dynamic-lambda: continue tracking the best proposal even after freezing

agreement/actions.go

@@ -66,6 +66,7 @@ type action interface {
 	do(context.Context, *Service)
 
 	String() string
+	ComparableStr() string
 }
 
 type nonpersistent struct{}
@@ -88,6 +89,8 @@ func (a noopAction) String() string {
 	return a.t().String()
 }
 
+func (a noopAction) ComparableStr() string { return a.String() }
+
 type networkAction struct {
 	nonpersistent
 
@@ -120,6 +123,13 @@ func (a networkAction) String() string {
 	return fmt.Sprintf("%s: %2v", a.t().String(), a.Tag)
 }
 
+func (a networkAction) ComparableStr() string {
+	if a.Tag == protocol.AgreementVoteTag {
+		return fmt.Sprintf("%s: %2v: %3v-%2v-%2v", a.t().String(), a.Tag, a.UnauthenticatedVote.R.Round, a.UnauthenticatedVote.R.Period, a.UnauthenticatedVote.R.Step)
+	}
+	return a.String()
+}
+
 func (a networkAction) do(ctx context.Context, s *Service) {
 	if a.T == broadcastVotes {
 		tag := protocol.AgreementVoteTag
@@ -192,6 +202,18 @@ func (a cryptoAction) String() string {
 	return a.t().String()
 }
 
+func (a cryptoAction) ComparableStr() (s string) {
+	switch a.T {
+	case verifyVote:
+		s = fmt.Sprintf("%s: %3v-%2v TaskIndex %d", a.t().String(), a.Round, a.Period, a.TaskIndex)
+	case verifyPayload:
+		s = fmt.Sprintf("%s: %3v-%2v Pinned %v", a.t().String(), a.Round, a.Period, a.Pinned)
+	case verifyBundle:
+		s = fmt.Sprintf("%s: %3v-%2v-%2v", a.t().String(), a.Round, a.Period, a.Step)
+	}
+	return
+}
+
 func (a cryptoAction) do(ctx context.Context, s *Service) {
 	switch a.T {
 	case verifyVote:
@@ -225,6 +247,8 @@ func (a ensureAction) String() string {
 	return fmt.Sprintf("%s: %.5s: %v, %v, %.5s", a.t().String(), a.Payload.Digest().String(), a.Certificate.Round, a.Certificate.Period, a.Certificate.Proposal.BlockDigest.String())
 }
 
+func (a ensureAction) ComparableStr() string { return a.String() }
+
 func (a ensureAction) do(ctx context.Context, s *Service) {
 	logEvent := logspec.AgreementEvent{
 		Hash:   a.Certificate.Proposal.BlockDigest.String(),
@@ -288,6 +312,8 @@ func (a stageDigestAction) String() string {
 	return fmt.Sprintf("%s: %.5s. %v. %v", a.t().String(), a.Certificate.Proposal.BlockDigest.String(), a.Certificate.Round, a.Certificate.Period)
 }
 
+func (a stageDigestAction) ComparableStr() string { return a.String() }
+
 func (a stageDigestAction) do(ctx context.Context, service *Service) {
 	logEvent := logspec.AgreementEvent{
 		Hash:   a.Certificate.Proposal.BlockDigest.String(),
@@ -314,8 +340,25 @@ func (a rezeroAction) String() string {
 	return a.t().String()
 }
 
+func (a rezeroAction) ComparableStr() string {
+	return fmt.Sprintf("%s: %d", a.t().String(), a.Round)
+}
+
 func (a rezeroAction) do(ctx context.Context, s *Service) {
 	s.Clock = s.Clock.Zero()
+	// Preserve the zero time of the new round a.Round (for
+	// period 0) for future use if a late proposal-vote arrives,
+	// for late credential tracking.
+	if _, ok := s.historicalClocks[a.Round]; !ok {
+		s.historicalClocks[a.Round] = s.Clock
+	}
+
+	// Garbage collect clocks that are too old
+	for rnd := range s.historicalClocks {
+		if a.Round > rnd+credentialRoundLag {
+			delete(s.historicalClocks, rnd)
+		}
+	}
 }
 
 type pseudonodeAction struct {
@@ -336,6 +379,8 @@ func (a pseudonodeAction) String() string {
 	return fmt.Sprintf("%v %3v-%2v-%2v: %.5v", a.t().String(), a.Round, a.Period, a.Step, a.Proposal.BlockDigest.String())
 }
 
