have smp-aware algorithms use number of cores on the node as basis for their computat...

[simgrid.git] / src / smpi / colls / allgather-smp-simple.c

diff --git a/src/smpi/colls/allgather-smp-simple.c b/src/smpi/colls/allgather-smp-simple.c
index f1c25d0..bd1206b 100644 (file)
--- a/src/smpi/colls/allgather-smp-simple.c
+++ b/src/smpi/colls/allgather-smp-simple.c
@@ -11,8 +11,13 @@ int smpi_coll_tuned_allgather_smp_simple(void *send_buf, int scount,
   int src, dst, comm_size, rank;
   comm_size = smpi_comm_size(comm);
 
-  if(comm_size%NUM_CORE)
-     THROWF(arg_error,0, "allgather SMP simple algorithm can't be used with non multiple of NUM_CORE=%d number of processes ! ", NUM_CORE);
+  int num_core = simcall_host_get_core(SIMIX_host_self());
+  // do we use the default one or the number of cores in the platform ?
+  // if the number of cores is one, the platform may be simulated with 1 node = 1 core
+  if (num_core == 1) num_core = NUM_CORE;
+
+  if(comm_size%num_core)
+     THROWF(arg_error,0, "allgather SMP simple algorithm can't be used with non multiple of NUM_CORE=%d number of processes ! ", num_core);
 
   rank = smpi_comm_rank(comm);
   MPI_Aint rextent, sextent;
@@ -22,7 +27,6 @@ int smpi_coll_tuned_allgather_smp_simple(void *send_buf, int scount,
   MPI_Status status;
   int i, send_offset, recv_offset;
   int intra_rank, inter_rank;
-  int num_core = NUM_CORE;
   intra_rank = rank % num_core;
   inter_rank = rank / num_core;
   int inter_comm_size = (comm_size + num_core - 1) / num_core;