From a2ce52efbf3391cb7eed3b26906eb0c1eca65280 Mon Sep 17 00:00:00 2001
From: Andrew Roldugin <andrew.roldugin@gmail.com>
Date: Tue, 21 Aug 2018 20:15:44 +0300
Subject: [PATCH] --ethash.difficulty

---
 cmd/geth/main.go              | 1 +
 cmd/geth/usage.go             | 1 +
 cmd/utils/flags.go            | 5 +++++
 consensus/ethash/consensus.go | 2 +-
 consensus/ethash/ethash.go    | 3 ++-
 eth/backend.go                | 1 +
 eth/config.go                 | 1 +
 7 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index d6aa9173e7..a298683fa8 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -72,6 +72,7 @@ var (
 		utils.EthashDatasetDirFlag,
 		utils.EthashDatasetsInMemoryFlag,
 		utils.EthashDatasetsOnDiskFlag,
+		utils.EthashDifficultyFlag,
 		utils.TxPoolNoLocalsFlag,
 		utils.TxPoolJournalFlag,
 		utils.TxPoolRejournalFlag,
diff --git a/cmd/geth/usage.go b/cmd/geth/usage.go
index d8b8e9804d..210cb5bba6 100644
--- a/cmd/geth/usage.go
+++ b/cmd/geth/usage.go
@@ -99,6 +99,7 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.EthashDatasetDirFlag,
 			utils.EthashDatasetsInMemoryFlag,
 			utils.EthashDatasetsOnDiskFlag,
+			utils.EthashDifficultyFlag,
 		},
 	},
 	//{
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 9eb725155e..da292bb953 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -241,6 +241,11 @@ var (
 		Usage: "Number of recent ethash mining DAGs to keep on disk (1+GB each)",
 		Value: ess.DefaultConfig.Ethash.DatasetsOnDisk,
 	}
+	EthashDifficultyFlag = BigFlag{
+		Name:  "ethash.difficulty",
+		Usage: "Difficulty of ethash",
+		Value: ess.DefaultConfig.Ethash.Difficulty,
+	}
 	// Transaction pool settings
 	TxPoolNoLocalsFlag = cli.BoolFlag{
 		Name:  "txpool.nolocals",
diff --git a/consensus/ethash/consensus.go b/consensus/ethash/consensus.go
index 4c541ce4e3..7250000584 100644
--- a/consensus/ethash/consensus.go
+++ b/consensus/ethash/consensus.go
@@ -288,7 +288,7 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
 // the difficulty that a new block should have when created at time
 // given the parent block's time and difficulty.
 func (ethash *Ethash) CalcDifficulty(chain consensus.ChainReader, time uint64, parent *types.Header) *big.Int {
-	return CalcDifficulty(chain.Config(), time, parent)
+	return ethash.config.Difficulty
 }
 
 // CalcDifficulty is the difficulty adjustment algorithm. It returns
diff --git a/consensus/ethash/ethash.go b/consensus/ethash/ethash.go
index 440835aaf1..f91ad00812 100644
--- a/consensus/ethash/ethash.go
+++ b/consensus/ethash/ethash.go
@@ -47,7 +47,7 @@ var (
 	maxUint256 = new(big.Int).Exp(big.NewInt(2), big.NewInt(256), big.NewInt(0))
 
 	// sharedEthash is a full instance that can be shared between multiple users.
-	sharedEthash = New(Config{"", 3, 0, "", 1, 0, ModeNormal})
+	sharedEthash = New(Config{"", 3, 0, "", 1, 0, ModeNormal, big.NewInt(1)})
 
 	// algorithmRevision is the data structure version used for file naming.
 	algorithmRevision = 23
@@ -387,6 +387,7 @@ type Config struct {
 	DatasetsInMem  int
 	DatasetsOnDisk int
 	PowMode        Mode
+	Difficulty     *big.Int
 }
 
 // Ethash is a consensus engine based on proof-of-work implementing the ethash
diff --git a/eth/backend.go b/eth/backend.go
index a134850339..d6d3ff4233 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -117,6 +117,7 @@ func New(ctx *node.ServiceContext, config *Config) (*Essentia, error) {
 		return nil, genesisErr
 	}
 	log.Info("Initialised chain configuration", "config", chainConfig)
+	log.Info("Ethash", "difficulty", config.Ethash.Difficulty)
 
 	ess := &Essentia{
 		config:         config,
diff --git a/eth/config.go b/eth/config.go
index c95e194b6e..315dc041c1 100644
--- a/eth/config.go
+++ b/eth/config.go
@@ -42,6 +42,7 @@ var DefaultConfig = Config{
 		CachesOnDisk:   3,
 		DatasetsInMem:  1,
 		DatasetsOnDisk: 2,
+		Difficulty:     big.NewInt(1),
 	},
 	NetworkId:     1,
 	LightPeers:    100,