+{
+  int tmp;
+  double *v;
+  printf("**[%d] %s: ", rank, msg);
+  for (tmp = 0; tmp < len; tmp++) {
+    v = buf;
+    printf("[%lf]", v[tmp]);
+  }
+  printf("\n");
+  free(msg);
+}
 
-	smpi_bench_begin();
 
-	return retval;
+//#endif
+/**
+ * MPI_Reduce
+ **/
+int SMPI_MPI_Reduce(void *sendbuf, void *recvbuf, int count,
+                MPI_Datatype datatype, MPI_Op op, int root, MPI_Comm comm)
+{
+        int retval = MPI_SUCCESS;
+        int rank;
+        int size;
+        int i;
+        int tag = 0;
+        smpi_mpi_request_t *requests;
+        smpi_mpi_request_t request;
+
+        smpi_bench_end();
+
+        rank = smpi_mpi_comm_rank(comm);
+        size = comm->size;
+
+        if (rank != root) {           // if i am not ROOT, simply send my buffer to root
+
+#ifdef DEBUG_REDUCE
+                print_buffer_int(sendbuf, count, xbt_strdup("sndbuf"), rank);
+#endif
+                retval =
+                        smpi_create_request(sendbuf, count, datatype, rank, root, tag, comm,
+                                        &request);
+                smpi_mpi_isend(request);
+                smpi_mpi_wait(request, MPI_STATUS_IGNORE);
+                xbt_mallocator_release(smpi_global->request_mallocator, request);
+
+        } else {
+                // i am the ROOT: wait for all buffers by creating one request by sender
+                int src;
+                requests = xbt_malloc((size-1) * sizeof(smpi_mpi_request_t));
+
+                void **tmpbufs = xbt_malloc((size-1) * sizeof(void *));
+                for (i = 0; i < size-1; i++) {
+                        // we need 1 buffer per request to store intermediate receptions
+                        tmpbufs[i] = xbt_malloc(count * datatype->size);
+                }  
+                // root: initiliaze recv buf with my own snd buf
+                memcpy(recvbuf, sendbuf, count * datatype->size * sizeof(char));  
+
+                // i can not use: 'request->forward = size-1;' (which would progagate size-1 receive reqs)
+                // since we should op values as soon as one receiving request matches.
+                for (i = 0; i < size-1; i++) {
+                        // reminder: for smpi_create_request() the src is always the process sending.
+                        src = i < root ? i : i + 1;
+                        retval = smpi_create_request(tmpbufs[i], count, datatype,
+                                        src, root, tag, comm, &(requests[i]));
+                        if (NULL != requests[i] && MPI_SUCCESS == retval) {
+                                if (MPI_SUCCESS == retval) {
+                                        smpi_mpi_irecv(requests[i]);
+                                }
+                        }
+                }
+                // now, wait for completion of all irecv's.
+                for (i = 0; i < size-1; i++) {
+                        int index = MPI_UNDEFINED;
+                        smpi_mpi_waitany( size-1, requests, &index, MPI_STATUS_IGNORE);
+#ifdef DEBUG_REDUCE
+                        printf ("MPI_Waitany() unblocked: root received (completes req[index=%d])\n",index);
+                        print_buffer_int(tmpbufs[index], count, bprintf("tmpbufs[index=%d] (value received)", index),
+                                        rank);
+#endif
+
+                        // arg 2 is modified
+                        op->func(tmpbufs[index], recvbuf, &count, &datatype);
+#ifdef DEBUG_REDUCE
+                        print_buffer_int(recvbuf, count, xbt_strdup("rcvbuf"), rank);
+#endif
+                        xbt_free(tmpbufs[index]);
+                        /* FIXME: with the following line, it  generates an
+                         * [xbt_ex/CRITICAL] Conditional list not empty 162518800.
+                         */
+                        // xbt_mallocator_release(smpi_global->request_mallocator, requests[index]);
+                }
+                xbt_free(requests);
+                xbt_free(tmpbufs);
+        }
+        smpi_bench_begin();
+        return retval;
 }
 
-// FIXME: needs to return null in event of MPI_UNDEFINED color...
-// FIXME: seriously, this isn't pretty
-int MPI_Comm_split(MPI_Comm comm, int color, int key, MPI_Comm *comm_out)
+/**
+ * MPI_Allreduce
+ *
+ * Same as MPI_REDUCE except that the result appears in the receive buffer of all the group members.
