X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/f776050cb7325db407124e7d4eac63a25a048528..0afab0e550e09d35a4aaaae802c7f2ea17d2b860:/src/smpi/smpi_base.c

diff --git a/src/smpi/smpi_base.c b/src/smpi/smpi_base.c
index f221d21b7b..1387109e0e 100644
--- a/src/smpi/smpi_base.c
+++ b/src/smpi/smpi_base.c
@@ -2,38 +2,34 @@
  * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
-  * under the terms of the license (GNU LGPL) which comes with this package. */
+ * under the terms of the license (GNU LGPL) which comes with this package. */
 
 #include "private.h"
 #include "xbt/time.h"
 #include "mc/mc.h"
+#include "xbt/replay.h"
+#include <errno.h>
+#include "surf/surf.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);
-
-static int match_recv(void* a, void* b) {
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smpi_base, smpi, "Logging specific to SMPI (base)");
+
+
+static int match_recv(void* a, void* b, smx_action_t ignored) {
    MPI_Request ref = (MPI_Request)a;
    MPI_Request req = (MPI_Request)b;
+   XBT_DEBUG("Trying to match a recv of src %d against %d, tag %d against %d",ref->src,req->src, ref->tag, req->tag);
 
-   xbt_assert(ref, "Cannot match recv against null reference");
-   xbt_assert(req, "Cannot match recv against null request");
-   return (ref->src == MPI_ANY_SOURCE || req->src == ref->src)
-          && (ref->tag == MPI_ANY_TAG || req->tag == ref->tag);
+  xbt_assert(ref, "Cannot match recv against null reference");
+  xbt_assert(req, "Cannot match recv against null request");
+  return (ref->src == MPI_ANY_SOURCE || req->src == ref->src)
+    && (ref->tag == MPI_ANY_TAG || req->tag == ref->tag);
 }
 
-static int match_send(void* a, void* b) {
+static int match_send(void* a, void* b,smx_action_t ignored) {
    MPI_Request ref = (MPI_Request)a;
    MPI_Request req = (MPI_Request)b;
-
+   XBT_DEBUG("Trying to match a send of src %d against %d, tag %d against %d",ref->src,req->src, ref->tag, req->tag);
    xbt_assert(ref, "Cannot match send against null reference");
    xbt_assert(req, "Cannot match send against null request");
    return (req->src == MPI_ANY_SOURCE || req->src == ref->src)
@@ -46,8 +42,27 @@ static MPI_Request build_request(void *buf, int count,
 {
   MPI_Request request;
 
+  void *old_buf;
+
   request = xbt_new(s_smpi_mpi_request_t, 1);
+
+  s_smpi_subtype_t *subtype = datatype->substruct;
+
+  if(datatype->has_subtype == 1){
+    // This part handles the problem of non-contignous memory
+    old_buf = buf;
+    buf = malloc(count*smpi_datatype_size(datatype));
+    if (flags & SEND) {
+      subtype->serialize(old_buf, buf, count, datatype->substruct);
+    }
+  }
+
   request->buf = buf;
+  // This part handles the problem of non-contignous memory (for the
+  // unserialisation at the reception)
+  request->old_buf = old_buf;
+  request->old_type = datatype;
+
   request->size = smpi_datatype_size(datatype) * count;
   request->src = src;
   request->dst = dst;
@@ -62,13 +77,57 @@ static MPI_Request build_request(void *buf, int count,
   return request;
 }
 
+
+void smpi_empty_status(MPI_Status * status) {
+  if(status != MPI_STATUS_IGNORE) {
+      status->MPI_SOURCE=MPI_ANY_SOURCE;
+      status->MPI_TAG=MPI_ANY_TAG;
+      status->count=0;
+  }
+}
+
+void smpi_action_trace_run(char *path)
+{
+  char *name;
+  xbt_dynar_t todo;
+  xbt_dict_cursor_t cursor;
+
+  action_fp=NULL;
+  if (path) {
+    action_fp = fopen(path, "r");
+    xbt_assert(action_fp != NULL, "Cannot open %s: %s", path,
+               strerror(errno));
+  }
+
+  if (!xbt_dict_is_empty(action_queues)) {
+    XBT_WARN
+      ("Not all actions got consumed. If the simulation ended successfully (without deadlock), you may want to add new processes to your deployment file.");
+
+
+    xbt_dict_foreach(action_queues, cursor, name, todo) {
+      XBT_WARN("Still %lu actions for %s", xbt_dynar_length(todo), name);
+    }
+  }
+
+  if (path)
+    fclose(action_fp);
+  xbt_dict_free(&action_queues);
+  action_queues = xbt_dict_new_homogeneous(NULL);
+}
+
+static void smpi_mpi_request_free_voidp(void* request)
+{
+  MPI_Request req = request;
+  smpi_mpi_request_free(&req);
+}
+
 /* MPI Low level calls */
 MPI_Request smpi_mpi_send_init(void *buf, int count, MPI_Datatype datatype,
                                int dst, int tag, MPI_Comm comm)
 {
   MPI_Request request =
-      build_request(buf, count, datatype, smpi_comm_rank(comm), dst, tag,
-                    comm, PERSISTENT | SEND);
+    build_request(buf, count, datatype, smpi_comm_rank(comm), dst, tag,
+                  comm, PERSISTENT | SEND);
 
