1 files changed, 58 insertions, 18 deletions

diff --git a/eth/backend.go b/eth/backend.go
index 648175acf..c530d3c7c 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -102,12 +102,18 @@ func (s *Ethereum) AddLesServer(ls LesServer) {
 // New creates a new Ethereum object (including the
 // initialisation of the common Ethereum object)
 func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
+	// Ensure configuration values are compatible and sane
 	if config.SyncMode == downloader.LightSync {
 		return nil, errors.New("can't run eth.Ethereum in light sync mode, use les.LightEthereum")
 	}
 	if !config.SyncMode.IsValid() {
 		return nil, fmt.Errorf("invalid sync mode %d", config.SyncMode)
 	}
+	if config.MinerGasPrice == nil || config.MinerGasPrice.Cmp(common.Big0) <= 0 {
+		log.Warn("Sanitizing invalid miner gas price", "provided", config.MinerGasPrice, "updated", DefaultConfig.MinerGasPrice)
+		config.MinerGasPrice = new(big.Int).Set(DefaultConfig.MinerGasPrice)
+	}
+	// Assemble the Ethereum object
 	chainDb, err := CreateDB(ctx, config, "chaindata")
 	if err != nil {
 		return nil, err
@@ -333,32 +339,66 @@ func (s *Ethereum) SetEtherbase(etherbase common.Address) {
 	s.miner.SetEtherbase(etherbase)
 }
 
-func (s *Ethereum) StartMining(local bool) error {
-	eb, err := s.Etherbase()
-	if err != nil {
-		log.Error("Cannot start mining without etherbase", "err", err)
-		return fmt.Errorf("etherbase missing: %v", err)
+// StartMining starts the miner with the given number of CPU threads. If mining
+// is already running, this method adjust the number of threads allowed to use
+// and updates the minimum price required by the transaction pool.
+func (s *Ethereum) StartMining(threads int) error {
+	// Update the thread count within the consensus engine
+	type threaded interface {
+		SetThreads(threads int)
 	}
-	if clique, ok := s.engine.(*clique.Clique); ok {
-		wallet, err := s.accountManager.Find(accounts.Account{Address: eb})
-		if wallet == nil || err != nil {
-			log.Error("Etherbase account unavailable locally", "err", err)
-			return fmt.Errorf("signer missing: %v", err)
+	if th, ok := s.engine.(threaded); ok {
+		log.Info("Updated mining threads", "threads", threads)
+		if threads == 0 {
+			threads = -1 // Disable the miner from within
 		}
-		clique.Authorize(eb, wallet.SignHash)
+		th.SetThreads(threads)
 	}
-	if local {
-		// If local (CPU) mining is started, we can disable the transaction rejection
-		// mechanism introduced to speed sync times. CPU mining on mainnet is ludicrous
-		// so none will ever hit this path, whereas marking sync done on CPU mining
-		// will ensure that private networks work in single miner mode too.
+	// If the miner was not running, initialize it
+	if !s.IsMining() {
+		// Propagate the initial price point to the transaction pool
+		s.lock.RLock()
+		price := s.gasPrice
+		s.lock.RUnlock()
+		s.txPool.SetGasPrice(price)
+
+		// Configure the local mining addess
+		eb, err := s.Etherbase()
+		if err != nil {
+			log.Error("Cannot start mining without etherbase", "err", err)
+			return fmt.Errorf("etherbase missing: %v", err)
+		}
+		if clique, ok := s.engine.(*clique.Clique); ok {
+			wallet, err := s.accountManager.Find(accounts.Account{Address: eb})
+			if wallet == nil || err != nil {
+				log.Error("Etherbase account unavailable locally", "err", err)
+				return fmt.Errorf("signer missing: %v", err)
+			}
+			clique.Authorize(eb, wallet.SignHash)
+		}
+		// If mining is started, we can disable the transaction rejection mechanism
+		// introduced to speed sync times.
 		atomic.StoreUint32(&s.protocolManager.acceptTxs, 1)
+
+		go s.miner.Start(eb)
 	}
-	go s.miner.Start(eb)
 	return nil
 }
 
-func (s *Ethereum) StopMining()         { s.miner.Stop() }
+// StopMining terminates the miner, both at the consensus engine level as well as
+// at the block creation level.
+func (s *Ethereum) StopMining() {
+	// Update the thread count within the consensus engine
+	type threaded interface {
+		SetThreads(threads int)
+	}
+	if th, ok := s.engine.(threaded); ok {
+		th.SetThreads(-1)
+	}
+	// Stop the block creating itself
+	s.miner.Stop()
+}
+
 func (s *Ethereum) IsMining() bool      { return s.miner.Mining() }
 func (s *Ethereum) Miner() *miner.Miner { return s.miner }