diff --git a/kernel/lib_queue.h b/kernel/lib_queue.h
index 750f4ca8..56b86255 100644
--- a/kernel/lib_queue.h
+++ b/kernel/lib_queue.h
@@ -28,6 +28,7 @@
 #define QUEUE_ANCHOR(PREFIX,KEYTYPE,HEAPTYPE)				\
 	/* parameters */						\
 	/* readonly from outside */					\
+	int q_active;							\
 	int q_queued;							\
 	atomic_t q_flying;						\
 	/* tunables */							\
@@ -61,11 +62,23 @@ void q_##PREFIX##_init(struct PREFIX##_queue *q)			\
 	q->heap_low = NULL;						\
 	q->heap_high = NULL;						\
 	spin_lock_init(&q->q_lock);					\
+	q->q_active = 0;						\
 	q->q_queued = 0;						\
 	atomic_set(&q->q_flying, 0);					\
 }									\
 									\
 static inline							        \
+void __q_##PREFIX##_insert_ordered(struct PREFIX##_queue *q, ELEM_TYPE *elem) \
+{									\
+	struct pairing_heap_##HEAPTYPE **use = &q->heap_high;		\
+									\
+	if (KEYCMP(KEYFN(elem), &q->heap_margin) <= 0) {		\
+		use = &q->heap_low;					\
+	}								\
+	ph_insert_##HEAPTYPE(use, &elem->ph);				\
+}									\
+									\
+static inline							        \
 void q_##PREFIX##_insert(struct PREFIX##_queue *q, ELEM_TYPE *elem)	\
 {									\
 	unsigned long flags;						\
@@ -73,14 +86,11 @@ void q_##PREFIX##_insert(struct PREFIX##_queue *q, ELEM_TYPE *elem)	\
 	traced_lock(&q->q_lock, flags);					\
 									\
 	if (q->q_ordering) {						\
-		struct pairing_heap_##HEAPTYPE **use = &q->heap_high;	\
-		if (KEYCMP(KEYFN(elem), &q->heap_margin) <= 0) {	\
-			use = &q->heap_low;				\
-		}							\
-		ph_insert_##HEAPTYPE(use, &elem->ph);			\
+		__q_##PREFIX##_insert_ordered(q, elem);			\
 	} else {							\
 		list_add_tail(&elem->HEAD, &q->q_anchor);		\
 	}								\
+	q->q_active++;							\
 	q->q_queued++;							\
 	q->q_last_insert = jiffies;					\
 									\
@@ -94,17 +104,18 @@ void q_##PREFIX##_pushback(struct PREFIX##_queue *q, ELEM_TYPE *elem)	\
 {									\
 	unsigned long flags;						\
 									\
-	if (q->q_ordering) {						\
-		q_##PREFIX##_insert(q, elem);				\
-		return;							\
-	}								\
-									\
 	traced_lock(&q->q_lock, flags);					\
 									\
-	list_add(&elem->HEAD, &q->q_anchor);				\
+	if (q->q_ordering) {						\
+		__q_##PREFIX##_insert_ordered(q, elem);			\
+	} else {							\
+		list_add(&elem->HEAD, &q->q_anchor);			\
+	}								\
 	q->q_queued++;							\
 									\
 	traced_unlock(&q->q_lock, flags);				\
+									\
+	q_##PREFIX##_trigger(q);					\
 }									\
 									\
 static inline							        \
@@ -164,6 +175,16 @@ void q_##PREFIX##_dec_flying(struct PREFIX##_queue *q)			\
 	q_##PREFIX##_trigger(q);					\
 }									\
 									\
+static inline							        \
+void q_##PREFIX##_activate(struct PREFIX##_queue *q, int count)		\
+{									\
+	unsigned long flags;						\
+									\
+	traced_lock(&q->q_lock, flags);					\
+	q->q_active += count;						\
+	traced_unlock(&q->q_lock, flags);				\
+	q_##PREFIX##_trigger(q);					\
+}									\
 
