diff --git a/swiftmpirdmastepsim2.c b/swiftmpirdmastepsim2.c
index c262f687e0bdbfb5d08af7a30ecb4ca1a57c5051..88d8c447ccb16f2f6aee38cd871b02b95509d15c 100644
--- a/swiftmpirdmastepsim2.c
+++ b/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>
diff --git a/swiftmpirdmastepsim3.c b/swiftmpirdmastepsim3.c
index 207be924be1f12d6fe7a0b1ed976ac41faf0d28b..ecd85218c6e1b6fe9ea8b14fb7819db83bc2e30a 100644
--- a/swiftmpirdmastepsim3.c
+++ b/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>