X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/6c12a132ca10eefd1d566e489e837e459db4d979..55eda6695068477d25d74cfa9335f79ad5a9b826:/src/smpi/smpi_base.c

diff --git a/src/smpi/smpi_base.c b/src/smpi/smpi_base.c
index c75e51dabf..84edb27fe1 100644
--- a/src/smpi/smpi_base.c
+++ b/src/smpi/smpi_base.c
@@ -7,6 +7,7 @@
 #include "private.h"
 #include "xbt/virtu.h"
 #include "mc/mc.h"
+#include "mc/mc_replay.h"
 #include "xbt/replay.h"
 #include <errno.h>
 #include "simix/smx_private.h"
@@ -195,7 +196,12 @@ double smpi_mpi_wtime(){
   if (smpi_process_initialized() && !smpi_process_finalized() && !smpi_process_get_sampling()) {
     smpi_bench_end();
     time = SIMIX_get_clock();
-    //to avoid deadlocks if called too many times
+    // to avoid deadlocks if used as a break condition, such as
+    //     while (MPI_Wtime(...) < time_limit) {
+    //       ....
+    //     }
+    // because the time will not normally advance when only calls to MPI_Wtime
+    // are made -> deadlock (MPI_Wtime never reaches the time limit)
     if(smpi_wtime_sleep > 0) simcall_process_sleep(smpi_wtime_sleep);
     smpi_bench_begin();
   } else {
@@ -743,8 +749,12 @@ int smpi_mpi_test(MPI_Request * request, MPI_Status * status) {
 
   //assume that request is not MPI_REQUEST_NULL (filtered in PMPI_Test or smpi_mpi_testall before)
 
-  //to avoid deadlocks
-  //multiplier to the sleeptime, to increase speed of execution, each failed test will increase it
+  // to avoid deadlocks if used as a break condition, such as
+  //     while (MPI_Test(request, flag, status) && flag) {
+  //     }
+  // because the time will not normally advance when only calls to MPI_Test
+  // are made -> deadlock
+  // multiplier to the sleeptime, to increase speed of execution, each failed test will increase it
   static int nsleeps = 1;
   if(smpi_test_sleep > 0)  simcall_process_sleep(nsleeps*smpi_test_sleep);
 
@@ -853,8 +863,9 @@ 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 == MPI_ANY_SOURCE ? MPI_ANY_SOURCE : smpi_group_index(smpi_comm_group(comm), source), smpi_comm_rank(comm), tag,
             comm, 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
-  //multiplier to the sleeptime, to increase speed of execution, each failed iprobe will increase it
+  // to avoid deadlock, we have to sleep some time here, or the timer won't advance and we will only do iprobe simcalls
+  // (especially when used as a break condition, such as while(MPI_Iprobe(...)) ... )
+  // multiplier to the sleeptime, to increase speed of execution, each failed iprobe will increase it
   static int nsleeps = 1;
   if(smpi_iprobe_sleep > 0)  simcall_process_sleep(nsleeps*smpi_iprobe_sleep);
   // behave like a receive, but don't do it
@@ -862,31 +873,31 @@ void smpi_mpi_iprobe(int source, int tag, MPI_Comm comm, int* flag, MPI_Status*
 
   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 (sg_cfg_get_int("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, 0, 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, 0, request->src,request->tag, &match_recv, (void*)request);
-    }
+  if (sg_cfg_get_int("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, 0, 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, 0, request->src,request->tag, &match_recv, (void*)request);
+  }
 
-  if(request->action){
+  if (request->action){
     MPI_Request req = (MPI_Request)SIMIX_comm_get_src_data(request->action);
     *flag = 1;
     if(status != MPI_STATUS_IGNORE && !(req->flags & PREPARED)) {
       status->MPI_SOURCE = smpi_group_rank(smpi_comm_group(comm), req->src);
-      status->MPI_TAG = req->tag;
-      status->MPI_ERROR = MPI_SUCCESS;
-      status->count = req->real_size;
+      status->MPI_TAG    = req->tag;
+      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++;
+    *flag = 0;
+    nsleeps++;
   }
   smpi_mpi_request_free(&request);