 
 #endif
diff --git a/kernel/mars_trans_logger.c b/kernel/mars_trans_logger.c
index 3939e65b..d675b50a 100644
--- a/kernel/mars_trans_logger.c
+++ b/kernel/mars_trans_logger.c
@@ -218,6 +218,18 @@ void qq_dec_flying(struct logger_queue *q)
 	q_logger_dec_flying(q);
 }
 
+static inline
+void qq_activate(struct logger_queue *q)
+{
+	q_logger_activate(q, 1);
+}
+
+static inline
+void qq_deactivate(struct logger_queue *q)
+{
+	q_logger_activate(q, -1);
+}
+
 static inline
 void qq_mref_insert(struct logger_queue *q, struct trans_logger_mref_aspect *mref_a)
 {
@@ -1583,6 +1595,8 @@ void phase0_endio(void *private, int error)
 
 	banning_reset(&brick->q_phase[0].q_banning);
 
+	qq_deactivate(&brick->q_phase[0]);
+
 	wake_up_interruptible_all(&brick->worker_event);
 	return;
 err: 
@@ -1708,6 +1722,7 @@ bool prep_phase_startio(struct trans_logger_mref_aspect *mref_a)
 
 		__trans_logger_ref_put(brick, mref_a);
 
+		qq_deactivate(&brick->q_phase[0]);
 		return true;
 	} 
 	// else WRITE
@@ -1793,6 +1808,7 @@ void phase1_endio(struct generic_callback *cb)
 
 	// queue up for the next phase
 	qq_wb_insert(&brick->q_phase[2], wb);
+	qq_deactivate(&brick->q_phase[1]);
 	wake_up_interruptible_all(&brick->worker_event);
 	return;
 
@@ -1820,10 +1836,12 @@ bool phase1_startio(struct trans_logger_mref_aspect *orig_mref_a)
 
 	if (orig_mref_a->is_collected) {
 		MARS_IO("already collected, pos = %lld len = %d\n", orig_mref->ref_pos, orig_mref->ref_len);
+		qq_deactivate(&brick->q_phase[1]);
 		goto done;
 	}
 	if (!orig_mref_a->is_hashed) {
 		MARS_IO("AHA not hashed, pos = %lld len = %d\n", orig_mref->ref_pos, orig_mref->ref_len);
+		qq_deactivate(&brick->q_phase[1]);
 		goto done;
 	}
 
@@ -1845,12 +1863,22 @@ bool phase1_startio(struct trans_logger_mref_aspect *orig_mref_a)
 		qq_inc_flying(&brick->q_phase[1]);
 		fire_writeback(&wb->w_sub_read_list, false);
 	} else { // shortcut
-#ifndef SHORTCUT_1_to_3
-		qq_wb_insert(&brick->q_phase[3], wb);
-		wake_up_interruptible_all(&brick->worker_event);
-#else
-		return phase3_startio(wb);
+#ifdef SHORTCUT_1_to_3
+		bool res;
+
+		/* speculate that next phase can be immediately started */
+		qq_activate(&brick->q_phase[3]);
+		res = phase3_startio(wb);
+		if (likely(res)) {
+			qq_deactivate(&brick->q_phase[1]);
+			goto done;
+		}
+		/* speculation was wrong: no shortcutting */
+		qq_deactivate(&brick->q_phase[3]);
 #endif
+		qq_wb_insert(&brick->q_phase[3], wb);
+		qq_deactivate(&brick->q_phase[1]);
+		wake_up_interruptible_all(&brick->worker_event);
 	}
 
  done:
@@ -1906,6 +1934,7 @@ void phase2_endio(void *private, int error)
 		banning_reset(&brick->q_phase[2].q_banning);
 		_phase2_endio(wb);
 	}
+	qq_deactivate(&brick->q_phase[2]);
 	return;
 
 err:
@@ -2035,6 +2064,8 @@ void phase3_endio(struct generic_callback *cb)
 
 	banning_reset(&brick->q_phase[3].q_banning);
 
+	qq_deactivate(&brick->q_phase[3]);
+
 	wake_up_interruptible_all(&brick->worker_event);
 
 	return;