diff --git a/src/mzscheme/src/eval.c b/src/mzscheme/src/eval.c
index a67fb259fa..08725e0da4 100644
--- a/src/mzscheme/src/eval.c
+++ b/src/mzscheme/src/eval.c
@@ -7860,13 +7860,7 @@ scheme_do_eval(Scheme_Object *obj, int num_rands, Scheme_Object **rands,
 
       f = prim->prim_val;
 
-      #ifdef FUTURES_ENABLED
-      LOG_PRIM_START(f);
-      #endif
       v = f(num_rands, rands, (Scheme_Object *)prim);
-      #ifdef FUTURES_ENABLED      
-      LOG_PRIM_END(f);
-      #endif
 
       DEBUG_CHECK_TYPE(v);
     } else if (type == scheme_closure_type) {
diff --git a/src/mzscheme/src/future.c b/src/mzscheme/src/future.c
index b10d589a2c..c6f8734664 100644
--- a/src/mzscheme/src/future.c
+++ b/src/mzscheme/src/future.c
@@ -468,43 +468,31 @@ void scheme_future_gc_pause()
 /* Primitive implementations                    					  */
 /**********************************************************************/
 
-static long start_ms = 0;
-
 Scheme_Object *start_primitive_tracking(int argc, Scheme_Object *argv[])
 {
-  //Get the start time
-  struct timeval now;
-  long ms;
-  gettimeofday(&now, NULL);
-	
-  start_ms = now.tv_usec / 1000.0;
-	
   g_print_prims = 1;
-  printf("Primitive tracking started at ");
-  print_ms_and_us();
-  printf("\n");
   return scheme_void;
 }
 
 Scheme_Object *end_primitive_tracking(int argc, Scheme_Object *argv[])
 {
   g_print_prims = 0;
-  printf("Primitive tracking ended at ");
-  print_ms_and_us();
-  printf("\n");
   return scheme_void;
 }
 
-void print_ms_and_us()
+void scheme_log_future_to_runtime(const char *who, void *p)
+/* Called in future thread */
 {
-  struct timeval now;
-  long ms, us;
-  gettimeofday(&now, NULL);
+  START_XFORM_SKIP;
 
-  //ms = (now.tv_sec * 1000.0) - start_ms;
-  ms = (now.tv_usec / 1000) - start_ms;
-  us = now.tv_usec - (ms * 1000) - (start_ms * 1000);
-  printf("%ld.%ld", ms, us);
+  if (g_print_prims) {
+    if (p)
+      fprintf(stderr, "%p at %lf\n", p, scheme_get_inexact_milliseconds());
+    else
+      fprintf(stderr, "%s at %lf\n", who, scheme_get_inexact_milliseconds());
+  }
+  
+  END_XFORM_SKIP;
 }
 
 Scheme_Object *future(int argc, Scheme_Object *argv[])
diff --git a/src/mzscheme/src/future.h b/src/mzscheme/src/future.h
index 2db66dfc7a..c0d7994a09 100644
--- a/src/mzscheme/src/future.h
+++ b/src/mzscheme/src/future.h
@@ -119,33 +119,12 @@ extern void clear_futures(void);
 #endif
 
 //Primitive instrumentation stuff 
-extern int g_print_prims;
-extern void print_ms_and_us(void);
-#define LOG_PRIM_START(p) \
-	if (g_print_prims) \
-	{ \
-		printf("%p ", p); \
-		print_ms_and_us(); \
-		printf("\n"); \
-	} 
 
-#define LOG_PRIM_END(p) 
-/*
-#define LOG_PRIM_END(p) \
-	if (g_print_prims) \
-	{ \
-		print_ms_and_us(); \
-		printf("\n"); \
-	}
-*/
-
-#define LOG_PRIM_W_NAME(name) \
-	if (g_print_prims) \
-	{ \
-		printf("%s ", name); \
-		print_ms_and_us(); \
-		printf("\n"); \
-	} 
+extern void scheme_log_future_to_runtime(const char *who, void *addr);
+#define LOG_PRIM_START(p) scheme_log_future_to_runtime(# p, NULL)
+#define LOG_PRIM_END(p) /* empty */
+#define LOG_PRIM_W_NAME(name) scheme_log_future_to_runtime(name, NULL)
+#define LOG_PRIM_W_ADDR(addr) scheme_log_future_to_runtime(NULL, addr)
 