   return request;
 }
@@ -77,8 +136,8 @@ MPI_Request smpi_mpi_recv_init(void *buf, int count, MPI_Datatype datatype,
                                int src, int tag, MPI_Comm comm)
 {
   MPI_Request request =
-      build_request(buf, count, datatype, src, smpi_comm_rank(comm), tag,
-                    comm, PERSISTENT | RECV);
+    build_request(buf, count, datatype, src, smpi_comm_rank(comm), tag,
+                  comm, PERSISTENT | RECV);
 
   return request;
 }
@@ -86,22 +145,55 @@ MPI_Request smpi_mpi_recv_init(void *buf, int count, MPI_Datatype datatype,
 void smpi_mpi_start(MPI_Request request)
 {
   smx_rdv_t mailbox;
+  int detached = 0;
 
   xbt_assert(!request->action,
-              "Cannot (re)start a non-finished communication");
+             "Cannot (re)start a non-finished communication");
   if(request->flags & RECV) {
     print_request("New recv", request);
-    mailbox = smpi_process_mailbox();
-    request->action = SIMIX_req_comm_irecv(mailbox, request->buf, &request->size, &match_recv, request);
+    if (request->size < xbt_cfg_get_int(_surf_cfg_set, "smpi/async_small_thres"))
+      mailbox = smpi_process_mailbox_small();
+    else
+      mailbox = smpi_process_mailbox();
+
+    // FIXME: SIMIX does not yet support non-contiguous datatypes
+    request->action = simcall_comm_irecv(mailbox, request->buf, &request->size, &match_recv, request);
   } else {
     print_request("New send", request);
-    mailbox = smpi_process_remote_mailbox(request->dst);
-    request->action = SIMIX_req_comm_isend(mailbox, request->size, -1.0,
-                                           request->buf, request->size, &match_send, request, 0);
+    if (request->size < xbt_cfg_get_int(_surf_cfg_set, "smpi/async_small_thres")) { // eager mode
+      mailbox = smpi_process_remote_mailbox_small(
+                                                  smpi_group_index(smpi_comm_group(request->comm), request->dst));
+    }else{
+      XBT_DEBUG("Send request %p is not in the permanent receive mailbox (buf: %p)",request,request->buf);
+      mailbox = smpi_process_remote_mailbox(
+                                            smpi_group_index(smpi_comm_group(request->comm), request->dst));
+    }
+    if (request->size < 64*1024 ) { //(FIXME: this limit should be configurable)
+      void *oldbuf = request->buf;
+      detached = 1;
+      request->buf = malloc(request->size);
+      if (oldbuf)
+        memcpy(request->buf,oldbuf,request->size);
+      XBT_DEBUG("Send request %p is detached; buf %p copied into %p",request,oldbuf,request->buf);
+    }
+
+    request->action =
+      simcall_comm_isend(mailbox, request->size, -1.0,
+                         request->buf, request->size,
+                         &match_send,
+                         &smpi_mpi_request_free_voidp, // how to free the userdata if a detached send fails
+                         request,
+                         // detach if msg size < eager/rdv switch limit
+                         detached);
+
 #ifdef HAVE_TRACING
-    SIMIX_req_set_category (request->action, TRACE_internal_smpi_get_category());
+    /* FIXME: detached sends are not traceable (request->action == NULL) */
+    if (request->action)
+      simcall_set_category(request->action, TRACE_internal_smpi_get_category());
 #endif
+
   }
+
 }
 
 void smpi_mpi_startall(int count, MPI_Request * requests)
@@ -123,8 +215,8 @@ MPI_Request smpi_isend_init(void *buf, int count, MPI_Datatype datatype,
                             int dst, int tag, MPI_Comm comm)
 {
   MPI_Request request =
-      build_request(buf, count, datatype, smpi_comm_rank(comm), dst, tag,
-                    comm, NON_PERSISTENT | SEND);
+    build_request(buf, count, datatype, smpi_comm_rank(comm), dst, tag,
+                  comm, NON_PERSISTENT | SEND);
 
   return request;
 }
@@ -133,7 +225,7 @@ MPI_Request smpi_mpi_isend(void *buf, int count, MPI_Datatype datatype,
                            int dst, int tag, MPI_Comm comm)
 {
   MPI_Request request =
-      smpi_isend_init(buf, count, datatype, dst, tag, comm);
+    smpi_isend_init(buf, count, datatype, dst, tag, comm);
 
   smpi_mpi_start(request);
   return request;
@@ -143,9 +235,8 @@ MPI_Request smpi_irecv_init(void *buf, int count, MPI_Datatype datatype,
                             int src, int tag, MPI_Comm comm)
 {
   MPI_Request request =
-      build_request(buf, count, datatype, src, smpi_comm_rank(comm), tag,
-                    comm, NON_PERSISTENT | RECV);
-
+    build_request(buf, count, datatype, src, smpi_comm_rank(comm), tag,
+                  comm, NON_PERSISTENT | RECV);
   return request;
 }
 
