Merge pull request #212 from iquidus/dev/dag-pregen

1099 miner DAG pre-generation fix

consensus/ethash/algorithm_test.go

@@ -40,6 +40,32 @@ func prepare(dest []uint32, src []byte) {
 	}
 }
 
+// Tests whether calcEpoch returns the correct epoch
+func TestCalcEpoch(t *testing.T) {
+	blockNum := uint64(120000)
+	want := uint64(blockNum / epochLengthDefault)
+	if epoch := calcEpoch(blockNum, epochLengthDefault); epoch != want {
+		t.Errorf("epoch: epoch mismatch: have %d, want %d", epoch, want)
+	}
+	want = uint64(blockNum / epochLengthECIP1099)
+	if epoch := calcEpoch(blockNum, epochLengthECIP1099); epoch != want {
+		t.Errorf("epoch: epoch mismatch: have %d, want %d", epoch, want)
+	}
+}
+
+// Tests whether calcEpochLength returns the correct epoch length
+func TestCalcEpochLength(t *testing.T) {
+	ecip1099FBlock := uint64(2520000) // mordor
+	epochLength := calcEpochLength(uint64(ecip1099FBlock-1), &ecip1099FBlock)
+	if epochLength != epochLengthDefault {
+		t.Errorf("epoch: length mismatch: have %d, want %d", epochLength, epochLengthDefault)
+	}
+	epochLength = calcEpochLength(ecip1099FBlock, &ecip1099FBlock)
+	if epochLength != epochLengthECIP1099 {
+		t.Errorf("epoch: length mismatch: have %d, want %d", epochLength, epochLengthECIP1099)
+	}
+}
+
 // Tests whether the dataset size calculator works correctly by cross checking the
 // hard coded lookup table with the value generated by it.
 func TestSizeCalculations(t *testing.T) {

consensus/ethash/ethash.go

@@ -179,7 +179,7 @@ func newlru(what string, maxItems int, new func(epoch uint64, epochLength uint64
 // get retrieves or creates an item for the given epoch. The first return value is always
 // non-nil. The second return value is non-nil if lru thinks that an item will be useful in
 // the near future.
-func (lru *lru) get(epoch uint64, epochLength uint64) (item, future interface{}) {
+func (lru *lru) get(epoch uint64, epochLength uint64, ecip1099FBlock *uint64) (item, future interface{}) {
 	lru.mu.Lock()
 	defer lru.mu.Unlock()
 
@@ -194,11 +194,23 @@ func (lru *lru) get(epoch uint64, epochLength uint64) (item, future interface{})
 		}
 		lru.cache.Add(epoch, item)
 	}
+
+	// Ensure pre-generation handles ecip-1099 changeover correctly
+	var nextEpoch = epoch + 1
+	var nextEpochLength = epochLength
+	if ecip1099FBlock != nil {
+		nextEpochBlock := nextEpoch * epochLength
+		if nextEpochBlock == *ecip1099FBlock && epochLength == epochLengthDefault {
+			nextEpoch = nextEpoch / 2
+			nextEpochLength = epochLengthECIP1099
+		}
+	}
+
 	// Update the 'future item' if epoch is larger than previously seen.
-	if epoch < maxEpoch-1 && lru.future < epoch+1 {
-		log.Trace("Requiring new future ethash "+lru.what, "epoch", epoch+1)
-		future = lru.new(epoch+1, epochLength)
-		lru.future = epoch + 1
+	if epoch < maxEpoch-1 && lru.future < nextEpoch {
+		log.Trace("Requiring new future ethash "+lru.what, "epoch", nextEpoch)
+		future = lru.new(nextEpoch, nextEpochLength)
+		lru.future = nextEpoch
 		lru.futureItem = future
 	}
 	return item, future
@@ -561,7 +573,7 @@ func (ethash *Ethash) Close() error {
 func (ethash *Ethash) cache(block uint64) *cache {
 	epochLength := calcEpochLength(block, ethash.config.ECIP1099Block)
 	epoch := calcEpoch(block, epochLength)
-	currentI, futureI := ethash.caches.get(epoch, epochLength)
+	currentI, futureI := ethash.caches.get(epoch, epochLength, ethash.config.ECIP1099Block)
 	current := currentI.(*cache)
 
 	// Wait for generation finish.
@@ -585,7 +597,7 @@ func (ethash *Ethash) dataset(block uint64, async bool) *dataset {
 	// Retrieve the requested ethash dataset
 	epochLength := calcEpochLength(block, ethash.config.ECIP1099Block)
 	epoch := calcEpoch(block, epochLength)
-	currentI, futureI := ethash.datasets.get(epoch, epochLength)
+	currentI, futureI := ethash.datasets.get(epoch, epochLength, ethash.config.ECIP1099Block)
 	current := currentI.(*dataset)
 
 	// If async is specified, generate everything in a background thread

consensus/ethash/ethash_test.go

@@ -18,6 +18,7 @@ package ethash
 
 import (
 	"io/ioutil"
+	"math"
 	"math/big"
 	"math/rand"
 	"os"
@@ -30,6 +31,56 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 )
 
+// Tests caches get sets correct future
+func TestCachesGet(t *testing.T) {
+	ethashA := NewTester(nil, false)
+	defer ethashA.Close()
+
+	ethashB := NewTester(nil, false)
+	defer ethashB.Close()
+
+	ethashC := NewTester(nil, false)
+	defer ethashC.Close()
+
+	var (
+		epoch             uint64 = 83
+		ecip1099Block     uint64 = 2520000
+		nextEpochDefault  uint64 = 84
+		nextEpochECIP1099 uint64 = 42
+		maxUint64         uint64 = math.MaxUint64
+	)
+	// test without ecip-1099 enabled
+	currentIA, futureIA := ethashA.caches.get(epoch, epochLengthDefault, &maxUint64)
+	currentA := currentIA.(*cache)
+	if currentA.epoch != epoch {
+		t.Errorf("cache: current epoch mismatch: have %d, want %d", currentA.epoch, epoch)
+	}
+	futureA := futureIA.(*cache)
+	if futureA.epoch != nextEpochDefault {
+		t.Errorf("cache: future epoch mismatch: have %d, want %d", futureA.epoch, nextEpochDefault)
+	}
+	// test activation boundary of ecip-1099
+	currentIB, futureIB := ethashB.caches.get(epoch, epochLengthDefault, &ecip1099Block)
+	currentB := currentIB.(*cache)
+	if currentB.epoch != epoch {
+		t.Errorf("cache: current epoch mismatch: have %d, want %d", currentB.epoch, epoch)
+	}
+	futureB := futureIB.(*cache)
+	if futureB.epoch != nextEpochECIP1099 {
+		t.Errorf("cache: future epoch mismatch: have %d, want %d", futureB.epoch, nextEpochECIP1099)
+	}
+	// test post ecip-1099 activation
+	currentIC, futureIC := ethashC.caches.get(nextEpochECIP1099, epochLengthECIP1099, &ecip1099Block)
+	currentC := currentIC.(*cache)
+	if currentC.epoch != nextEpochECIP1099 {
+		t.Errorf("cache: current epoch mismatch: have %d, want %d", currentC.epoch, nextEpochECIP1099)
+	}
+	futureC := futureIC.(*cache)
+	if futureC.epoch != nextEpochECIP1099+1 {
+		t.Errorf("cache: future epoch mismatch: have %d, want %d", futureC.epoch, nextEpochECIP1099+1)
+	}
+}
+
 // Tests that ethash works correctly in test mode.
 func TestTestMode(t *testing.T) {
 	header := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}