diff --git a/mps/code/message.c b/mps/code/message.c
index 284e78c6314..ae7ba930616 100644
--- a/mps/code/message.c
+++ b/mps/code/message.c
@@ -284,6 +284,14 @@ MessageClass MessageGetClass(Message message)
   return message->class;
 }
 
+/* Return the class of a message */
+mps_clock_t MessageGetClock(Message message)
+{
+  AVERT(Message, message);
+
+  return message->postedClock;
+}
+
 static void MessageDelete(Message message)
 {
   AVERT(Message, message);
diff --git a/mps/code/mpm.h b/mps/code/mpm.h
index b9d8e7548c1..1dfa7dc2c6a 100644
--- a/mps/code/mpm.h
+++ b/mps/code/mpm.h
@@ -311,6 +311,7 @@ extern void MessageDiscard(Arena arena, Message message);
 /* -- Message Methods, Generic */
 extern MessageType MessageGetType(Message message);
 extern MessageClass MessageGetClass(Message message);
+extern mps_clock_t MessageGetClock(Message message);
 /* -- Message Method Dispatchers, Type-specific */
 extern void MessageFinalizationRef(Ref *refReturn,
                                    Arena arena, Message message);
diff --git a/mps/code/mpmst.h b/mps/code/mpmst.h
index 739c95a449d..1905e2bb560 100644
--- a/mps/code/mpmst.h
+++ b/mps/code/mpmst.h
@@ -223,6 +223,7 @@ typedef struct MessageStruct {
   MessageType type;             /* Message Type */
   MessageClass class;           /* Message Class Structure */
   RingStruct queueRing;         /* Message queue ring */
+  mps_clock_t postedClock;      /* mps_clock() at post time */
 } MessageStruct;
 
 
diff --git a/mps/code/mps.h b/mps/code/mps.h
index e47b88077c2..2852416bac8 100644
--- a/mps/code/mps.h
+++ b/mps/code/mps.h
@@ -48,6 +48,7 @@ typedef size_t mps_align_t;     /* alignment (size_t) */
 typedef unsigned mps_rm_t;      /* root mode (unsigned) */
 typedef unsigned mps_rank_t;    /* ranks (unsigned) */
 typedef unsigned mps_message_type_t;    /* message type (unsigned) */
+typedef unsigned long mps_clock_t;  /* processor time */
 
 /* Result Codes */
 /* .result-codes: Keep in sync with <code/mpmtypes.h#result-codes> */
@@ -527,6 +528,7 @@ extern void mps_message_discard(mps_arena_t, mps_message_t);
 
 /* -- All Message Types */
 extern mps_message_type_t mps_message_type(mps_arena_t, mps_message_t);
+extern mps_clock_t mps_message_clock(mps_arena_t, mps_message_t);
 
 /* -- mps_message_type_finalization */
 extern void mps_message_finalization_ref(mps_addr_t *,
diff --git a/mps/code/mpsi.c b/mps/code/mpsi.c
index 2dbc5cfe663..e5f88fc8541 100644
--- a/mps/code/mpsi.c
+++ b/mps/code/mpsi.c
@@ -1675,6 +1675,23 @@ mps_message_type_t mps_message_type(mps_arena_t mps_arena,
   return (mps_message_type_t)type;
 }
 
+mps_clock_t mps_message_clock(mps_arena_t mps_arena,
+                              mps_message_t mps_message)
+{
+  Arena arena = (Arena)mps_arena;
+  Message message = (Message)mps_message;
+  mps_clock_t postedClock;  /* @@@@ should be Clock, not mps_clock_t */
+
+  ArenaEnter(arena);
+
+  postedClock = MessageGetClock(message);
+
+  ArenaLeave(arena);
+
+  return (mps_clock_t)postedClock;
+}
+
+
 /* -- mps_message_type_finalization */
 
 void mps_message_finalization_ref(mps_addr_t *mps_addr_return,
diff --git a/mps/code/mpslib.h b/mps/code/mpslib.h
index 094975b3cf7..f74bd986fa6 100644
--- a/mps/code/mpslib.h
+++ b/mps/code/mpslib.h
@@ -14,7 +14,7 @@
 #define mpslib_h
 
 #include <stddef.h>
-
+#include "mps.h"  /* mps_clock_t */
 
 extern int mps_lib_get_EOF(void);
 #define mps_lib_EOF     (mps_lib_get_EOF())
@@ -36,7 +36,6 @@ extern void *(mps_lib_memcpy)(void *, const void *, size_t);
 extern int (mps_lib_memcmp)(const void *, const void *, size_t);
 
 
-typedef unsigned long mps_clock_t;
 extern mps_clock_t mps_clock(void);
 extern mps_clock_t mps_clocks_per_sec(void);