@@ -153,7 +244,7 @@ MPI_Request smpi_mpi_irecv(void *buf, int count, MPI_Datatype datatype,
                            int src, int tag, MPI_Comm comm)
 {
   MPI_Request request =
-      smpi_irecv_init(buf, count, datatype, src, tag, comm);
+    smpi_irecv_init(buf, count, datatype, src, tag, comm);
 
   smpi_mpi_start(request);
   return request;
@@ -163,11 +254,12 @@ void smpi_mpi_recv(void *buf, int count, MPI_Datatype datatype, int src,
                    int tag, MPI_Comm comm, MPI_Status * status)
 {
   MPI_Request request;
-
   request = smpi_mpi_irecv(buf, count, datatype, src, tag, comm);
   smpi_mpi_wait(&request, status);
 }
 
+
+
 void smpi_mpi_send(void *buf, int count, MPI_Datatype datatype, int dst,
                    int tag, MPI_Comm comm)
 {
@@ -186,9 +278,9 @@ void smpi_mpi_sendrecv(void *sendbuf, int sendcount, MPI_Datatype sendtype,
   MPI_Status stats[2];
 
   requests[0] =
-      smpi_isend_init(sendbuf, sendcount, sendtype, dst, sendtag, comm);
+    smpi_isend_init(sendbuf, sendcount, sendtype, dst, sendtag, comm);
   requests[1] =
-      smpi_irecv_init(recvbuf, recvcount, recvtype, src, recvtag, comm);
+    smpi_irecv_init(recvbuf, recvcount, recvtype, src, recvtag, comm);
   smpi_mpi_startall(2, requests);
   smpi_mpi_waitall(2, requests, stats);
   if(status != MPI_STATUS_IGNORE) {
@@ -205,14 +297,35 @@ int smpi_mpi_get_count(MPI_Status * status, MPI_Datatype datatype)
 static void finish_wait(MPI_Request * request, MPI_Status * status)
 {
   MPI_Request req = *request;
+  // if we have a sender, we should use its data, and not the data from the receive
+  if((req->action)&&
+     (req->src==MPI_ANY_SOURCE || req->tag== MPI_ANY_TAG))
+    req = (MPI_Request)SIMIX_comm_get_src_data((*request)->action);
 
   if(status != MPI_STATUS_IGNORE) {
     status->MPI_SOURCE = req->src;
     status->MPI_TAG = req->tag;
     status->MPI_ERROR = MPI_SUCCESS;
+    // FIXME: really this should just contain the count of receive-type blocks,
+    // right?
     status->count = req->size;
   }
+  req = *request;
+
   print_request("Finishing", req);
+  MPI_Datatype datatype = req->old_type;
+  if(datatype->has_subtype == 1){
+      // This part handles the problem of non-contignous memory
+      // the unserialization at the reception
+    s_smpi_subtype_t *subtype = datatype->substruct;
+    if(req->flags & RECV) {
+      subtype->unserialize(req->buf, req->old_buf, req->size/smpi_datatype_size(datatype) , datatype->substruct);
+    }
+    //FIXME: I am not sure that if the send is detached we have to free
+    //the sender buffer thus I do it only for the reciever
+    if(req->flags & RECV) free(req->buf);
+  }
+
   if(req->flags & NON_PERSISTENT) {
     smpi_mpi_request_free(request);
   } else {
@@ -220,14 +333,20 @@ static void finish_wait(MPI_Request * request, MPI_Status * status)
   }
 }
 
-int smpi_mpi_test(MPI_Request * request, MPI_Status * status)
-{
-   int flag = SIMIX_req_comm_test((*request)->action);
+int smpi_mpi_test(MPI_Request * request, MPI_Status * status) {
+  int flag;
 