+func (a pseudonodeAction) ComparableStr() string { return a.String() }
+
 func (a pseudonodeAction) persistent() bool {
 	return a.T == attest
 }
@@ -528,3 +573,5 @@ func (c checkpointAction) do(ctx context.Context, s *Service) {
 func (c checkpointAction) String() string {
 	return c.t().String()
 }
+
+func (c checkpointAction) ComparableStr() string { return c.String() }

agreement/demux.go

@@ -199,13 +199,13 @@ func (d *demux) next(s *Service, deadline Deadline, fastDeadline Deadline, curre
 
 		switch e.t() {
 		case payloadVerified:
-			e = e.(messageEvent).AttachValidatedAt(s.Clock.Since(), currentRound)
+			e = e.(messageEvent).AttachValidatedAt(clockForRound(currentRound, s.Clock, s.historicalClocks))
 		case payloadPresent, votePresent:
-			e = e.(messageEvent).AttachReceivedAt(s.Clock.Since(), currentRound)
+			e = e.(messageEvent).AttachReceivedAt(clockForRound(currentRound, s.Clock, s.historicalClocks))
 		case voteVerified:
 			// if this is a proposal vote (step 0), record the validatedAt time on the vote
 			if e.(messageEvent).Input.Vote.R.Step == 0 {
-				e = e.(messageEvent).AttachValidatedAt(s.Clock.Since(), currentRound)
+				e = e.(messageEvent).AttachValidatedAt(clockForRound(currentRound, s.Clock, s.historicalClocks))
 			}
 		}
 	}()

agreement/events.go

@@ -296,7 +296,7 @@ func (e messageEvent) String() string {
 }
 
 func (e messageEvent) ComparableStr() string {
-	return e.T.String()
+	return fmt.Sprintf("{T:%s %d Err:%v}", e.t().String(), e.ConsensusRound(), e.Err)
 }
 
 func (e messageEvent) ConsensusRound() round {
@@ -424,9 +424,14 @@ type readLowestEvent struct {
 
 	// Vote holds the lowest-credential vote.
 	Vote vote
+	// LowestIncludingLate holds the lowest-credential vote that was received, including
+	// after Vote has been frozen.
+	LowestIncludingLate vote
 
-	// Filled indicates whether the Vote field is filled
-	Filled bool
+	// Filled and HasLowestIncludingLate indicates whether the Vote or LowestIncludingLate
+	// fields are filled, respectively.
+	Filled                 bool
+	HasLowestIncludingLate bool
 }
 
 func (e readLowestEvent) t() eventType {
@@ -591,10 +596,36 @@ func (e payloadProcessedEvent) ComparableStr() string {
 	return fmt.Sprintf("%v: %.5v", e.t().String(), e.Proposal.BlockDigest.String())
 }
 
+// LateCredentialTrackingEffect indicates the impact of a vote that was filtered (due to age)
+// on the credential tracking system (in credentialArrivalHistory), for the purpose of tracking
+// the time it took the best credential to arrive, even if it was late.
+type LateCredentialTrackingEffect uint8
+
+const (
+	// NoLateCredentialTrackingImpact indicates the filtered event would have no impact on
+	// the credential tracking mechanism.
+	NoLateCredentialTrackingImpact LateCredentialTrackingEffect = iota
+
+	// UnverifiedLateCredentialForTracking indicates the filtered event could impact
+	// the credential tracking mechanism and more processing (validation) may be required.
+	// It may be set by proposalManager when handling votePresent events.
+	UnverifiedLateCredentialForTracking
+
+	// VerifiedBetterLateCredentialForTracking indicates that the filtered event provides a new best
+	// credential for its round.
+	// It may be set by proposalManager when handling voteVerified events.
+	VerifiedBetterLateCredentialForTracking
+)
+
 type filteredEvent struct {
 	// {proposal,vote,bundle}{Filtered,Malformed}
 	T eventType
 
+	// LateCredentialTrackingNote indicates the impact of the filtered event on the
+	// credential tracking machinery used for dynamically setting the filter
+	// timeout.
+	LateCredentialTrackingNote LateCredentialTrackingEffect
+
 	// Err is the reason cryptographic verification failed and is set for
 	// events {proposal,vote,bundle}Malformed.
 	Err *serializableError
@@ -975,50 +1006,60 @@ func (e checkpointEvent) AttachConsensusVersion(v ConsensusVersionView) external
 	return e
 }
 