 //Signature flags for primitive invocations
 //Here the convention is SIG_[arg1type]_[arg2type]..._[return type]
diff --git a/src/mzscheme/src/gen-jit-ts.ss b/src/mzscheme/src/gen-jit-ts.ss
index e7413ce057..e8b102bc98 100644
--- a/src/mzscheme/src/gen-jit-ts.ss
+++ b/src/mzscheme/src/gen-jit-ts.ss
@@ -43,10 +43,10 @@
      static @|result-type| ts_ ## id(@|args|) \
      { \
        START_XFORM_SKIP; \
-       LOG_PRIM_START(&id); \
-       if (scheme_use_rtcall) \
+       if (scheme_use_rtcall) { \
+         LOG_PRIM_START(id); \
          @|return| scheme_rtcall_@|t|(id, @(string-join arg-names ", ")); \
-       else \
+       } else \
          @|return| id(@(string-join arg-names ", ")); \
        END_XFORM_SKIP; \
      }})
diff --git a/src/mzscheme/src/jit.c b/src/mzscheme/src/jit.c
index 413b4e8db7..d61b91d4cc 100644
--- a/src/mzscheme/src/jit.c
+++ b/src/mzscheme/src/jit.c
@@ -2168,11 +2168,12 @@ static Scheme_Object *noncm_prim_indirect(Scheme_Prim proc, int argc)
 {
   START_XFORM_SKIP;
 
-  if (scheme_use_rtcall)
+  if (scheme_use_rtcall) {
+    LOG_PRIM_W_ADDR(proc);
     return scheme_rtcall_iS_s(proc, 
                               argc, 
                               MZ_RUNSTACK);
-  else 
+  } else 
     return proc(argc, MZ_RUNSTACK);
 
   END_XFORM_SKIP;
@@ -2181,9 +2182,10 @@ static Scheme_Object *prim_indirect(Scheme_Primitive_Closure_Proc proc, int argc
 {
   START_XFORM_SKIP;
 
-  if (scheme_use_rtcall)
+  if (scheme_use_rtcall) {
+    LOG_PRIM_W_ADDR(proc);
     return scheme_rtcall_iSs_s(proc, argc, MZ_RUNSTACK, self);
-  else
+  } else
     return proc(argc, MZ_RUNSTACK, self);
 
   END_XFORM_SKIP;
@@ -2196,9 +2198,10 @@ static Scheme_Object *prim_indirect(Scheme_Primitive_Closure_Proc proc, int argc
 static void ts_on_demand(void)
 {
   START_XFORM_SKIP;
-  if (scheme_use_rtcall)
+  if (scheme_use_rtcall) {
+    LOG_PRIM_START(on_demand);
     rtcall_void_void_3args(on_demand_with_args);
-  else
+  } else
     on_demand();
   END_XFORM_SKIP;
 }
@@ -2208,9 +2211,9 @@ static void *ts_prepare_retry_alloc(void *p, void *p2)
 {
   START_XFORM_SKIP;
   void *ret;
-  LOG_PRIM_START(&prepare_retry_alloc);
 