-   if(flag) {
-      smpi_mpi_wait(request, status);
-   }
-   return flag;
+  //assume that request is not MPI_REQUEST_NULL (filtered in PMPI_Test or smpi_mpi_testall before)
+  if ((*request)->action == NULL)
+    flag = 1;
+  else
+    flag = simcall_comm_test((*request)->action);
+  if(flag) {
+    finish_wait(request, status);
+  }else{
+    smpi_empty_status(status);
+  }
+  return flag;
 }
 
 int smpi_mpi_testany(int count, MPI_Request requests[], int *index,
@@ -244,31 +363,112 @@ int smpi_mpi_testany(int count, MPI_Request requests[], int *index,
     map = xbt_new(int, count);
     size = 0;
     for(i = 0; i < count; i++) {
-      if(requests[i]->action) {
+      if((requests[i]!=MPI_REQUEST_NULL) && requests[i]->action) {
          xbt_dynar_push(comms, &requests[i]->action);
          map[size] = i;
          size++;
       }
     }
     if(size > 0) {
-      *index = SIMIX_req_comm_testany(comms);
-      *index = map[*index];
-      if(*index != MPI_UNDEFINED) {
-        smpi_mpi_wait(&requests[*index], status);
+      i = simcall_comm_testany(comms);
+      // not MPI_UNDEFINED, as this is a simix return code
+      if(i != -1) {
+        *index = map[i];
+        finish_wait(&requests[*index], status);
         flag = 1;
       }
+    }else{
+        //all requests are null or inactive, return true
+        flag=1;
+        smpi_empty_status(status);
     }
     xbt_free(map);
     xbt_dynar_free(&comms);
   }
+
+  return flag;
+}
+
+
+int smpi_mpi_testall(int count, MPI_Request requests[],
+                     MPI_Status status[])
+{
+  MPI_Status stat;
+  MPI_Status *pstat = status == MPI_STATUSES_IGNORE ? MPI_STATUS_IGNORE : &stat;
+  int flag=1;
+  int i;
+  for(i=0; i<count; i++){
+    if(requests[i]!= MPI_REQUEST_NULL){
+      if (smpi_mpi_test(&requests[i], pstat)!=1){
+        flag=0;
+      }
+    }else{
+      smpi_empty_status(pstat);
+    }
+    if(status != MPI_STATUSES_IGNORE) {
+      memcpy(&status[i], pstat, sizeof(*pstat));
+    }
+  }
   return flag;
 }
 
+void smpi_mpi_probe(int source, int tag, MPI_Comm comm, MPI_Status* status){
+  int flag=0;
+  //FIXME find another wait to avoid busy waiting ?
+  // the issue here is that we have to wait on a nonexistent comm
+  while(flag==0){
+    smpi_mpi_iprobe(source, tag, comm, &flag, status);
+    XBT_DEBUG("Busy Waiting on probing : %d", flag);
+    if(!flag) {
+      simcall_process_sleep(0.0001);
+    }
+  }
+}
+
+void smpi_mpi_iprobe(int source, int tag, MPI_Comm comm, int* flag, MPI_Status* status){
+  MPI_Request request =build_request(NULL, 0, MPI_CHAR, source, smpi_comm_rank(comm), tag,
+            comm, NON_PERSISTENT | RECV);
+
+  // behave like a receive, but don't do it
+  smx_rdv_t mailbox;
+
+  print_request("New iprobe", request);
+  // We have to test both mailboxes as we don't know if we will receive one one or another
+    if (xbt_cfg_get_int(_surf_cfg_set, "smpi/async_small_thres")>0){
+        mailbox = smpi_process_mailbox_small();
+        XBT_DEBUG("trying to probe the perm recv mailbox");
+        request->action = simcall_comm_iprobe(mailbox, request->src, request->tag, &match_recv, (void*)request);
+    }
+    if (request->action==NULL){
+	mailbox = smpi_process_mailbox();
+        XBT_DEBUG("trying to probe the other mailbox");
+        request->action = simcall_comm_iprobe(mailbox, request->src, request->tag, &match_recv, (void*)request);
+    }
+
+  if(request->action){
+    MPI_Request req = (MPI_Request)SIMIX_comm_get_src_data(request->action);
+    *flag=true;
+    if(status != MPI_STATUS_IGNORE) {
+      status->MPI_SOURCE = req->src;
+      status->MPI_TAG = req->tag;
+      status->MPI_ERROR = MPI_SUCCESS;
+      status->count = req->size;
+    }
+  }
+  else *flag=false;
+  smpi_mpi_request_free(&request);
+
+  return;
+}
+
 void smpi_mpi_wait(MPI_Request * request, MPI_Status * status)
 {
   print_request("Waiting", *request);
-  SIMIX_req_comm_wait((*request)->action, -1.0);
-  finish_wait(request, status);
+  if ((*request)->action != NULL) { // this is not a detached send
+    simcall_comm_wait((*request)->action, -1.0);
+    finish_wait(request, status);
+  }
+  // FIXME for a detached send, finish_wait is not called:
 }
 