+// This timestamp is assigned to messages that arrive for round R+1 while the current player
+// is still waiting for quorum on R.
+const pipelinedMessageTimestamp = time.Nanosecond
+
+//msgp:ignore constantRoundStartTimer
+type constantRoundStartTimer time.Duration
+
+func (c constantRoundStartTimer) Since() time.Duration { return time.Duration(c) }
+
+// clockForRound retrieves the roundStartTimer used for AttachValidatedAt and AttachReceivedAt.
+func clockForRound(currentRound round, currentClock roundStartTimer, historicalClocks map[round]roundStartTimer) func(round) roundStartTimer {
+	return func(eventRound round) roundStartTimer {
+		if eventRound > currentRound {
+			return constantRoundStartTimer(pipelinedMessageTimestamp)
+		}
+		if eventRound == currentRound {
+			return currentClock
+		}
+		if clock, ok := historicalClocks[eventRound]; ok {
+			return clock
+		}
+		return constantRoundStartTimer(0)
+	}
+}
+
 // AttachValidatedAt looks for a validated proposal or vote inside a
 // payloadVerified or voteVerified messageEvent, and attaches the given time to
 // the proposal's validatedAt field.
-func (e messageEvent) AttachValidatedAt(d time.Duration, currentRound round) messageEvent {
+func (e messageEvent) AttachValidatedAt(getClock func(eventRound round) roundStartTimer) messageEvent {
 	switch e.T {
 	case payloadVerified:
-		if e.Input.Proposal.Round() > currentRound {
-			e.Input.Proposal.validatedAt = 1
-		} else {
-			e.Input.Proposal.validatedAt = d
-		}
+		e.Input.Proposal.validatedAt = getClock(e.Input.Proposal.Round()).Since()
 	case voteVerified:
-		if e.Input.Vote.R.Round > currentRound {
-			e.Input.Vote.validatedAt = 1
-		} else {
-			e.Input.Vote.validatedAt = d
-		}
+		e.Input.Vote.validatedAt = getClock(e.Input.Vote.R.Round).Since()
 	}
 	return e
 }
 
 // AttachReceivedAt looks for an unauthenticatedProposal inside a
 // payloadPresent or votePresent messageEvent, and attaches the given
 // time to the proposal's receivedAt field.
-func (e messageEvent) AttachReceivedAt(d time.Duration, currentRound round) messageEvent {
-	if e.T == payloadPresent {
-		if e.Input.UnauthenticatedProposal.Round() > currentRound {
-			e.Input.UnauthenticatedProposal.receivedAt = 1
-		} else {
-			e.Input.UnauthenticatedProposal.receivedAt = d
-		}
-	} else if e.T == votePresent {
+func (e messageEvent) AttachReceivedAt(getClock func(eventRound round) roundStartTimer) messageEvent {
+	switch e.T {
+	case payloadPresent:
+		e.Input.UnauthenticatedProposal.receivedAt = getClock(e.Input.UnauthenticatedProposal.Round()).Since()
+	case votePresent:
 		// Check for non-nil Tail, indicating this votePresent event
 		// contains a synthetic payloadPresent event that was attached
 		// to it by setupCompoundMessage.
 		if e.Tail != nil && e.Tail.T == payloadPresent {
 			// The tail event is payloadPresent, serialized together
 			// with the proposal vote as a single CompoundMessage
 			// using a protocol.ProposalPayloadTag network message.
-			if e.Tail.Input.UnauthenticatedProposal.Round() > currentRound {
-				e.Tail.Input.UnauthenticatedProposal.receivedAt = 1
-			} else {
-				e.Tail.Input.UnauthenticatedProposal.receivedAt = d
-			}
+			e.Tail.Input.UnauthenticatedProposal.receivedAt = getClock(e.Tail.Input.UnauthenticatedProposal.Round()).Since()
 		}
 	}
 	return e

agreement/persistence.go

@@ -55,6 +55,21 @@ func persistent(as []action) bool {
 // encode serializes the current state into a byte array.
 func encode(t timers.Clock[TimeoutType], rr rootRouter, p player, a []action, reflect bool) (raw []byte) {
 	var s diskState
+
+	// Don't persist state for old rounds
+	// rootRouter.update() may preserve roundRouters from credentialRoundLag rounds ago
+	children := make(map[round]*roundRouter)
+	for rnd, rndRouter := range rr.Children {
+		if rnd >= p.Round {
+			children[rnd] = rndRouter
+		}
+	}
+	if len(children) == 0 {
+		rr.Children = nil
+	} else {
+		rr.Children = children
+	}
+
 	if reflect {
 		s.Router = protocol.EncodeReflect(rr)
 		s.Player = protocol.EncodeReflect(p)