add simple rtt estimator

context.go

@@ -91,6 +91,9 @@ type Context[H Hash] struct {
 	lastBlockTime      time.Time // Wall clock time of when the last block was first seen (used for timer adjustments).
 	lastBlockIndex     uint32
 	lastBlockView      byte
+
+	prepareSentTime time.Time
+	rttEstimates    rtt
 }
 
 // N returns total number of validators.

dbft.go

@@ -153,6 +153,7 @@ func (d *DBFT[H]) initializeConsensus(view byte, ts uint64) {
 		var ts = d.Timer.Now()
 		var diff = ts.Sub(d.lastBlockTime)
 		timeout -= diff
+		timeout -= d.rttEstimates.avg
 		timeout = max(0, timeout)
 	}
 	d.changeTimer(timeout)
@@ -446,6 +447,10 @@ func (d *DBFT[H]) onPrepareResponse(msg ConsensusPayload[H]) {
 		return
 	}
 
+	if d.IsPrimary() {
+		d.rttEstimates.addTime(time.Since(d.prepareSentTime))
+	}
+
 	// ignore PrepareResponse if in process of changing view
 	m := d.PreparationPayloads[msg.ValidatorIndex()]
 	if m != nil || d.ViewChanging() && !d.MoreThanFNodesCommittedOrLost() {

rtt.go

@@ -0,0 +1,22 @@
+package dbft
+
+import (
+	"time"
+)
+
+const rttLength = 7 * 10
+
+type rtt struct {
+	times [rttLength]time.Duration
+	idx   int
+	avg   time.Duration
+}
+
+func (r *rtt) addTime(new time.Duration) {
+	var old = r.times[r.idx]
+
+	r.avg = r.avg + (new-old)/time.Duration(len(r.times))
+	r.avg = max(0, r.avg) // Can't be less than zero.
+	r.times[r.idx] = new
+	r.idx = (r.idx + 1) % len(r.times)
+}

send.go

@@ -27,6 +27,8 @@ func (d *DBFT[H]) sendPrepareRequest() {
 	d.PreparationPayloads[d.MyIndex] = msg
 	d.broadcast(msg)
 
+	d.prepareSentTime = d.Timer.Now()
+
 	delay := d.SecondsPerBlock << (d.ViewNumber + 1)
 	if d.ViewNumber == 0 {
 		delay -= d.SecondsPerBlock