 int smpi_mpi_waitany(int count, MPI_Request requests[],
@@ -286,43 +486,64 @@ int smpi_mpi_waitany(int count, MPI_Request requests[],
     size = 0;
     XBT_DEBUG("Wait for one of");
     for(i = 0; i < count; i++) {
-      if(requests[i] != MPI_REQUEST_NULL) {
-        print_request("   ", requests[i]);
+      if((requests[i] != MPI_REQUEST_NULL) && (requests[i]->action != NULL)) {
+        print_request("Waiting any ", requests[i]);
         xbt_dynar_push(comms, &requests[i]->action);
         map[size] = i;
         size++;
       }
     }
     if(size > 0) {
-      index = SIMIX_req_comm_waitany(comms);
-      index = map[index];
-      finish_wait(&requests[index], status);
+      i = simcall_comm_waitany(comms);
+
+      // not MPI_UNDEFINED, as this is a simix return code
+      if (i != -1) {
+        index = map[i];
+        finish_wait(&requests[index], status);
+      }
     }
     xbt_free(map);
     xbt_dynar_free(&comms);
   }
+
+  if (index==MPI_UNDEFINED)
+    smpi_empty_status(status);
+
   return index;
 }
 
 void smpi_mpi_waitall(int count, MPI_Request requests[],
                       MPI_Status status[])
 {
-  int index, c;
+  int  index, c;
   MPI_Status stat;
-  MPI_Status *pstat = status == MPI_STATUS_IGNORE ? MPI_STATUS_IGNORE : &stat;
-
+  MPI_Status *pstat = status == MPI_STATUSES_IGNORE ? MPI_STATUS_IGNORE : &stat;
+  //tag invalid requests in the set
   for(c = 0; c < count; c++) {
-    if(MC_IS_ENABLED) {
-      smpi_mpi_wait(&requests[c], pstat);
-      index = c;
-    } else {
-      index = smpi_mpi_waitany(count, requests, pstat);
-      if(index == MPI_UNDEFINED) {
-        break;
+    if(requests[c]==MPI_REQUEST_NULL || requests[c]->dst == MPI_PROC_NULL ){
+      if(status != MPI_STATUSES_IGNORE)
+        smpi_empty_status(&status[c]);
+    }else if(requests[c]->src == MPI_PROC_NULL ){
+      if(status != MPI_STATUSES_IGNORE) {
+        smpi_empty_status(&status[c]);
+        status[c].MPI_SOURCE=MPI_PROC_NULL;
       }
     }
-    if(status != MPI_STATUS_IGNORE) {
-      memcpy(&status[index], pstat, sizeof(*pstat));
+  }
+
+  for(c = 0; c < count; c++) {
+      if(MC_IS_ENABLED) {
+        smpi_mpi_wait(&requests[c], pstat);
+        index = c;
+      } else {
+        index = smpi_mpi_waitany(count, requests, pstat);
+        if(index == MPI_UNDEFINED) {
+          break;
+       }
+      if(status != MPI_STATUSES_IGNORE) {
+        memcpy(&status[index], pstat, sizeof(*pstat));
+
+      }
     }
   }
 }
@@ -331,17 +552,51 @@ int smpi_mpi_waitsome(int incount, MPI_Request requests[], int *indices,
                       MPI_Status status[])
 {
   int i, count, index;
+  MPI_Status stat;
+  MPI_Status *pstat = status == MPI_STATUSES_IGNORE ? MPI_STATUS_IGNORE : &stat;
 
   count = 0;
-  for(i = 0; i < incount; i++) {
-     if(smpi_mpi_testany(incount, requests, &index, status)) {
-       indices[count] = index;
-       count++;
-     }
+  for(i = 0; i < incount; i++)
+  {
+    index=smpi_mpi_waitany(incount, requests, pstat);
+    if(index!=MPI_UNDEFINED){
+      indices[count] = index;
+      count++;
+      if(status != MPI_STATUSES_IGNORE) {
+        memcpy(&status[index], pstat, sizeof(*pstat));
+      }
+    }else{
+      return MPI_UNDEFINED;
+    }
   }
   return count;
 }
 
+int smpi_mpi_testsome(int incount, MPI_Request requests[], int *indices,
+                      MPI_Status status[])
+{
+  int i, count, count_dead;
+  MPI_Status stat;
+  MPI_Status *pstat = status == MPI_STATUSES_IGNORE ? MPI_STATUS_IGNORE : &stat;
+
+  count = 0;
+  for(i = 0; i < incount; i++) {
+    if((requests[i] != MPI_REQUEST_NULL)) {
+      if(smpi_mpi_test(&requests[i], pstat)) {
+         indices[count] = i;
+         count++;
+         if(status != MPI_STATUSES_IGNORE) {
+            memcpy(&status[i], pstat, sizeof(*pstat));
+         }
+      }
+    }else{
+      count_dead++;
+    }
+  }
+  if(count_dead==incount)return MPI_UNDEFINED;
+  else return count;
+}
+
 void smpi_mpi_bcast(void *buf, int count, MPI_Datatype datatype, int root,
                     MPI_Comm comm)
 {
@@ -360,7 +615,8 @@ void smpi_mpi_gather(void *sendbuf, int sendcount, MPI_Datatype sendtype,
                      int root, MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, src, index, sendsize, recvsize;
+  int rank, size, src, index;
+  MPI_Aint lb = 0, recvext = 0;
   MPI_Request *requests;
 
