fix(payload-builder): include PoL tx in empty payload (#94) (#98)

* Update worker.go

* make updates

* nit

* add log for payload update count

* fix bug

* cleanup metric/logs

* 1s recommit + with more descriptive logs

---------


(cherry picked from commit 817107f)

Co-authored-by: Rez <rez@berachain.com>
Co-authored-by: Cal Bera <calbera@berachain.com>

Author: 3 people

miner/miner.go

@@ -55,11 +55,10 @@ var DefaultConfig = Config{
 	GasCeil:  36_000_000,    // Berachain: set to 36mil to match Prague default
 	GasPrice: big.NewInt(1), // Berachain: set to 1 wei to match reth's default
 
-	// The default recommit time is chosen as two seconds since
-	// consensus-layer usually will wait a half slot of time(6s)
-	// for payload generation. It should be enough for Geth to
-	// run 3 rounds.
-	Recommit: 2 * time.Second,
+	// Berachain: The default recommit time is chosen as 1s to allow for around
+	// 1-2 rounds of payload generation. On average with 2s stable block time,
+	// there is 1.5s gap between start and stop payload generation.
+	Recommit: 1 * time.Second,
 }
 
 // Miner is the main object which takes care of submitting new work to consensus

miner/payload_building.go

@@ -102,7 +102,7 @@ func newPayload(empty *types.Block, emptyRequests [][]byte, witness *stateless.W
 }
 
 // update updates the full-block with latest built version.
-func (payload *Payload) update(r *newPayloadResult, elapsed time.Duration) {
+func (payload *Payload) update(r *newPayloadResult, elapsed time.Duration, numPayloadUpdates int) {
 	payload.lock.Lock()
 	defer payload.lock.Unlock()
 
@@ -132,6 +132,7 @@ func (payload *Payload) update(r *newPayloadResult, elapsed time.Duration) {
 			"fees", feesInEther,
 			"root", r.block.Root(),
 			"elapsed", common.PrettyDuration(elapsed),
+			"count", numPayloadUpdates,
 		)
 	}
 	payload.cond.Broadcast() // fire signal for notifying full block
@@ -260,22 +261,24 @@ func (miner *Miner) buildPayload(args *BuildPayloadArgs, witness bool) (*Payload
 			noTxs:          false,
 		}
 
+		numPayloadUpdates := 0
 		for {
 			select {
 			case <-timer.C:
 				start := time.Now()
 				r := miner.generateWork(fullParams, witness)
 				if r.err == nil {
-					payload.update(r, time.Since(start))
+					numPayloadUpdates++
+					payload.update(r, time.Since(start), numPayloadUpdates)
 				} else {
 					log.Info("Error while generating work", "id", payload.id, "err", r.err)
 				}
 				timer.Reset(miner.config.Recommit)
 			case <-payload.stop:
-				log.Info("Stopping work on payload", "id", payload.id, "reason", "delivery")
+				log.Info("Stopping work on payload", "id", payload.id, "reason", "delivery", "full", payload.full != nil)
 				return
 			case <-endTimer.C:
-				log.Info("Stopping work on payload", "id", payload.id, "reason", "timeout")
+				log.Info("Stopping work on payload", "id", payload.id, "reason", "timeout", "full", payload.full != nil)
 				return
 			}
 		}

miner/worker.go

@@ -122,6 +122,13 @@ func (miner *Miner) generateWork(genParam *generateParams, witness bool) *newPay
 	// Also add size of withdrawals to work block size.
 	work.size += uint64(genParam.withdrawals.Size())
 
+	// Berachain: Post-Prague1 we commit the PoL tx even when building an empty block.
+	// This is a safety measure to ensure that if the payload is requested early, the
+	// returned payload satisfies the Prague1 requirements, i.e. include the PoL tx.
+	if err = miner.commitPoLTx(work); err != nil {
+		return &newPayloadResult{err: err}
+	}
+
 	if !genParam.noTxs {
 		interrupt := new(atomic.Int32)
 		timer := time.AfterFunc(miner.config.Recommit, func() {
@@ -483,16 +490,8 @@ func (miner *Miner) commitTransactions(env *environment, plainTxs, blobTxs *tran
 	return nil
 }
 
-// fillTransactions retrieves the pending transactions from the txpool and fills them
-// into the given sealing block. The transaction selection and ordering strategy can
-// be customized with the plugin in the future.
-func (miner *Miner) fillTransactions(interrupt *atomic.Int32, env *environment) error {
-	miner.confMu.RLock()
-	tip := miner.config.GasPrice
-	prio := miner.prio
-	miner.confMu.RUnlock()
-
-	// Berachain: Post-Prague1, add PoL tx to the block according to BRIP-0004.
+// Berachain: Post-Prague1, add PoL tx to the block according to BRIP-0004.
+func (miner *Miner) commitPoLTx(env *environment) error {
 	if env.gasPool == nil {
 		// NOTE: this check is moved here from the commitTransactions loop because we are
 		// "committing" a transaction outside of the loop.
@@ -519,6 +518,17 @@ func (miner *Miner) fillTransactions(interrupt *atomic.Int32, env *environment)
 			return err
 		}
 	}
+	return nil
+}
+
+// fillTransactions retrieves the pending transactions from the txpool and fills them
+// into the given sealing block. The transaction selection and ordering strategy can
+// be customized with the plugin in the future.
+func (miner *Miner) fillTransactions(interrupt *atomic.Int32, env *environment) error {
+	miner.confMu.RLock()
+	tip := miner.config.GasPrice
+	prio := miner.prio
+	miner.confMu.RUnlock()
 
 	// Retrieve the pending transactions pre-filtered by the 1559/4844 dynamic fees
 	filter := txpool.PendingFilter{