diff --git a/src/hotspot/share/gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.cpp b/src/hotspot/share/gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.cpp
index ffcc27d25c7..a501d23ab72 100644
--- a/src/hotspot/share/gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.cpp
+++ b/src/hotspot/share/gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.cpp
@@ -341,6 +341,9 @@ double ShenandoahAdaptiveHeuristics::predict_mark_time(size_t anticipated_marked
 }
 
 double ShenandoahAdaptiveHeuristics::predict_evac_time(size_t anticipated_evac_words, size_t anticipated_pip_words) {
+  // The non-generational version of predict_evac_time() assumes no dependency on anticipated_pip_words,
+  // which should always equal zero.
+  assert(anticipate_pip_words == 0, "Non-generational mode has no promote in place");
   return _phase_stats[ShenandoahMajorGCPhase::_evac].predict_at((double) (5 * anticipated_evac_words));
 }
 
@@ -349,6 +352,8 @@ double ShenandoahAdaptiveHeuristics::predict_update_time(size_t anticipated_upda
 }
 
 double ShenandoahAdaptiveHeuristics::predict_final_roots_time(size_t pip_words) {
+  // The non-generational version of predict_final_roots_time() assumes constant time, since pip_words is always zero.
+  assert(pip_words == 0, "Non-generational mode has no promote in place");
   return _phase_stats[ShenandoahMajorGCPhase::_final_roots].predict_at((double) 0.0);
 }
 
diff --git a/src/hotspot/share/gc/shenandoah/heuristics/shenandoahYoungHeuristics.cpp b/src/hotspot/share/gc/shenandoah/heuristics/shenandoahYoungHeuristics.cpp
index 3a37d238455..00c985856d3 100644
--- a/src/hotspot/share/gc/shenandoah/heuristics/shenandoahYoungHeuristics.cpp
+++ b/src/hotspot/share/gc/shenandoah/heuristics/shenandoahYoungHeuristics.cpp
@@ -357,6 +357,22 @@ void ShenandoahYoungHeuristics:: update_anticipated_after_completed_gc(size_t ol
     // start of a bootstrap cycle, and will surge workers at that time if necessary.
     size_t anticipated_mark_words = get_young_live_words_after_most_recent_mark();
 
+    if (ShenandoahAllowOldMarkingPreemption || !next_cycle_is_bootstrap()) {
+      // This is the normal mode of operation.
+
+      // Words which recently became old due to promote-in-place, mixed-evacuation, or promotion by evacuation are
+      // conservatively flagged as dirty within the remembered set. The extra work required to clean this data during
+      // marking may result in much larger than normal times to scan the remembered set (e.g 714 ms vs 30 ms)
+      anticipated_mark_words = get_normal_young_mark_words() + get_recently_old_words();
+
+    } else {
+      // All Bootstrap GC cycles are Global cycles
+
+
+    }
+
+
+
     // We'll assume all promotion is by evacuation.  If we find out following mark that some of the promotion will be
     // in place, we will adjust anticipation there.  Assuming all promotion is by evacuation yields more conservative
     // approximation of GC time.