   rank = smpi_comm_rank(comm);
@@ -369,20 +625,19 @@ void smpi_mpi_gather(void *sendbuf, int sendcount, MPI_Datatype sendtype,
     // 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);
+    // FIXME: check for errors
+    smpi_datatype_extent(recvtype, &lb, &recvext);
     // Local copy from root
-    memcpy(&((char *) recvbuf)[root * recvcount * recvsize], sendbuf,
-           sendcount * sendsize * sizeof(char));
+    smpi_datatype_copy(sendbuf, sendcount, sendtype,
+                       (char *)recvbuf + root * recvcount * recvext, recvcount, recvtype);
     // 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_irecv_init(&((char *) recvbuf)
-                                          [src * recvcount * recvsize],
-                                          recvcount, recvtype, src,
-                                          system_tag, comm);
+        requests[index] = smpi_irecv_init((char *)recvbuf + src * recvcount * recvext,
+                                          recvcount, recvtype,
+                                          src, system_tag, comm);
         index++;
       }
     }
@@ -398,7 +653,8 @@ void smpi_mpi_gatherv(void *sendbuf, int sendcount, MPI_Datatype sendtype,
                       MPI_Datatype recvtype, int root, MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, src, index, sendsize;
+  int rank, size, src, index;
+  MPI_Aint lb = 0, recvext = 0;
   MPI_Request *requests;
 
   rank = smpi_comm_rank(comm);
@@ -407,19 +663,20 @@ void smpi_mpi_gatherv(void *sendbuf, int sendcount, MPI_Datatype sendtype,
     // Send buffer to root
     smpi_mpi_send(sendbuf, sendcount, sendtype, root, system_tag, comm);
   } else {
-    sendsize = smpi_datatype_size(sendtype);
+    // FIXME: check for errors
+    smpi_datatype_extent(recvtype, &lb, &recvext);
     // Local copy from root
-    memcpy(&((char *) recvbuf)[displs[root]], sendbuf,
-           sendcount * sendsize * sizeof(char));
+    smpi_datatype_copy(sendbuf, sendcount, sendtype,
+                       (char *)recvbuf + displs[root] * recvext,
+                       recvcounts[root], recvtype);
     // 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_irecv_init(&((char *) recvbuf)[displs[src]],
-                            recvcounts[src], recvtype, src, system_tag,
-                            comm);
+          smpi_irecv_init((char *)recvbuf + displs[src] * recvext,
+                          recvcounts[src], recvtype, src, system_tag, comm);
         index++;
       }
     }
@@ -436,27 +693,28 @@ void smpi_mpi_allgather(void *sendbuf, int sendcount,
                         MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, other, index, sendsize, recvsize;
+  int rank, size, other, index;
+  MPI_Aint lb = 0, recvext = 0;
   MPI_Request *requests;
 
   rank = smpi_comm_rank(comm);
   size = smpi_comm_size(comm);
-  sendsize = smpi_datatype_size(sendtype);
-  recvsize = smpi_datatype_size(recvtype);
+  // FIXME: check for errors
+  smpi_datatype_extent(recvtype, &lb, &recvext);
   // Local copy from self
-  memcpy(&((char *) recvbuf)[rank * recvcount * recvsize], sendbuf,
-         sendcount * sendsize * sizeof(char));
+  smpi_datatype_copy(sendbuf, sendcount, sendtype,
+                     (char *)recvbuf + rank * recvcount * recvext, recvcount,
+                     recvtype);
   // 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_isend_init(sendbuf, sendcount, sendtype, other, system_tag,
-                          comm);
+        smpi_isend_init(sendbuf, sendcount, sendtype, other, system_tag,
+                        comm);
       index++;
-      requests[index] = smpi_irecv_init(&((char *) recvbuf)
-                                        [other * recvcount * recvsize],
+      requests[index] = smpi_irecv_init((char *)recvbuf + other * recvcount * recvext,
                                         recvcount, recvtype, other,
                                         system_tag, comm);
       index++;
@@ -474,29 +732,30 @@ void smpi_mpi_allgatherv(void *sendbuf, int sendcount,
                          MPI_Datatype recvtype, MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, other, index, sendsize, recvsize;
+  int rank, size, other, index;
+  MPI_Aint lb = 0, recvext = 0;
   MPI_Request *requests;
 
