From 71d32f54f70917c53fd3a691cface3bc73ffa1b7 Mon Sep 17 00:00:00 2001
From: Jeffrey Wilcke <geffobscura@gmail.com>
Date: Tue, 4 Aug 2015 23:46:38 +0200
Subject: [PATCH] core, miner: added difficulty bomb
---
core/block_processor.go | 2 +-
core/chain_makers.go | 2 +-
core/chain_util.go | 20 ++++-
core/chain_util_test.go | 77 +++++++++++++++++++
miner/worker.go | 2 +-
tests/files/BasicTests/difficulty.json | 100 +++++++++++++++++++++++++
6 files changed, 196 insertions(+), 7 deletions(-)
create mode 100644 core/chain_util_test.go
create mode 100644 tests/files/BasicTests/difficulty.json
diff --git a/core/block_processor.go b/core/block_processor.go
index 6687cd000..5a2ad8377 100644
--- a/core/block_processor.go
+++ b/core/block_processor.go
@@ -386,7 +386,7 @@ func ValidateHeader(pow pow.PoW, block *types.Header, parent *types.Block, check
return BlockEqualTSErr
}
- expd := CalcDifficulty(block.Time, parent.Time(), parent.Difficulty())
+ expd := CalcDifficulty(block.Time, parent.Time(), parent.Number(), parent.Difficulty())
if expd.Cmp(block.Difficulty) != 0 {
return fmt.Errorf("Difficulty check failed for block %v, %v", block.Difficulty, expd)
}
diff --git a/core/chain_makers.go b/core/chain_makers.go
index 283653d9a..85a6175dc 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -171,7 +171,7 @@ func makeHeader(parent *types.Block, state *state.StateDB) *types.Header {
Root: state.Root(),
ParentHash: parent.Hash(),
Coinbase: parent.Coinbase(),
- Difficulty: CalcDifficulty(time, parent.Time(), parent.Difficulty()),
+ Difficulty: CalcDifficulty(time, parent.Time(), parent.Number(), parent.Difficulty()),
GasLimit: CalcGasLimit(parent),
GasUsed: new(big.Int),
Number: new(big.Int).Add(parent.Number(), common.Big1),
diff --git a/core/chain_util.go b/core/chain_util.go
index 104670195..34f6c8d0a 100644
--- a/core/chain_util.go
+++ b/core/chain_util.go
@@ -30,14 +30,15 @@ import (
)
var (
- blockHashPre = []byte("block-hash-")
- blockNumPre = []byte("block-num-")
+ blockHashPre = []byte("block-hash-")
+ blockNumPre = []byte("block-num-")
+ expDiffPeriod = big.NewInt(100000)
)
// CalcDifficulty is the difficulty adjustment algorithm. It returns
// the difficulty that a new block b should have when created at time
// given the parent block's time and difficulty.
-func CalcDifficulty(time, parentTime uint64, parentDiff *big.Int) *big.Int {
+func CalcDifficulty(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
diff := new(big.Int)
adjust := new(big.Int).Div(parentDiff, params.DifficultyBoundDivisor)
bigTime := new(big.Int)
@@ -52,8 +53,19 @@ func CalcDifficulty(time, parentTime uint64, parentDiff *big.Int) *big.Int {
diff.Sub(parentDiff, adjust)
}
if diff.Cmp(params.MinimumDifficulty) < 0 {
- return params.MinimumDifficulty
+ diff = params.MinimumDifficulty
}
+
+ periodCount := new(big.Int).Add(parentNumber, common.Big1)
+ periodCount.Div(periodCount, expDiffPeriod)
+ if periodCount.Cmp(common.Big1) > 0 {
+ // diff = diff + 2^(periodCount - 2)
+ expDiff := periodCount.Sub(periodCount, common.Big2)
+ expDiff.Exp(common.Big2, expDiff, nil)
+ diff.Add(diff, expDiff)
+ diff = common.BigMax(diff, params.MinimumDifficulty)
+ }
+
return diff
}
diff --git a/core/chain_util_test.go b/core/chain_util_test.go
new file mode 100644
index 000000000..4bbe81194
--- /dev/null
+++ b/core/chain_util_test.go
@@ -0,0 +1,77 @@
+// Copyright 2015 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 core
+
+import (
+ "encoding/json"
+ "math/big"
+ "os"
+ "testing"
+
+ "github.com/ethereum/go-ethereum/common"
+)
+
+type diffTest struct {
+ ParentTimestamp uint64
+ ParentDifficulty *big.Int
+ CurrentTimestamp uint64
+ CurrentBlocknumber *big.Int
+ CurrentDifficulty *big.Int
+}
+
+func (d *diffTest) UnmarshalJSON(b []byte) (err error) {
+ var ext struct {
+ ParentTimestamp string
+ ParentDifficulty string
+ CurrentTimestamp string
+ CurrentBlocknumber string
+ CurrentDifficulty string
+ }
+ if err := json.Unmarshal(b, &ext); err != nil {
+ return err
+ }
+
