From: Augustin Degomme <adegomme@gmail.com>
Date: Thu, 9 May 2019 23:37:23 +0000 (+0200)
Subject: Don't use positive tags for internal messages.
X-Git-Tag: v3.22.4~127^2~40
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/bef10718ac2d3f0e44ef52ca18e699896fd50228

Don't use positive tags for internal messages.
They could interfere with receives posted with MPI_ANY_TAG in user's code
---

diff --git a/src/smpi/colls/bcast/bcast-arrival-scatter.cpp b/src/smpi/colls/bcast/bcast-arrival-scatter.cpp
index 7d51422f44..7891c76302 100644
--- a/src/smpi/colls/bcast/bcast-arrival-scatter.cpp
+++ b/src/smpi/colls/bcast/bcast-arrival-scatter.cpp
@@ -21,7 +21,7 @@ int Coll_bcast_arrival_scatter::bcast(void *buf, int count,
                                           MPI_Comm comm)
 {
   int tag = -COLL_TAG_BCAST;//in order to use ANY_TAG, make this one positive
-  int header_tag = 10;
+  int header_tag = -10;
   MPI_Status status;
 
   int curr_remainder;
diff --git a/src/smpi/mpi/smpi_comm.cpp b/src/smpi/mpi/smpi_comm.cpp
index 5bdf88d4f5..7f51e7e86c 100644
--- a/src/smpi/mpi/smpi_comm.cpp
+++ b/src/smpi/mpi/smpi_comm.cpp
@@ -212,7 +212,7 @@ MPI_Comm Comm::split(int color, int key)
 {
   if (this == MPI_COMM_UNINITIALIZED)
     return smpi_process()->comm_world()->split(color, key);
-  int system_tag = 123;
+  int system_tag = -123;
   int* recvbuf;
 
   MPI_Group group_root = nullptr;