cmd, eth, miner: experimental zero-diff miner for dev/hack networks

cmd/geth/main.go

@@ -106,6 +106,9 @@ func init() {
 		utils.MiningEnabledFlag,
 		utils.AutoDAGFlag,
 		utils.TargetGasLimitFlag,
+		utils.StrategyZerodiffEnabledFlag,
+		utils.StrategyZerodiffInstantTxsFlag,
+		utils.StrategyZerodiffMinEtherFlag,
 		utils.NATFlag,
 		utils.NatspecEnabledFlag,
 		utils.NoDiscoverFlag,

cmd/geth/usage.go

@@ -139,6 +139,14 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.ExtraDataFlag,
 		},
 	},
+	{
+		Name: "MINER STRATEGY",
+		Flags: []cli.Flag{
+			utils.StrategyZerodiffEnabledFlag,
+			utils.StrategyZerodiffInstantTxsFlag,
+			utils.StrategyZerodiffMinEtherFlag,
+		},
+	},
 	{
 		Name: "GAS PRICE ORACLE",
 		Flags: []cli.Flag{

cmd/utils/flags.go

@@ -43,6 +43,7 @@ import (
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/miner"
 	"github.com/ethereum/go-ethereum/node"
 	"github.com/ethereum/go-ethereum/p2p/discover"
 	"github.com/ethereum/go-ethereum/p2p/discv5"
@@ -210,6 +211,19 @@ var (
 		Name:  "extradata",
 		Usage: "Block extra data set by the miner (default = client version)",
 	}
+	StrategyZerodiffEnabledFlag = cli.BoolFlag{
+		Name:  "miner.zerodiff",
+		Usage: "Enables the base zero-diff miner strategy (private networks)",
+	}
+	StrategyZerodiffInstantTxsFlag = cli.BoolFlag{
+		Name:  "miner.zerodiff.instanttxs",
+		Usage: "Ignores zero-diff delays if block contains transactions (private networks)",
+	}
+	StrategyZerodiffMinEtherFlag = cli.IntFlag{
+		Name:  "miner.zerodiff.minether",
+		Usage: "Ignores zero-diff delays if miner balance is below threshold (private networks)",
+		Value: 0,
+	}
 	// Account settings
 	UnlockedAccountFlag = cli.StringFlag{
 		Name:  "unlock",
@@ -636,6 +650,24 @@ func MakeMinerExtra(extra []byte, ctx *cli.Context) []byte {
 	return extra
 }
 
+// MakeMinerStrategies assembles any miner strategies from the set command line
+// flags.
+func MakeMinerStrategies(ctx *cli.Context) []*miner.Strategy {
+	var strategies []*miner.Strategy
+
+	// If zero-diff mining is requested, assemble it
+	var (
+		zerodiffBaseline   = ctx.GlobalBool(StrategyZerodiffEnabledFlag.Name)
+		zerodiffInstanttxs = ctx.GlobalBool(StrategyZerodiffInstantTxsFlag.Name)
+		zerodiffThreshold  = ctx.GlobalInt(StrategyZerodiffMinEtherFlag.Name)
+	)
+	if zerodiffBaseline || zerodiffInstanttxs || zerodiffThreshold > 0 {
+		threshold := new(big.Int).Mul(big.NewInt(int64(zerodiffThreshold)), common.Ether)
+		strategies = append(strategies, miner.NewZeroDiffStrategy(zerodiffInstanttxs, threshold))
+	}
+	return strategies
+}
+
 // MakePasswordList reads password lines from the file specified by --password.
 func MakePasswordList(ctx *cli.Context) []string {
 	path := ctx.GlobalString(PasswordFileFlag.Name)
@@ -737,6 +769,7 @@ func RegisterEthService(ctx *cli.Context, stack *node.Node, extra []byte) {
 		DatabaseHandles:         MakeDatabaseHandles(),
 		NetworkId:               ctx.GlobalInt(NetworkIdFlag.Name),
 		MinerThreads:            ctx.GlobalInt(MinerThreadsFlag.Name),
+		MinerStrategies:         MakeMinerStrategies(ctx),
 		ExtraData:               MakeMinerExtra(extra, ctx),
 		NatSpec:                 ctx.GlobalBool(NatspecEnabledFlag.Name),
 		DocRoot:                 ctx.GlobalString(DocRootFlag.Name),

eth/backend.go

@@ -86,6 +86,7 @@ type Config struct {
 	Etherbase       common.Address
 	GasPrice        *big.Int
 	MinerThreads    int
+	MinerStrategies []*miner.Strategy
 	SolcPath        string
 