+ **/
+int SMPI_MPI_Allreduce( void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype,
+   		         MPI_Op op, MPI_Comm comm );
+int SMPI_MPI_Allreduce( void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype,
+   		         MPI_Op op, MPI_Comm comm )
 {
-	int retval = MPI_SUCCESS;
-
-	int index, rank;
-	smpi_mpi_request_t request;
-	int colorkey[2];
-	smpi_mpi_status_t status;
-
-	smpi_bench_end();
-
-	// FIXME: need to test parameters
-
-	index = smpi_host_index();
-	rank  = comm->index_to_rank_map[index];
-
-	if (0 == rank) {
-		int *colors = xbt_new(int, comm->size);
-		int *keys   = xbt_new(int, comm->size);
-		int i, j, k;
-		smpi_mpi_communicator_t tempcomm = NULL;
-		int colortmp;
-		int keycount;
-		int *keystmp  = xbt_new(int, comm->size);
-		int *rankstmp = xbt_new(int, comm->size);
-		int tmpval;
-		int indextmp;
-
-		colors[0] = color;
-		keys[0]   = key;
-
-		// FIXME: not efficient
-		for (i = 1; i < comm->size; i++) {
-			retval = smpi_create_request(colorkey, 2, MPI_INT, MPI_ANY_SOURCE, rank, MPI_ANY_TAG, comm, &request);
-			smpi_mpi_irecv(request);
-			smpi_mpi_wait(request, &status);
-			xbt_mallocator_release(smpi_global->request_mallocator, request);
-			colors[i] = colorkey[0];
-			keys[i]   = colorkey[1];
-		}
-
-		for (i = 0; i < comm->size; i++) {
-			if (-1 == colors[i]) {
-				continue;
-			}
-			colortmp = colors[i];
-			keycount = 0;
-			for (j = i; j < comm->size; j++) {
-				if(colortmp == colors[j]) {
-					colors[j] = -1;
-					keystmp[keycount] = keys[j];
-					rankstmp[keycount] = j;
-					keycount++;
-				}
+  int retval = MPI_SUCCESS;
+  int root=1;  // arbitrary choice
+
+  smpi_bench_end();
+
+  retval = SMPI_MPI_Reduce( sendbuf, recvbuf, count, datatype, op, root, comm);
+  if (MPI_SUCCESS != retval)
+	    return(retval);
+
+  retval = SMPI_MPI_Bcast( sendbuf, count, datatype, root, comm);
+  smpi_bench_begin();
+  return( retval );
+}
+
+
+/**
+ * MPI_Scatter user entry point
+ **/
+//int SMPI_MPI_Scatter(void *sendbuf, int sendcount, MPI_Datatype datatype, 
+//		         void *recvbuf, int recvcount, MPI_Datatype recvtype,int root,
+//		        MPI_Comm comm);
+int SMPI_MPI_Scatter(void *sendbuf, int sendcount, MPI_Datatype datatype, 
+		         void *recvbuf, int recvcount, MPI_Datatype recvtype,
+			   int root, MPI_Comm comm)
+{
+  int retval = MPI_SUCCESS;
+  int i;
+  int cnt=0;  
+  int rank;
+  int tag=0;
+  char *cptr;  // to manipulate the void * buffers
+  smpi_mpi_request_t *requests;
+  smpi_mpi_request_t request;
+  smpi_mpi_status_t status;
+
+
+  smpi_bench_end();
+
+  rank = smpi_mpi_comm_rank(comm);
+
+  requests = xbt_malloc((comm->size-1) * sizeof(smpi_mpi_request_t));
+  if (rank == root) {
+          // i am the root: distribute my sendbuf
+          //print_buffer_int(sendbuf, comm->size, xbt_strdup("rcvbuf"), rank);
+          cptr = sendbuf;
+          for (i=0; i < comm->size; i++) {
+                  if ( i!=root ) { // send to processes ...
+
+                          retval = smpi_create_request((void *)cptr, sendcount, 
+                                          datatype, root, i, tag, comm, &(requests[cnt]));
+                          if (NULL != requests[cnt] && MPI_SUCCESS == retval) {
+                                  if (MPI_SUCCESS == retval) {
+                                          smpi_mpi_isend(requests[cnt]);
+                                  }
+				  }
+				  cnt++;
+			} 
+			else { // ... except if it's me.
