diff --git a/mps/code/eventdef.h b/mps/code/eventdef.h
index a0a368bd61e..e3a07a42118 100644
--- a/mps/code/eventdef.h
+++ b/mps/code/eventdef.h
@@ -744,7 +744,9 @@
 #define EVENT_GenInit_PARAMS(PARAM, X) \
   PARAM(X,  0, P, arena) /* arena owning generation */ \
   PARAM(X,  1, P, gen) /* the generation */ \
-  PARAM(X,  2, U, serial) /* serial number within arena */
+  PARAM(X,  2, U, serial) /* serial number within arena */ \
+  PARAM(X,  3, W, capacity) /* capacity in bytes */ \
+  PARAM(X,  4, D, mortality) /* initial mortality estimate */
 
 #define EVENT_GenFinish_PARAMS(PARAM, X) \
   PARAM(X,  0, P, arena) /* arena owning generation */ \
diff --git a/mps/code/locus.c b/mps/code/locus.c
index e8919b159fe..8e4e39e932e 100644
--- a/mps/code/locus.c
+++ b/mps/code/locus.c
@@ -123,6 +123,7 @@ static Bool GenParamCheck(GenParamStruct *params)
 {
   CHECKL(params != NULL);
   CHECKL(params->capacity > 0);
+  CHECKL(params->capacity <= SizeMAX / 1024);
   CHECKL(params->mortality >= 0.0);
   CHECKL(params->mortality <= 1.0);
   return TRUE;
@@ -139,13 +140,13 @@ static void GenDescInit(Arena arena, GenDesc gen, GenParamStruct *params)
   gen->serial = arena->genSerial;
   ++ arena->genSerial;
   gen->zones = ZoneSetEMPTY;
-  gen->capacity = params->capacity;
+  gen->capacity = params->capacity * 1024;
   gen->mortality = params->mortality;
   RingInit(&gen->locusRing);
   RingInit(&gen->segRing);
   gen->sig = GenDescSig;
   AVERT(GenDesc, gen);
-  EVENT3(GenInit, arena, gen, gen->serial);
+  EVENT5(GenInit, arena, gen, gen->serial, gen->capacity, gen->mortality);
 }
 
 
@@ -458,7 +459,7 @@ double ChainDeferral(Chain chain)
 
   if (chain->activeTraces == TraceSetEMPTY) {
     for (i = 0; i < chain->genCount; ++i) {
-      double genTime = chain->gens[i].capacity * 1024.0
+      double genTime = (double)chain->gens[i].capacity
         - (double)GenDescNewSize(&chain->gens[i]);
       if (genTime < time)
         time = genTime;
diff --git a/mps/code/locus.h b/mps/code/locus.h
index c558c9209ea..63e5cc39be9 100644
--- a/mps/code/locus.h
+++ b/mps/code/locus.h
@@ -43,8 +43,8 @@ typedef struct GenDescStruct {
   Sig sig;              /* <design/sig/> */
   Serial serial;        /* serial number within arena */
   ZoneSet zones;        /* zoneset for this generation */
-  Size capacity;        /* capacity in kB */
-  double mortality;     /* predicted mortality */
+  Size capacity;        /* capacity in bytes */
+  double mortality;     /* moving average mortality */
   RingStruct locusRing; /* Ring of all PoolGen's in this GenDesc (locus) */
   RingStruct segRing;   /* Ring of GCSegs in this generation */
   GenTraceStatsStruct trace[TraceLIMIT];
diff --git a/mps/code/policy.c b/mps/code/policy.c
index f89cceed4cb..a9c8099975e 100644
--- a/mps/code/policy.c
+++ b/mps/code/policy.c
@@ -232,7 +232,7 @@ static Res policyCondemnChain(double *mortalityReturn, Chain chain, Trace trace)
     gen = &chain->gens[topCondemnedGen];
     AVERT(GenDesc, gen);
     genNewSize = GenDescNewSize(gen);
-    if (genNewSize >= gen->capacity * (Size)1024)
+    if (genNewSize >= gen->capacity)
       break;
   }
 
diff --git a/mps/tool/monitor b/mps/tool/monitor
index f9a89300e7d..902d430b3be 100755
--- a/mps/tool/monitor
+++ b/mps/tool/monitor
@@ -310,6 +310,7 @@ class Gen(EventHandler):
         self._model.add_time_series(
             self, mortality_average, "fraction", f"mortality.avg",
             f"mortality of data in generation, moving average")
+        mortality_average.append(t, event.mortality);
         self._ref_size = ref_size = TimeSeries()
         self._model.add_time_series(
             self, ref_size, "bytes", f"ref",