add an option smpi/iprobe, to inject sleeping time into a MPI_Iprobe call.

[simgrid.git] / src / smpi / smpi_base.c

diff --git a/src/smpi/smpi_base.c b/src/smpi/smpi_base.c
index 6ffe7f6..330bcc9 100644 (file)
--- a/src/smpi/smpi_base.c
+++ b/src/smpi/smpi_base.c
@@ -197,7 +197,7 @@ static MPI_Request build_request(void *buf, int count,
   if(datatype->has_subtype == 1){
     // This part handles the problem of non-contiguous memory
     old_buf = buf;
-    buf = xbt_malloc(count*smpi_datatype_size(datatype));
+    buf = count==0 ? NULL : xbt_malloc(count*smpi_datatype_size(datatype));
     if (flags & SEND) {
       subtype->serialize(old_buf, buf, count, datatype->substruct);
     }
@@ -369,6 +369,7 @@ void smpi_mpi_start(MPI_Request request)
       }
       XBT_DEBUG("Send request %p is detached; buf %p copied into %p",request,oldbuf,request->buf);
     }
+
     // we make a copy here, as the size is modified by simix, and we may reuse the request in another receive later
     request->real_size=request->size;
     smpi_datatype_use(request->old_type);
@@ -508,8 +509,11 @@ void smpi_mpi_send(void *buf, int count, MPI_Datatype datatype, int dst,
 void smpi_mpi_ssend(void *buf, int count, MPI_Datatype datatype,
                            int dst, int tag, MPI_Comm comm)
 {
-  MPI_Request request = smpi_mpi_issend(buf, count, datatype, dst, tag, comm);
-  smpi_mpi_wait(&request, MPI_STATUS_IGNORE);
+  MPI_Request request =
+      build_request(buf, count, datatype, smpi_comm_rank(comm), dst, tag,
+                    comm, NON_PERSISTENT | SSEND | SEND);
+
+  smpi_mpi_start(request);  smpi_mpi_wait(&request, MPI_STATUS_IGNORE);
 }
 
 void smpi_mpi_sendrecv(void *sendbuf, int sendcount, MPI_Datatype sendtype,
@@ -678,9 +682,6 @@ void smpi_mpi_probe(int source, int tag, MPI_Comm comm, MPI_Status* status){
   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);
-    }
   }
 }
 
@@ -688,6 +689,13 @@ void smpi_mpi_iprobe(int source, int tag, MPI_Comm comm, int* flag, MPI_Status*
   MPI_Request request =build_request(NULL, 0, MPI_CHAR, source, smpi_comm_rank(comm), tag,
             comm, NON_PERSISTENT | RECV);
 
+  //to avoid deadlock, we have to sleep some time here, or the timer won't advance and we will only do iprobe simcalls
+  double sleeptime= sg_cfg_get_double("smpi/iprobe");
+  //multiplier to the sleeptime, to increase speed of execution, each failed iprobe will increase it
+  static int nsleeps = 1;
+
+  simcall_process_sleep(sleeptime);
+
   // behave like a receive, but don't do it
   smx_rdv_t mailbox;
 
@@ -713,8 +721,12 @@ void smpi_mpi_iprobe(int source, int tag, MPI_Comm comm, int* flag, MPI_Status*
       status->MPI_ERROR = MPI_SUCCESS;
       status->count = req->real_size;
     }
+    nsleeps=1;//reset the number of sleeps we will do next time
+  }
+  else {
+      *flag = 0;
+      nsleeps++;
   }
-  else *flag = 0;
   smpi_mpi_request_free(&request);
 
   return;