+ d.ParentTimestamp = common.String2Big(ext.ParentTimestamp).Uint64()
+ d.ParentDifficulty = common.String2Big(ext.ParentDifficulty)
+ d.CurrentTimestamp = common.String2Big(ext.CurrentTimestamp).Uint64()
+ d.CurrentBlocknumber = common.String2Big(ext.CurrentBlocknumber)
+ d.CurrentDifficulty = common.String2Big(ext.CurrentDifficulty)
+
+ return nil
+}
+
+func TestDifficulty(t *testing.T) {
+ file, err := os.Open("../tests/files/BasicTests/difficulty.json")
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer file.Close()
+
+ tests := make(map[string]diffTest)
+ err = json.NewDecoder(file).Decode(&tests)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ for name, test := range tests {
+ number := new(big.Int).Sub(test.CurrentBlocknumber, big.NewInt(1))
+ diff := CalcDifficulty(test.CurrentTimestamp, test.ParentTimestamp, number, test.ParentDifficulty)
+ if diff.Cmp(test.CurrentDifficulty) != 0 {
+ t.Error(name, "failed. Expected", test.CurrentDifficulty, "and calculated", diff)
+ }
+ }
+}
diff --git a/miner/worker.go b/miner/worker.go
index 7fb40af78..d6d96601e 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -444,7 +444,7 @@ func (self *worker) commitNewWork() {
header := &types.Header{
ParentHash: parent.Hash(),
Number: num.Add(num, common.Big1),
- Difficulty: core.CalcDifficulty(uint64(tstamp), parent.Time(), parent.Difficulty()),
+ Difficulty: core.CalcDifficulty(uint64(tstamp), parent.Time(), parent.Number(), parent.Difficulty()),
GasLimit: core.CalcGasLimit(parent),
GasUsed: new(big.Int),
Coinbase: self.coinbase,
diff --git a/tests/files/BasicTests/difficulty.json b/tests/files/BasicTests/difficulty.json
new file mode 100644
index 000000000..44beac5f5
--- /dev/null
+++ b/tests/files/BasicTests/difficulty.json
@@ -0,0 +1,100 @@
+{
+ "preExpDiffIncrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "43",
+ "currentBlockNumber" : "42",
+ "currentDifficulty" : "1000488"
+ },
+ "preExpDiffDecrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "60",
+ "currentBlockNumber" : "42",
+ "currentDifficulty" : "999512"
+ },
+ "ExpDiffAtBlock200000Increase" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "43",
+ "currentBlockNumber" : "200000",
+ "currentDifficulty" : "1000489"
+ },
+ "ExpDiffAtBlock200000Decrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "60",
+ "currentBlockNumber" : "200000",
+ "currentDifficulty" : "999513"
+ },
+ "ExpDiffPostBlock200000Increase" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "43",
+ "currentBlockNumber" : "200001",
+ "currentDifficulty" : "1000489"
+ },
+ "ExpDiffPostBlock200000Decrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "60",
+ "currentBlockNumber" : "200001",
+ "currentDifficulty" : "999513"
+ },
+ "ExpDiffPreBlock300000Increase" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "43",
+ "currentBlockNumber" : "299999",
+ "currentDifficulty" : "1000489"
+ },
+ "ExpDiffPreBlock300000Decrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "60",
+ "currentBlockNumber" : "299999",
+ "currentDifficulty" : "999513"
+ },
+ "ExpDiffAtBlock300000Increase" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "43",
+ "currentBlockNumber" : "300000",
+ "currentDifficulty" : "1000490"
+ },
+ "ExpDiffAtBlock300000Decrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "60",
+ "currentBlockNumber" : "300000",
+ "currentDifficulty" : "999514"
+ },
+ "ExpDiffPostBlock300000Increase" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "43",
+ "currentBlockNumber" : "300001",
+ "currentDifficulty" : "1000490"
+ },
+ "ExpDiffPostBlock300000Decrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "60",
+ "currentBlockNumber" : "300001",
+ "currentDifficulty" : "999514"
+ },
+ "ExpDiffInAYearIncrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "43",
+ "currentBlockNumber" : "2302400",
+ "currentDifficulty" : "3097640"
+ },
+ "ExpDiffInAYearDecrease" : {
+ "parentTimestamp" : "42",
+ "parentDifficulty" : "1000000",
+ "currentTimestamp" : "60",
+ "currentBlockNumber" : "2302400",
+ "currentDifficulty" : "3096664"
+ }
+}
--
GitLab