diff --git a/mps/code/eventdef.h b/mps/code/eventdef.h
index 225c21f5f65..cb7b590274c 100644
--- a/mps/code/eventdef.h
+++ b/mps/code/eventdef.h
@@ -655,7 +655,7 @@
 #define EVENT_ArenaPoll_PARAMS(PARAM, X) \
   PARAM(X,  0, P, arena) \
   PARAM(X,  1, W, start) \
-  PARAM(X,  2, W, quanta)
+  PARAM(X,  2, B, workWasDone)
 
 #define EVENT_ArenaSetEmergency_PARAMS(PARAM, X) \
   PARAM(X,  0, P, arena) \
diff --git a/mps/code/global.c b/mps/code/global.c
index d15e5cd0da7..d9a5bf9c6c7 100644
--- a/mps/code/global.c
+++ b/mps/code/global.c
@@ -704,7 +704,7 @@ void (ArenaPoll)(Globals globals)
 {
   Arena arena;
   Clock start;
-  Count quanta;
+  Bool moreWork, workWasDone = FALSE;
   Work tracedWork;
 
   AVERT(Globals, globals);
@@ -721,25 +721,24 @@ void (ArenaPoll)(Globals globals)
 
   /* fillMutatorSize has advanced; call TracePoll enough to catch up. */
   start = ClockNow();
-  quanta = 0;
 
-  EVENT3(ArenaPoll, arena, start, 0);
+  EVENT3(ArenaPoll, arena, start, FALSE);
 
   do {
-    tracedWork = TracePoll(globals);
-    if (tracedWork > 0) {
-      quanta += 1;
+    moreWork = TracePoll(&tracedWork, globals);
+    if (moreWork) {
+      workWasDone = TRUE;
     }
-  } while (PolicyPollAgain(arena, start, tracedWork));
+  } while (PolicyPollAgain(arena, moreWork, tracedWork));
 
   /* Don't count time spent checking for work, if there was no work to do. */
-  if(quanta > 0) {
+  if (workWasDone) {
     ArenaAccumulateTime(arena, start);
   }
 
   AVER(!PolicyPoll(arena));
 
-  EVENT3(ArenaPoll, arena, start, quanta);
+  EVENT3(ArenaPoll, arena, start, BOOLOF(workWasDone));
 
   globals->insidePoll = FALSE;
 }
@@ -780,7 +779,7 @@ static Bool arenaShouldCollectWorld(Arena arena,
 Bool ArenaStep(Globals globals, double interval, double multiplier)
 {
   Work work;
-  Bool stepped;
+  Bool moreWork, workWasDone = FALSE;
   Clock start, end, now;
   Clock clocks_per_sec;
   Arena arena;
@@ -796,8 +795,6 @@ Bool ArenaStep(Globals globals, double interval, double multiplier)
   end = start + (Clock)(interval * clocks_per_sec);
   AVER(end >= start);
 
-  stepped = FALSE;
-
   if (arenaShouldCollectWorld(arena, interval, multiplier,
                               start, clocks_per_sec))
   {
@@ -806,24 +803,24 @@ Bool ArenaStep(Globals globals, double interval, double multiplier)
     res = TraceStartCollectAll(&trace, arena, TraceStartWhyOPPORTUNISM);
     if (res == ResOK) {
       arena->lastWorldCollect = start;
-      stepped = TRUE;
+      workWasDone = TRUE;
     }
   }
 
   /* loop while there is work to do and time on the clock. */
   do {
-    work = TracePoll(globals);
+    moreWork = TracePoll(&work, globals);
     now = ClockNow();
-    if (work > 0) {
-      stepped = TRUE;
+    if (moreWork) {
+      workWasDone = TRUE;
     }
-  } while ((work > 0) && (now < end));
+  } while (moreWork && now < end);
 
-  if (stepped) {
+  if (workWasDone) {
     ArenaAccumulateTime(arena, start);
   }
 