+				  memcpy(recvbuf, (void *)cptr, recvcount*recvtype->size*sizeof(char));
 			}
-			if (0 < keycount) {
-				// FIXME: yes, mock me, bubble sort...
-				for (j = 0; j < keycount; j++) {
-					for (k = keycount - 1; k > j; k--) {
-						if (keystmp[k] < keystmp[k - 1]) {
-							tmpval          = keystmp[k];
-							keystmp[k]      = keystmp[k - 1];
-							keystmp[k - 1]  = tmpval;
-
-							tmpval          = rankstmp[k];
-							rankstmp[k]     = rankstmp[k - 1];
-							rankstmp[k - 1] = tmpval;
-						}
-					}
-				}
-				tempcomm                    = xbt_new(s_smpi_mpi_communicator_t, 1);
-				tempcomm->barrier_count     = 0;
-				tempcomm->barrier_mutex     = SIMIX_mutex_init();
-				tempcomm->barrier_cond      = SIMIX_cond_init();
-				tempcomm->rank_to_index_map = xbt_new(int, keycount);
-				tempcomm->index_to_rank_map = xbt_new(int, smpi_global->host_count);
-				for (j = 0; j < smpi_global->host_count; j++) {
-					tempcomm->index_to_rank_map[j] = -1;
-				}
-				for (j = 0; j < keycount; j++) {
-					indextmp = comm->rank_to_index_map[rankstmp[j]];
-					tempcomm->rank_to_index_map[j]        = indextmp;
-					tempcomm->index_to_rank_map[indextmp] = j;
-				}
-				for (j = 0; j < keycount; j++) {
-					retval = smpi_create_request(&j, 1, MPI_INT, 0, rankstmp[j], 0, comm, &request);
-					request->data = tempcomm;
-					smpi_mpi_isend(request);
-					smpi_mpi_wait(request, &status);
-					xbt_mallocator_release(smpi_global->request_mallocator, request);
-				}
+                  cptr += sendcount*datatype->size;
+	    }
+	    for(i=0; i<cnt; i++) { // wait for send to complete
+			    /* FIXME: waitall() should be slightly better */
+			    smpi_mpi_wait(requests[i], &status);
+			    xbt_mallocator_release(smpi_global->request_mallocator, requests[i]);
+
+	    }
+  } 
+  else {  // i am a non-root process: wait data from the root
+	    retval = smpi_create_request(recvbuf,recvcount, 
+				  recvtype, root, rank, tag, comm, &request);
+	    if (NULL != request && MPI_SUCCESS == retval) {
+			if (MPI_SUCCESS == retval) {
+				  smpi_mpi_irecv(request);
 			}
-		}
-	} else {
-		colorkey[0] = color;
-		colorkey[1] = key;
-		retval = smpi_create_request(colorkey, 2, MPI_INT, rank, 0, 0, comm, &request);
-		smpi_mpi_isend(request);
-		smpi_mpi_wait(request, &status);
-		xbt_mallocator_release(smpi_global->request_mallocator, request);
-		retval = smpi_create_request(colorkey, 1, MPI_INT, 0, rank, 0, comm, &request);
-		smpi_mpi_irecv(request);
-		smpi_mpi_wait(request, &status);
-		*comm_out = request->data;
-	}
-
-	smpi_bench_begin();
-
-	return retval;
+	    }
+	    smpi_mpi_wait(request, &status);
+	    xbt_mallocator_release(smpi_global->request_mallocator, request);
+  }
+  xbt_free(requests);
+
+  smpi_bench_begin();
+
+  return retval;
+}
+
+
+
+
+
+
+// used by comm_split to sort ranks based on key values
+int smpi_compare_rankkeys(const void *a, const void *b);
+int smpi_compare_rankkeys(const void *a, const void *b)
+{
+  int *x = (int *) a;
+  int *y = (int *) b;
+
+  if (x[1] < y[1])
+    return -1;
+
+  if (x[1] == y[1]) {
+    if (x[0] < y[0])
+      return -1;
+    if (x[0] == y[0])
+      return 0;
+    return 1;
+  }
+
+  return 1;
+}
+
+int SMPI_MPI_Comm_split(MPI_Comm comm, int color, int key,
+                        MPI_Comm * comm_out)
+{
+  int retval = MPI_SUCCESS;
+
+  int index, rank;
+  smpi_mpi_request_t request;
+  int colorkey[2];
+  smpi_mpi_status_t status;
