refactor slot tickers with intervals (#12440)

* refactor slot tickers with intervals

* GoDoc

---------

Co-authored-by: Radosław Kapka <rkapka@wp.pl>

beacon-chain/blockchain/receive_attestation.go

@@ -92,22 +92,24 @@ func (s *Service) spawnProcessAttestationsRoutine() {
 			return
 		}
 
-		st := slots.NewSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
+		reorgInterval := time.Second*time.Duration(params.BeaconConfig().SecondsPerSlot) - reorgLateBlockCountAttestations
-		pat := slots.NewSlotTickerWithOffset(s.genesisTime, -reorgLateBlockCountAttestations, params.BeaconConfig().SecondsPerSlot)
+		ticker := slots.NewSlotTickerWithIntervals(s.genesisTime, []time.Duration{0, reorgInterval})
 		for {
 			select {
 			case <-s.ctx.Done():
 				return
-			case <-pat.C():
+			case slotInterval := <-ticker.C():
-				s.UpdateHead(s.ctx, s.CurrentSlot()+1)
+				if slotInterval.Interval > 0 {
-			case <-st.C():
+					s.UpdateHead(s.ctx, slotInterval.Slot+1)
-				s.cfg.ForkChoiceStore.Lock()
+				} else {
-				if err := s.cfg.ForkChoiceStore.NewSlot(s.ctx, s.CurrentSlot()); err != nil {
+					s.cfg.ForkChoiceStore.Lock()
-					log.WithError(err).Error("could not process new slot")
+					if err := s.cfg.ForkChoiceStore.NewSlot(s.ctx, slotInterval.Slot); err != nil {
-				}
+						log.WithError(err).Error("could not process new slot")
-				s.cfg.ForkChoiceStore.Unlock()
+					}
+					s.cfg.ForkChoiceStore.Unlock()
 
-				s.UpdateHead(s.ctx, s.CurrentSlot())
+					s.UpdateHead(s.ctx, slotInterval.Slot)
+				}
 			}
 		}
 	}()

beacon-chain/operations/attestations/prepare_forkchoice.go

@@ -34,14 +34,17 @@ func (s *Service) prepareForkChoiceAtts() {
 	ticker := slots.NewSlotTickerWithIntervals(time.Unix(int64(s.genesisTime), 0), intervals[:])
 	for {
 		select {
-		case <-ticker.C():
+		case slotInterval := <-ticker.C():
 			t := time.Now()
 			if err := s.batchForkChoiceAtts(s.ctx); err != nil {
 				log.WithError(err).Error("Could not prepare attestations for fork choice")
 			}
-			if slots.TimeIntoSlot(s.genesisTime) < intervals[1] {
+			switch slotInterval.Interval {
-				batchForkChoiceAttsT1.Observe(float64(time.Since(t).Milliseconds()))
+			case 0:
-			} else if slots.TimeIntoSlot(s.genesisTime) < intervals[2] {
+				duration := time.Since(t)
+				log.WithField("Duration", duration).Debug("aggregated unaggregated attestations")
+				batchForkChoiceAttsT1.Observe(float64(duration.Milliseconds()))
+			case 1:
 				batchForkChoiceAttsT2.Observe(float64(time.Since(t).Milliseconds()))
 			}
 		case <-s.ctx.Done():

time/slots/slotticker.go

@@ -16,6 +16,20 @@ type Ticker interface {
 	Done()
 }
 
+// SlotInterval is a wrapper that contains a slot and the interval index that
+// triggered the ticker
+type SlotInterval struct {
+	Slot     primitives.Slot
+	Interval int
+}
+
+// The IntervalTicker is similar to the Ticker interface but
+// exposes also the interval along with the slot number
+type IntervalTicker interface {
+	C() <-chan SlotInterval
+	Done()
+}
+
 // SlotTicker is a special ticker for the beacon chain block.
 // The channel emits over the slot interval, and ensures that
 // the ticks are in line with the genesis time. This means that
@@ -27,12 +41,25 @@ type SlotTicker struct {
 	done chan struct{}
 }
 
+// SlotIntervalTicker is similar to a slot ticker but it returns also
+// the index of the interval that triggered the event
+type SlotIntervalTicker struct {
+	c    chan SlotInterval
+	done chan struct{}
+}
+
 // C returns the ticker channel. Call Cancel afterwards to ensure
 // that the goroutine exits cleanly.
 func (s *SlotTicker) C() <-chan primitives.Slot {
 	return s.c
 }
 
+// C returns the ticker channel. Call Cancel afterwards to ensure
+// that the goroutine exits cleanly.
+func (s *SlotIntervalTicker) C() <-chan SlotInterval {
+	return s.c
+}
+
 // Done should be called to clean up the ticker.
 func (s *SlotTicker) Done() {
 	go func() {
@@ -40,6 +67,13 @@ func (s *SlotTicker) Done() {
 	}()
 }
 
+// Done should be called to clean up the ticker.
+func (s *SlotIntervalTicker) Done() {
+	go func() {
+		s.done <- struct{}{}
+	}()
+}
+
 // NewSlotTicker starts and returns a new SlotTicker instance.
 func NewSlotTicker(genesisTime time.Time, secondsPerSlot uint64) *SlotTicker {
 	if genesisTime.IsZero() {
@@ -109,7 +143,7 @@ func (s *SlotTicker) start(
 // startWithIntervals starts a ticker that emits a tick every slot at the
 // prescribed intervals. The caller is responsible to make these intervals increasing and
 // less than secondsPerSlot
-func (s *SlotTicker) startWithIntervals(
+func (s *SlotIntervalTicker) startWithIntervals(
 	genesisTime time.Time,
 	until func(time.Time) time.Duration,
 	after func(time.Duration) <-chan time.Time,
@@ -124,7 +158,7 @@ func (s *SlotTicker) startWithIntervals(
 			waitTime := until(nextTickTime)
 			select {
 			case <-after(waitTime):
-				s.c <- slot
+				s.c <- SlotInterval{Slot: slot, Interval: interval}
 				interval++
 				if interval == len(intervals) {
 					interval = 0
@@ -142,7 +176,7 @@ func (s *SlotTicker) startWithIntervals(
 // several offsets of time from genesis,
 // Caller is responsible to input the intervals in increasing order and none bigger or equal than
 // SecondsPerSlot
-func NewSlotTickerWithIntervals(genesisTime time.Time, intervals []time.Duration) *SlotTicker {
+func NewSlotTickerWithIntervals(genesisTime time.Time, intervals []time.Duration) *SlotIntervalTicker {
 	if genesisTime.Unix() == 0 {
 		panic("zero genesis time")
 	}
@@ -160,8 +194,8 @@ func NewSlotTickerWithIntervals(genesisTime time.Time, intervals []time.Duration
 		}
 		lastOffset = offset
 	}
-	ticker := &SlotTicker{
+	ticker := &SlotIntervalTicker{
-		c:    make(chan primitives.Slot),
+		c:    make(chan SlotInterval),
 		done: make(chan struct{}),
 	}
 	ticker.startWithIntervals(genesisTime, prysmTime.Until, time.After, intervals)