   rank = smpi_comm_rank(comm);
   size = smpi_comm_size(comm);
-  sendsize = smpi_datatype_size(sendtype);
-  recvsize = smpi_datatype_size(recvtype);
+  // FIXME: check for errors
+  smpi_datatype_extent(recvtype, &lb, &recvext);
   // Local copy from self
-  memcpy(&((char *) recvbuf)[displs[rank]], sendbuf,
-         sendcount * sendsize * sizeof(char));
+  smpi_datatype_copy(sendbuf, sendcount, sendtype,
+                     (char *)recvbuf + displs[rank] * recvext,
+                     recvcounts[rank], recvtype);
   // 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_isend_init(sendbuf, sendcount, sendtype, other, system_tag,
-                          comm);
+        smpi_isend_init(sendbuf, sendcount, sendtype, other, system_tag,
+                        comm);
       index++;
       requests[index] =
-          smpi_irecv_init(&((char *) recvbuf)[displs[other]],
-                          recvcounts[other], recvtype, other, system_tag,
-                          comm);
+        smpi_irecv_init((char *)recvbuf + displs[other] * recvext, recvcounts[other],
+                        recvtype, other, system_tag, comm);
       index++;
     }
   }
@@ -511,7 +770,8 @@ void smpi_mpi_scatter(void *sendbuf, int sendcount, MPI_Datatype sendtype,
                       int root, MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, dst, index, sendsize, recvsize;
+  int rank, size, dst, index;
+  MPI_Aint lb = 0, sendext = 0;
   MPI_Request *requests;
 
   rank = smpi_comm_rank(comm);
@@ -521,18 +781,17 @@ void smpi_mpi_scatter(void *sendbuf, int sendcount, MPI_Datatype sendtype,
     smpi_mpi_recv(recvbuf, recvcount, recvtype, root, system_tag, comm,
                   MPI_STATUS_IGNORE);
   } else {
-    sendsize = smpi_datatype_size(sendtype);
-    recvsize = smpi_datatype_size(recvtype);
+    // FIXME: check for errors
+    smpi_datatype_extent(sendtype, &lb, &sendext);
     // Local copy from root
-    memcpy(recvbuf, &((char *) sendbuf)[root * sendcount * sendsize],
-           recvcount * recvsize * sizeof(char));
+    smpi_datatype_copy((char *)sendbuf + root * sendcount * sendext,
+                       sendcount, sendtype, recvbuf, recvcount, recvtype);
     // 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_isend_init(&((char *) sendbuf)
-                                          [dst * sendcount * sendsize],
+        requests[index] = smpi_isend_init((char *)sendbuf + dst * sendcount * sendext,
                                           sendcount, sendtype, dst,
                                           system_tag, comm);
         index++;
@@ -550,7 +809,8 @@ void smpi_mpi_scatterv(void *sendbuf, int *sendcounts, int *displs,
                        MPI_Datatype recvtype, int root, MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, dst, index, sendsize, recvsize;
+  int rank, size, dst, index;
+  MPI_Aint lb = 0, sendext = 0;
   MPI_Request *requests;
 
   rank = smpi_comm_rank(comm);
@@ -560,20 +820,19 @@ void smpi_mpi_scatterv(void *sendbuf, int *sendcounts, int *displs,
     smpi_mpi_recv(recvbuf, recvcount, recvtype, root, system_tag, comm,
                   MPI_STATUS_IGNORE);
   } else {
-    sendsize = smpi_datatype_size(sendtype);
-    recvsize = smpi_datatype_size(recvtype);
+    // FIXME: check for errors
+    smpi_datatype_extent(sendtype, &lb, &sendext);
     // Local copy from root
-    memcpy(recvbuf, &((char *) sendbuf)[displs[root]],
-           recvcount * recvsize * sizeof(char));
+    smpi_datatype_copy((char *)sendbuf + displs[root] * sendext, sendcounts[root],
+                       sendtype, recvbuf, recvcount, recvtype);
     // 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_isend_init(&((char *) sendbuf)[displs[dst]],
-                            sendcounts[dst], sendtype, dst, system_tag,
-                            comm);
+          smpi_isend_init((char *)sendbuf + displs[dst] * sendext, sendcounts[dst],
+                          sendtype, dst, system_tag, comm);
         index++;
       }
     }
@@ -589,7 +848,8 @@ void smpi_mpi_reduce(void *sendbuf, void *recvbuf, int count,
                      MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, src, index, datasize;
+  int rank, size, src, index;
+  MPI_Aint lb = 0, dataext = 0;
   MPI_Request *requests;
   void **tmpbufs;
 