-  return stepped;
+  return workWasDone;
 }
 
 /* ArenaFinalize -- registers an object for finalization
diff --git a/mps/code/mpm.h b/mps/code/mpm.h
index 3e888ad28de..ad8620b800f 100644
--- a/mps/code/mpm.h
+++ b/mps/code/mpm.h
@@ -399,7 +399,7 @@ extern void TraceDestroyFinished(Trace trace);
 extern Res TraceAddWhite(Trace trace, Seg seg);
 extern Res TraceCondemnZones(Trace trace, ZoneSet condemnedSet);
 extern Res TraceStart(Trace trace, double mortality, double finishingTime);
-extern Work TracePoll(Globals globals);
+extern Bool TracePoll(Work *workReturn, Globals globals);
 
 extern Rank TraceRankForAccess(Arena arena, Seg seg);
 extern void TraceSegAccess(Arena arena, Seg seg, AccessSet mode);
@@ -667,7 +667,7 @@ extern Res PolicyAlloc(Tract *tractReturn, Arena arena, LocusPref pref,
 extern Bool PolicyStartTrace(Trace *traceReturn, Arena arena);
 extern double PolicyCollectionTime(Arena arena);
 extern Bool PolicyPoll(Arena arena);
-extern Bool PolicyPollAgain(Arena arena, Clock start, Work tracedWork);
+extern Bool PolicyPollAgain(Arena arena, Bool moreWork, Work tracedWork);
 
 
 /* Locus interface */
diff --git a/mps/code/policy.c b/mps/code/policy.c
index e3c09c8d6d7..77f91ebacd0 100644
--- a/mps/code/policy.c
+++ b/mps/code/policy.c
@@ -309,20 +309,20 @@ Bool PolicyPoll(Arena arena)
  * should return to the mutator.
  *
  * start is the clock time when the MPS was entered.
- * tracedWork is the amount of work done by the last call to TracePoll.
+ * moreWork and tracedWork are the results of the last call to TracePoll.
  */
 
-Bool PolicyPollAgain(Arena arena, Clock start, Work tracedWork)
+Bool PolicyPollAgain(Arena arena, Bool moreWork, Work tracedWork)
 {
   Globals globals;
   double nextPollThreshold;
 
   AVERT(Arena, arena);
   globals = ArenaGlobals(arena);
-  UNUSED(start);
+  UNUSED(tracedWork);
   
-  if (tracedWork == 0) {
-    /* No work was done.  Sleep until NOW + a bit. */
+  if (!moreWork) {
+    /* No more work to do.  Sleep until NOW + a bit. */
     nextPollThreshold = globals->fillMutatorSize + ArenaPollALLOCTIME;
   } else {
     /* We did one quantum of work; consume one unit of 'time'. */
diff --git a/mps/code/trace.c b/mps/code/trace.c
index 378b6bed9a1..47bd74b8283 100644
--- a/mps/code/trace.c
+++ b/mps/code/trace.c
@@ -1846,10 +1846,12 @@ failCondemn:
 /* TracePoll -- Check if there's any tracing work to be done
  *
  * Consider starting a trace if none is running; advance the running
- * trace (if any) by one quantum. Return a measure of the work done.
+ * trace (if any) by one quantum. If there may be more work to do,
+ * update *workReturn with a measure of the work done and return TRUE.
+ * Otherwise return FALSE.
  */
 
-Work TracePoll(Globals globals)
+Bool TracePoll(Work *workReturn, Globals globals)
 {
   Trace trace;
   Arena arena;
@@ -1863,7 +1865,7 @@ Work TracePoll(Globals globals)
   } else {
     /* No traces are running: consider starting one now. */
     if (!PolicyStartTrace(&trace, arena))
-      return (Size)0;
+      return FALSE;
   }
 
   AVER(arena->busyTraces == TraceSetSingle(trace));
@@ -1877,7 +1879,8 @@ Work TracePoll(Globals globals)
   work = newWork - oldWork;
   if (trace->state == TraceFINISHED)
     TraceDestroyFinished(trace);
-  return work;
+  *workReturn = work;
+  return TRUE;
 }