 	GpoMinGasPrice          *big.Int
@@ -242,7 +243,7 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 	if eth.protocolManager, err = NewProtocolManager(eth.chainConfig, config.FastSync, config.NetworkId, maxPeers, eth.eventMux, eth.txPool, eth.pow, eth.blockchain, chainDb); err != nil {
 		return nil, err
 	}
-	eth.miner = miner.New(eth, eth.chainConfig, eth.EventMux(), eth.pow)
+	eth.miner = miner.New(eth, eth.chainConfig, eth.EventMux(), eth.pow, config.MinerStrategies)
 	eth.miner.SetGasPrice(config.GasPrice)
 	eth.miner.SetExtra(config.ExtraData)
 

miner/miner.go

@@ -60,12 +60,12 @@ type Miner struct {
 	shouldStart int32 // should start indicates whether we should start after sync
 }
 
-func New(eth Backend, config *params.ChainConfig, mux *event.TypeMux, pow pow.PoW) *Miner {
+func New(eth Backend, config *params.ChainConfig, mux *event.TypeMux, pow pow.PoW, strategies []*Strategy) *Miner {
 	miner := &Miner{
 		eth:      eth,
 		mux:      mux,
 		pow:      pow,
-		worker:   newWorker(config, common.Address{}, eth, mux),
+		worker:   newWorker(config, common.Address{}, eth, mux, strategies),
 		canStart: 1,
 	}
 	go miner.update()

miner/strategy.go

@@ -0,0 +1,112 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package miner
+
+import (
+	"errors"
+	"math/big"
+	"math/rand"
+	"time"
+
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/event"
+)
+
+// Strategy is a collection of optional callback methods that miner strategies
+// may implement to influence the behavior of the miner.
+type Strategy struct {
+	Name string // Name of the strategy for logging purposes
+
+	// OnMinedBlock is invoked when a new block is mined by the miner.
+	OnMinedBlock func(emux *event.TypeMux, chain *core.BlockChain, pool *core.TxPool, block *types.Block) error
+}
+
+// NewZeroDiffStrategy creates a mining strategy that aims to push the difficulty
+// of the blocks down to zero. It tries to achive this by delaying found blocks
+// to always be above the configured block time limit, pushing the difficulty
+// down a bit after every block.
+//
+// The strategy has a few nice properties that is orthogonal both to multiple
+// zero-diff miners as well as other plain miners:
+//
+//  * The zero-diff miner may be ran with arbitrarilly many threads: if a block
+//    is found faster than the target block time, it will be delayed anyway, so
+//    the mining threads will go idle. If on the other hand the difficulty is
+//    pushed up by a rouge miner and abandoned, the multiple threads will allow
+//    pulling the difficulty down faster until it reaches sub-target times.
+//  * The zero-diff miner can play along nicely with non zero-diff miners, since
+//    it will either delay it's block to above-target times, or outright discard
+//    its own block if another is found, thereby ensuring it only ever reduces
+//    the difficulty, never increases.
+//  * The zero-diff miner can also play along nicely with other zero-diff miners
+//    by simulating block times at random between [target, 1.1*target], allowing
+//    multiple zero-diff miners to co-exist and share blocks, without racing each
+//    other for blocks and leading to a high uncle rate.
+//
+// Note, this strategy is only meaningful in trusted private networks where the
+// goal of mining is not to secure the network, rather to provide a stable but
+// resource-light testbed.
+func NewZeroDiffStrategy(instantTxs bool, minBalance *big.Int) *Strategy {
+	return &Strategy{
+		Name: "zero-diff",
+
+		OnMinedBlock: func(emux *event.TypeMux, chain *core.BlockChain, pool *core.TxPool, block *types.Block) error {
+			// A new block was mined, calculate the required delay
+			elapsed := time.Since(time.Unix(block.Time().Int64(), 0))
+			delay := float64(15*time.Second)*(1.0+rand.Float64()/10.0) - float64(elapsed)
+
+			// If the delay is negative, block times are way over the target already, release
+			if delay <= 0 {
+				return nil
+			}
+			// If instant transactions are enabled and the block contains something, release
+			if instantTxs && len(block.Transactions()) > 0 {
+				return nil
+			}
+			// If minimum balance requirements are set but not met, release
+			if minBalance != nil {
+				if state, _ := chain.State(); state.GetBalance(block.Coinbase()).Cmp(minBalance) < 0 {
+					return nil
+				}
+			}
+			// Otherwise monitor head and transaction events
+			head := emux.Subscribe(core.ChainHeadEvent{})
+			defer head.Unsubscribe()
+
+			txs := emux.Subscribe(core.TxPreEvent{})
+			defer txs.Unsubscribe()
+
+			// Double check for events that happened before subscriptions
+			if chain.CurrentHeader().Hash() != block.ParentHash() {
+				return errors.New("stale block") // Another block arrived already, drop this
+			}
+			if pend, _ := pool.Stats(); pend > 0 {
+				return nil // Transaction pending in the pool, release this and start processing them
+			}
+			// Wait for some event to occur that releases or bins the block
+			select {
+			case <-time.After(time.Duration(delay)):
+				return nil // Timeout for difficulty reduction reached, release
+			case <-head.Chan():
+				return errors.New("concurrent block") // Alternate block arrived, drop this
+			case <-txs.Chan():
+				return nil // Transaction arrived, include it as fast as possible
+			}
+		},
+	}
+}