@@ -599,9 +859,11 @@ void smpi_mpi_reduce(void *sendbuf, void *recvbuf, int count,
     // Send buffer to root
     smpi_mpi_send(sendbuf, count, datatype, root, system_tag, comm);
   } else {
-    datasize = smpi_datatype_size(datatype);
+    // FIXME: check for errors
+    smpi_datatype_extent(datatype, &lb, &dataext);
     // Local copy from root
-    memcpy(recvbuf, sendbuf, count * datasize * sizeof(char));
+    if (sendbuf && recvbuf)
+      smpi_datatype_copy(sendbuf, count, datatype, recvbuf, count, datatype);
     // Receive buffers from senders
     //TODO: make a MPI_barrier here ?
     requests = xbt_new(MPI_Request, size - 1);
@@ -609,10 +871,12 @@ void smpi_mpi_reduce(void *sendbuf, void *recvbuf, int count,
     index = 0;
     for(src = 0; src < size; src++) {
       if(src != root) {
-        tmpbufs[index] = xbt_malloc(count * datasize);
+        // FIXME: possibly overkill we we have contiguous/noncontiguous data
+        //  mapping...
+        tmpbufs[index] = xbt_malloc(count * dataext);
         requests[index] =
-            smpi_irecv_init(tmpbufs[index], count, datatype, src,
-                            system_tag, comm);
+          smpi_irecv_init(tmpbufs[index], count, datatype, src,
+                          system_tag, comm);
         index++;
       }
     }
@@ -620,10 +884,12 @@ void smpi_mpi_reduce(void *sendbuf, void *recvbuf, int count,
     smpi_mpi_startall(size - 1, requests);
     for(src = 0; src < size - 1; src++) {
       index = smpi_mpi_waitany(size - 1, requests, MPI_STATUS_IGNORE);
+      XBT_DEBUG("finished waiting any request with index %d", index);
       if(index == MPI_UNDEFINED) {
         break;
       }
-      smpi_op_apply(op, tmpbufs[index], recvbuf, &count, &datatype);
+      if(op) /* op can be MPI_OP_NULL that does nothing */
+        smpi_op_apply(op, tmpbufs[index], recvbuf, &count, &datatype);
     }
     for(index = 0; index < size - 1; index++) {
       xbt_free(tmpbufs[index]);
@@ -638,86 +904,47 @@ void smpi_mpi_allreduce(void *sendbuf, void *recvbuf, int count,
 {
   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);
-*/
 }
 
 void smpi_mpi_scan(void *sendbuf, void *recvbuf, int count,
                    MPI_Datatype datatype, MPI_Op op, MPI_Comm comm)
 {
   int system_tag = 666;
-  int rank, size, other, index, datasize;
-  int total;
+  int rank, size, other, index;
+  MPI_Aint lb = 0, dataext = 0;
   MPI_Request *requests;
   void **tmpbufs;
 
   rank = smpi_comm_rank(comm);
   size = smpi_comm_size(comm);
-  datasize = smpi_datatype_size(datatype);
+
+  // FIXME: check for errors
+  smpi_datatype_extent(datatype, &lb, &dataext);
+
   // Local copy from self
-  memcpy(recvbuf, sendbuf, count * datasize * sizeof(char));
+  smpi_datatype_copy(sendbuf, count, datatype, recvbuf, count, datatype);
+
   // Send/Recv buffers to/from others;
-  total = rank + (size - (rank + 1));
-  requests = xbt_new(MPI_Request, total);
+  requests = xbt_new(MPI_Request, size - 1);
   tmpbufs = xbt_new(void *, rank);
   index = 0;
   for(other = 0; other < rank; other++) {
-    tmpbufs[index] = xbt_malloc(count * datasize);
+    // FIXME: possibly overkill we we have contiguous/noncontiguous data
+    // mapping...
+    tmpbufs[index] = xbt_malloc(count * dataext);
     requests[index] =
-        smpi_irecv_init(tmpbufs[index], count, datatype, other, system_tag,
-                        comm);
+      smpi_irecv_init(tmpbufs[index], count, datatype, other, system_tag,
+                      comm);
     index++;
   }
   for(other = rank + 1; other < size; other++) {
     requests[index] =
-        smpi_isend_init(sendbuf, count, datatype, other, system_tag, comm);
+      smpi_isend_init(sendbuf, count, datatype, other, system_tag, comm);
     index++;
   }
   // Wait for completion of all comms.
   smpi_mpi_startall(size - 1, requests);
-  for(other = 0; other < total; other++) {
+  for(other = 0; other < size - 1; other++) {
     index = smpi_mpi_waitany(size - 1, requests, MPI_STATUS_IGNORE);
     if(index == MPI_UNDEFINED) {
       break;
@@ -727,7 +954,7 @@ void smpi_mpi_scan(void *sendbuf, void *recvbuf, int count,
       smpi_op_apply(op, tmpbufs[index], recvbuf, &count, &datatype);
     }
   }
-  for(index = 0; index < size - 1; index++) {
+  for(index = 0; index < rank; index++) {
     xbt_free(tmpbufs[index]);
   }
   xbt_free(tmpbufs);