   if (scheme_use_rtcall) {
+    LOG_PRIM_START(prepare_retry_alloc);
     jit_future_storage[0] = p;
     jit_future_storage[1] = p2;
     ret = rtcall_alloc_void_pvoid(GC_make_jit_nursery_page);
diff --git a/src/mzscheme/src/jit_ts_def.c b/src/mzscheme/src/jit_ts_def.c
index 838dadf60d..d606a61223 100644
--- a/src/mzscheme/src/jit_ts_def.c
+++ b/src/mzscheme/src/jit_ts_def.c
@@ -2,10 +2,10 @@
 static Scheme_Object* ts_ ## id(Scheme_Object* g7, int g8, Scheme_Object** g9) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_siS_s(id, g7, g8, g9); \
-  else \
+  } else \
     return id(g7, g8, g9); \
   END_XFORM_SKIP; \
 }
@@ -13,10 +13,10 @@ static Scheme_Object* ts_ ## id(Scheme_Object* g7, int g8, Scheme_Object** g9) \
 static Scheme_Object* ts_ ## id(int g10, Scheme_Object** g11, Scheme_Object* g12) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_iSs_s(id, g10, g11, g12); \
-  else \
+  } else \
     return id(g10, g11, g12); \
   END_XFORM_SKIP; \
 }
@@ -24,10 +24,10 @@ static Scheme_Object* ts_ ## id(int g10, Scheme_Object** g11, Scheme_Object* g12
 static Scheme_Object* ts_ ## id(Scheme_Object* g13) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_s_s(id, g13); \
-  else \
+  } else \
     return id(g13); \
   END_XFORM_SKIP; \
 }
@@ -35,10 +35,10 @@ static Scheme_Object* ts_ ## id(Scheme_Object* g13) \
 static Scheme_Object* ts_ ## id(Scheme_Native_Closure_Data* g14) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_n_s(id, g14); \
-  else \
+  } else \
     return id(g14); \
   END_XFORM_SKIP; \
 }
@@ -46,10 +46,10 @@ static Scheme_Object* ts_ ## id(Scheme_Native_Closure_Data* g14) \
 static Scheme_Object* ts_ ## id() \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall__s(id, ); \
-  else \
+  } else \
     return id(); \
   END_XFORM_SKIP; \
 }
@@ -57,10 +57,10 @@ static Scheme_Object* ts_ ## id() \
 static Scheme_Object* ts_ ## id(Scheme_Object* g15, Scheme_Object* g16) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_ss_s(id, g15, g16); \
-  else \
+  } else \
     return id(g15, g16); \
   END_XFORM_SKIP; \
 }
@@ -68,10 +68,10 @@ static Scheme_Object* ts_ ## id(Scheme_Object* g15, Scheme_Object* g16) \
 static MZ_MARK_STACK_TYPE ts_ ## id(Scheme_Object* g17, Scheme_Object* g18) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_ss_m(id, g17, g18); \
-  else \
+  } else \
     return id(g17, g18); \
   END_XFORM_SKIP; \
 }
@@ -79,10 +79,10 @@ static MZ_MARK_STACK_TYPE ts_ ## id(Scheme_Object* g17, Scheme_Object* g18) \
 static Scheme_Object* ts_ ## id(Scheme_Object** g19, long g20) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_Sl_s(id, g19, g20); \
-  else \
+  } else \
     return id(g19, g20); \
   END_XFORM_SKIP; \
 }
@@ -90,10 +90,10 @@ static Scheme_Object* ts_ ## id(Scheme_Object** g19, long g20) \
 static Scheme_Object* ts_ ## id(long g21) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_l_s(id, g21); \
-  else \
+  } else \
     return id(g21); \
   END_XFORM_SKIP; \
 }
@@ -101,10 +101,10 @@ static Scheme_Object* ts_ ## id(long g21) \
 static void ts_ ## id(Scheme_Bucket* g22, Scheme_Object* g23, int g24) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
      scheme_rtcall_bsi_v(id, g22, g23, g24); \
-  else \
+  } else \
      id(g22, g23, g24); \
   END_XFORM_SKIP; \
 }
@@ -112,10 +112,10 @@ static void ts_ ## id(Scheme_Bucket* g22, Scheme_Object* g23, int g24) \
 static void ts_ ## id(int g25, int g26, Scheme_Object** g27) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
