Add some clarifying comments about the variants

swiftmpirdmastepsim2.c

@@ -18,6 +18,7 @@
  ******************************************************************************/
 
 // Pure RDMA version, we use MPI for process control and synchronization.
+// Variation uses one sending thread and nranks receiving threads per rank.
 
 #include <arpa/inet.h>
 #include <limits.h>

swiftmpirdmastepsim3.c

@@ -18,6 +18,7 @@
  ******************************************************************************/
 
 // Pure RDMA version, we use MPI for process control and synchronization.
+// Variation uses one sending thread and one receiving thread per rank.
 
 #include <arpa/inet.h>
 #include <limits.h>