miner/worker.go

@@ -117,7 +117,8 @@ type worker struct {
 	txQueueMu sync.Mutex
 	txQueue   map[common.Hash]*types.Transaction
 
-	unconfirmed *unconfirmedBlocks // set of locally mined blocks pending canonicalness confirmations
+	unconfirmed *unconfirmedBlocks // Set of locally mined blocks pending confirmation
+	strategies  []*Strategy        // Miner strategies currently ran by the miner
 
 	// atomic status counters
 	mining int32
@@ -126,7 +127,7 @@ type worker struct {
 	fullValidation bool
 }
 
-func newWorker(config *params.ChainConfig, coinbase common.Address, eth Backend, mux *event.TypeMux) *worker {
+func newWorker(config *params.ChainConfig, coinbase common.Address, eth Backend, mux *event.TypeMux, strategies []*Strategy) *worker {
 	worker := &worker{
 		config:         config,
 		eth:            eth,
@@ -141,6 +142,7 @@ func newWorker(config *params.ChainConfig, coinbase common.Address, eth Backend,
 		txQueue:        make(map[common.Hash]*types.Transaction),
 		agents:         make(map[Agent]struct{}),
 		unconfirmed:    newUnconfirmedBlocks(eth.BlockChain(), 5),
+		strategies:     strategies,
 		fullValidation: false,
 	}
 	worker.events = worker.mux.Subscribe(core.ChainHeadEvent{}, core.ChainSideEvent{}, core.TxPreEvent{})
@@ -278,6 +280,22 @@ func (self *worker) wait() {
 			block := result.Block
 			work := result.Work
 
+			// Run any miner strategies interested in block mine results and ensure none denies this block
+			denied := false
+			for _, strat := range self.strategies {
+				if strat.OnMinedBlock != nil {
+					glog.V(logger.Debug).Infof("Passing mined block #%d [%x…] to strategy %s", block.Number(), block.Hash().Bytes()[:4], strat.Name)
+					if err := strat.OnMinedBlock(self.mux, self.chain, self.eth.TxPool(), block); err != nil {
+						glog.V(logger.Debug).Infof("Mined block #%d [%x…] denied by strategy %s: %v", block.Number(), block.Hash().Bytes()[:4], strat.Name, err)
+						denied = true
+						break
+					}
+					glog.V(logger.Debug).Infof("Mined block #%d [%x…] accepted by strategy %s", block.Number(), block.Hash().Bytes()[:4], strat.Name)
+				}
+			}
+			if denied {
+				continue
+			}
 			if self.fullValidation {
 				if _, err := self.chain.InsertChain(types.Blocks{block}); err != nil {
 					glog.V(logger.Error).Infoln("mining err", err)