      scheme_rtcall_iiS_v(id, g25, g26, g27); \
-  else \
+  } else \
      id(g25, g26, g27); \
   END_XFORM_SKIP; \
 }
@@ -123,10 +123,10 @@ static void ts_ ## id(int g25, int g26, Scheme_Object** g27) \
 static void ts_ ## id(Scheme_Object* g28, Scheme_Object* g29) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
      scheme_rtcall_ss_v(id, g28, g29); \
-  else \
+  } else \
      id(g28, g29); \
   END_XFORM_SKIP; \
 }
@@ -134,10 +134,10 @@ static void ts_ ## id(Scheme_Object* g28, Scheme_Object* g29) \
 static void ts_ ## id(Scheme_Bucket* g30) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
      scheme_rtcall_b_v(id, g30); \
-  else \
+  } else \
      id(g30); \
   END_XFORM_SKIP; \
 }
@@ -145,10 +145,10 @@ static void ts_ ## id(Scheme_Bucket* g30) \
 static Scheme_Object* ts_ ## id(Scheme_Object* g31, long g32) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_sl_s(id, g31, g32); \
-  else \
+  } else \
     return id(g31, g32); \
   END_XFORM_SKIP; \
 }
@@ -156,10 +156,10 @@ static Scheme_Object* ts_ ## id(Scheme_Object* g31, long g32) \
 static Scheme_Object* ts_ ## id(int g33, Scheme_Object** g34) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_iS_s(id, g33, g34); \
-  else \
+  } else \
     return id(g33, g34); \
   END_XFORM_SKIP; \
 }
@@ -167,10 +167,10 @@ static Scheme_Object* ts_ ## id(int g33, Scheme_Object** g34) \
 static Scheme_Object* ts_ ## id(Scheme_Object** g35) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_S_s(id, g35); \
-  else \
+  } else \
     return id(g35); \
   END_XFORM_SKIP; \
 }
@@ -178,10 +178,10 @@ static Scheme_Object* ts_ ## id(Scheme_Object** g35) \
 static void ts_ ## id(Scheme_Object* g36) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
      scheme_rtcall_s_v(id, g36); \
-  else \
+  } else \
      id(g36); \
   END_XFORM_SKIP; \
 }
@@ -189,10 +189,10 @@ static void ts_ ## id(Scheme_Object* g36) \
 static Scheme_Object* ts_ ## id(int g37, Scheme_Object** g38, int g39) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_iSi_s(id, g37, g38, g39); \
-  else \
+  } else \
     return id(g37, g38, g39); \
   END_XFORM_SKIP; \
 }
@@ -200,10 +200,10 @@ static Scheme_Object* ts_ ## id(int g37, Scheme_Object** g38, int g39) \
 static void ts_ ## id(Scheme_Object* g40, int g41, Scheme_Object** g42) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
      scheme_rtcall_siS_v(id, g40, g41, g42); \
-  else \
+  } else \
      id(g40, g41, g42); \
   END_XFORM_SKIP; \
 }
@@ -211,10 +211,10 @@ static void ts_ ## id(Scheme_Object* g40, int g41, Scheme_Object** g42) \
 static void* ts_ ## id(size_t g43) \
 { \
   START_XFORM_SKIP; \
-  LOG_PRIM_START(&id); \
-  if (scheme_use_rtcall) \
+  if (scheme_use_rtcall) { \
+    LOG_PRIM_START(id); \
     return scheme_rtcall_z_p(id, g43); \
-  else \
+  } else \
     return id(g43); \
   END_XFORM_SKIP; \
 }
diff --git a/src/mzscheme/src/schnapp.inc b/src/mzscheme/src/schnapp.inc
index 57f1e38441..c045d7ef66 100644
--- a/src/mzscheme/src/schnapp.inc
+++ b/src/mzscheme/src/schnapp.inc
@@ -31,13 +31,7 @@ static MZ_INLINE Scheme_Object *PRIM_APPLY_NAME_FAST(Scheme_Object *rator,
   }
   
   f = (Scheme_Primitive_Closure_Proc *)prim->prim_val;
-  #ifdef FUTURES_ENABLED
-  LOG_PRIM_START(f);
-  #endif
   v = f(argc, argv, (Scheme_Object *)prim);
-  #ifdef FUTURES_ENABLED  
-  LOG_PRIM_END(f);  
-  #endif
 
 #if PRIM_CHECK_VALUE
   if (v == SCHEME_TAIL_CALL_WAITING) {