+
+  smpi_bench_end();
+
+  // FIXME: need to test parameters
+
+  index = smpi_process_index();
+  rank = comm->index_to_rank_map[index];
+
+  // default output
+  comm_out = NULL;
+
+  // root node does most of the real work
+  if (0 == rank) {
+    int colormap[comm->size];
+    int keymap[comm->size];
+    int rankkeymap[comm->size * 2];
+    int i, j;
+    smpi_mpi_communicator_t tempcomm = NULL;
+    int count;
+    int indextmp;
+
+    colormap[0] = color;
+    keymap[0] = key;
+
+    // FIXME: use scatter/gather or similar instead of individual comms
+    for (i = 1; i < comm->size; i++) {
+      retval = smpi_create_request(colorkey, 2, MPI_INT, MPI_ANY_SOURCE,
+                                   rank, MPI_ANY_TAG, comm, &request);
+      smpi_mpi_irecv(request);
+      smpi_mpi_wait(request, &status);
+      colormap[status.MPI_SOURCE] = colorkey[0];
+      keymap[status.MPI_SOURCE] = colorkey[1];
+      xbt_mallocator_release(smpi_global->request_mallocator, request);
+    }
+
+    for (i = 0; i < comm->size; i++) {
+      if (MPI_UNDEFINED == colormap[i]) {
+        continue;
+      }
+      // make a list of nodes with current color and sort by keys
+      count = 0;
+      for (j = i; j < comm->size; j++) {
+        if (colormap[i] == colormap[j]) {
+          colormap[j] = MPI_UNDEFINED;
+          rankkeymap[count * 2] = j;
+          rankkeymap[count * 2 + 1] = keymap[j];
+          count++;
+        }
+      }
+      qsort(rankkeymap, count, sizeof(int) * 2, &smpi_compare_rankkeys);
+
+      // new communicator
+      tempcomm = xbt_new(s_smpi_mpi_communicator_t, 1);
+      tempcomm->barrier_count = 0;
+      tempcomm->size = count;
+      tempcomm->barrier_mutex = SIMIX_mutex_init();
+      tempcomm->barrier_cond = SIMIX_cond_init();
+      tempcomm->rank_to_index_map = xbt_new(int, count);
+      tempcomm->index_to_rank_map = xbt_new(int, smpi_global->process_count);
+      for (j = 0; j < smpi_global->process_count; j++) {
+        tempcomm->index_to_rank_map[j] = -1;
+      }
+      for (j = 0; j < count; j++) {
+        indextmp = comm->rank_to_index_map[rankkeymap[j * 2]];
+        tempcomm->rank_to_index_map[j] = indextmp;
+        tempcomm->index_to_rank_map[indextmp] = j;
+      }
+      for (j = 0; j < count; j++) {
+        if (rankkeymap[j * 2]) {
+          retval = smpi_create_request(&j, 1, MPI_INT, 0,
+                                       rankkeymap[j * 2], 0, comm, &request);
+          request->data = tempcomm;
+          smpi_mpi_isend(request);
+          smpi_mpi_wait(request, &status);
+          xbt_mallocator_release(smpi_global->request_mallocator, request);
+        } else {
+          *comm_out = tempcomm;
+        }
+      }
+    }
+  } else {
+    colorkey[0] = color;
+    colorkey[1] = key;
+    retval = smpi_create_request(colorkey, 2, MPI_INT, rank, 0, 0, comm,
+                                 &request);
+    smpi_mpi_isend(request);
+    smpi_mpi_wait(request, &status);
+    xbt_mallocator_release(smpi_global->request_mallocator, request);
+    if (MPI_UNDEFINED != color) {
+      retval = smpi_create_request(colorkey, 1, MPI_INT, 0, rank, 0, comm,
+                                   &request);
+      smpi_mpi_irecv(request);
+      smpi_mpi_wait(request, &status);
+      *comm_out = request->data;
+    }
+  }
+
+  smpi_bench_begin();
+
+  return retval;
 }
+
+double SMPI_MPI_Wtime(void)
+{
+  return (SIMIX_get_clock());
+}
+
+