X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/863adae6473cc1fe177d0c48bc07b752beb83880..eca09d65271990fdae84e1d7da71916740a9c50b:/src/smpi/smpi_bench.c

diff --git a/src/smpi/smpi_bench.c b/src/smpi/smpi_bench.c
index 72230dba95..26f7c542ee 100644
--- a/src/smpi/smpi_bench.c
+++ b/src/smpi/smpi_bench.c
@@ -753,8 +753,25 @@ void smpi_initialize_global_memory_segments(){
       int status;
 
       int file_descriptor= mkstemp (path);
-      if (file_descriptor < 0)
-        xbt_die("Impossible to create temporary file for memory mapping");
+      if (file_descriptor < 0) {
+    	  if (errno==EMFILE) {
+    		  xbt_die("Impossible to create temporary file for memory mapping: %s\n\
+The open() system call failed with the EMFILE error code (too many files). \n\n\
+This means that you reached the system limits concerning the amount of files per process. \
+This is not a surprise if you are trying to virtualize many processes on top of SMPI. \
+Don't panic -- you should simply increase your system limits and try again. \n\n\
+First, check what your limits are:\n\
+  cat /proc/sys/fs/file-max # Gives you the system-wide limit\n\
+  ulimit -Hn                # Gives you the per process hard limit\n\
+  ulimit -Sn                # Gives you the per process soft limit\n\
+  cat /proc/self/limits     # Displays any per-process limitation (including the one given above)\n\n\
+If one of these values is less than the amount of MPI processes that you try to run, then you got the explanation of this error. \
+Ask the Internet about tutorials on how to increase the files limit such as: https://rtcamp.com/tutorials/linux/increase-open-files-limit/",
+             strerror(errno));
+    	  }
+        xbt_die("Impossible to create temporary file for memory mapping: %s",
+        		strerror(errno));
+      }
 
       status = unlink (path);
       if (status)