Implement command line argument to set the amount of agents created by the miner

Defaults to the amount of cores available on the CPU

cmd/mist/flags.go

@@ -63,6 +63,7 @@ var (
 	DebugFile       string
 	LogLevel        int
 	VmType          int
+	MinerThreads    int
 )
 
 // flags specific to gui client
@@ -137,6 +138,8 @@ func Init() {
 	flag.StringVar(&BootNodes, "bootnodes", "", "space-separated node URLs for discovery bootstrap")
 	flag.IntVar(&MaxPeer, "maxpeer", 30, "maximum desired peers")
 
+	flag.IntVar(&MinerThreads, "minerthreads", runtime.NumCPU(), "number of miner threads")
+
 	flag.Parse()
 
 	var err error

cmd/mist/main.go

@@ -65,6 +65,7 @@ func run() error {
 		NodeKey:      NodeKey,
 		KeyRing:      KeyRing,
 		Dial:         true,
+		MinerThreads: MinerThreads,
 	})
 	if err != nil {
 		mainlogger.Fatalln(err)

cmd/utils/cmd.go

@@ -225,7 +225,7 @@ func StartMining(ethereum *eth.Ethereum) bool {
 		go func() {
 			clilogger.Infoln("Start mining")
 			if gminer == nil {
-				gminer = miner.New(addr, ethereum)
+				gminer = miner.New(addr, ethereum, 4)
 			}
 			gminer.Start()
 		}()

eth/backend.go

@@ -53,6 +53,8 @@ type Config struct {
 	Shh  bool
 	Dial bool
 
+	MinerThreads int
+
 	KeyManager *crypto.KeyManager
 }
 
@@ -153,7 +155,7 @@ func New(config *Config) (*Ethereum, error) {
 	eth.blockProcessor = core.NewBlockProcessor(db, eth.txPool, eth.chainManager, eth.EventMux())
 	eth.chainManager.SetProcessor(eth.blockProcessor)
 	eth.whisper = whisper.New()
-	eth.miner = miner.New(keyManager.Address(), eth)
+	eth.miner = miner.New(keyManager.Address(), eth, config.MinerThreads)
 
 	hasBlock := eth.chainManager.HasBlock
 	insertChain := eth.chainManager.InsertChain

miner/miner.go

@@ -20,13 +20,13 @@ type Miner struct {
 	mining   bool
 }
 
-func New(coinbase []byte, eth core.Backend) *Miner {
+func New(coinbase []byte, eth core.Backend, minerThreads int) *Miner {
 	miner := &Miner{
 		Coinbase: coinbase,
 		worker:   newWorker(coinbase, eth),
 	}
 
-	for i := 0; i < 4; i++ {
+	for i := 0; i < minerThreads; i++ {
 		miner.worker.register(NewCpuMiner(i, ezp.New()))
 	}