core: fix stuffs (#401)

* Remove block recycling mechanism
* Return directly when previous DKG is not finished.
* Adjust some logging level
* Skip pulling when hashes to pull is empty

6 files changed, 17 insertions, 35 deletions

diff --git a/core/blockpool.go b/core/blockpool.go
index fbd84f2..4e41aa7 100644
--- a/core/blockpool.go
+++ b/core/blockpool.go
@@ -29,8 +29,8 @@ type blockPool []types.ByPosition
 
 func newBlockPool(chainNum uint32) (pool blockPool) {
 	pool = make(blockPool, chainNum)
-	for _, p := range pool {
-		heap.Init(&p)
+	for i := range pool {
+		heap.Init(&pool[i])
 	}
 	return
 }
diff --git a/core/configuration-chain.go b/core/configuration-chain.go
index a4636cb..4938ba0 100644
--- a/core/configuration-chain.go
+++ b/core/configuration-chain.go
@@ -91,6 +91,8 @@ func (cc *configurationChain) registerDKG(round uint64, threshold int) {
 	defer cc.dkgLock.Unlock()
 	if cc.dkg != nil {
 		cc.logger.Error("Previous DKG is not finished")
+		// TODO(mission): do we have to retry DKG initiation here?
+		return
 	}
 	dkgSet, err := cc.cache.GetDKGSet(round)
 	if err != nil {
diff --git a/core/consensus.go b/core/consensus.go
index faadbe9..0e5a1fb 100644
--- a/core/consensus.go
+++ b/core/consensus.go
@@ -1015,8 +1015,11 @@ func (con *Consensus) pullRandomness() {
 		case <-time.After(1500 * time.Millisecond):
 			// TODO(jimmy): pulling period should be related to lambdaBA.
 			hashes := con.ccModule.pendingBlocksWithoutRandomness()
-			con.logger.Debug("Calling Network.PullRandomness", "blocks", hashes)
-			con.network.PullRandomness(hashes)
+			if len(hashes) > 0 {
+				con.logger.Debug(
+					"Calling Network.PullRandomness", "blocks", hashes)
+				con.network.PullRandomness(hashes)
+			}
 		}
 	}
 }
diff --git a/core/syncer/agreement.go b/core/syncer/agreement.go
index 08be77a..9b351ea 100644
--- a/core/syncer/agreement.go
+++ b/core/syncer/agreement.go
@@ -99,7 +99,7 @@ func (a *agreement) processBlock(b *types.Block) {
 func (a *agreement) processAgreementResult(r *types.AgreementResult) {
 	// Cache those results that CRS is not ready yet.
 	if _, exists := a.confirmedBlocks[r.BlockHash]; exists {
-		a.logger.Debug("agreement result already confirmed", "result", r)
+		a.logger.Trace("agreement result already confirmed", "result", r)
 		return
 	}
 	if r.Position.Round > a.latestCRSRound {
@@ -109,7 +109,7 @@ func (a *agreement) processAgreementResult(r *types.AgreementResult) {
 			a.pendings[r.Position.Round] = pendingsForRound
 		}
 		pendingsForRound[r.BlockHash] = r
-		a.logger.Debug("agreement result cached", "result", r)
+		a.logger.Trace("agreement result cached", "result", r)
 		return
 	}
 	if err := core.VerifyAgreementResult(r, a.cache); err != nil {
diff --git a/core/syncer/consensus.go b/core/syncer/consensus.go
index 8852a47..92f8fd8 100644
--- a/core/syncer/consensus.go
+++ b/core/syncer/consensus.go
@@ -262,12 +262,12 @@ func (con *Consensus) ensureAgreementOverlapRound() bool {
 		for r = range tipRoundMap {
 			break
 		}
-		con.logger.Info("check agreement round cut",
+		con.logger.Debug("check agreement round cut",
 			"tip-round", r,
 			"configs", len(con.configs))
 		if tipRoundMap[r] == con.configs[r].NumChains {
 			con.agreementRoundCut = r
-			con.logger.Debug("agreement round cut found, round", r)
+			con.logger.Info("agreement round cut found, round", r)
 			return true
 		}
 	}
@@ -416,7 +416,7 @@ func (con *Consensus) SyncBlocks(
 			"expected", tipHeight+1)
 		return false, ErrInvalidSyncingFinalizationHeight
 	}
-	con.logger.Debug("syncBlocks",
+	con.logger.Trace("syncBlocks",
 		"position", &blocks[0].Position,
 		"final height", blocks[0].Finalization.Height,
 		"len", len(blocks),
@@ -601,7 +601,7 @@ func (con *Consensus) setupConfigs(blocks []*types.Block) {
 			maxRound = b.Position.Round
 		}
 	}
-	con.logger.Info("syncer setupConfigs",
+	con.logger.Debug("syncer setupConfigs",
 		"max", maxRound,
 		"lattice", con.latticeLastRound)
 	// Get configs from governance.
@@ -737,7 +737,7 @@ func (con *Consensus) startCRSMonitor() {
 		if round == lastNotifiedRound {
 			return
 		}
-		con.logger.Info("CRS is ready", "round", round)
+		con.logger.Debug("CRS is ready", "round", round)
 		lastNotifiedRound = round
 		for _, a := range con.agreements {
 			a.inputChan <- round
diff --git a/core/types/block.go b/core/types/block.go
index f42b702..b2a8f57 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -24,7 +24,6 @@ import (
 	"fmt"
 	"io"
 	"sort"
-	"sync"
 	"time"
 
 	"github.com/dexon-foundation/dexon/rlp"
@@ -47,15 +46,6 @@ const (
 	VerifyInvalidBlock
 )
 
-var (
-	// blockPool is the blocks cache to reuse allocated blocks.
-	blockPool = sync.Pool{
-		New: func() interface{} {
-			return &Block{}
-		},
-	}
-)
-
 type rlpTimestamp struct {
 	time.Time
 }
@@ -133,19 +123,6 @@ type Witness struct {
 	Data   []byte `json:"data"`
 }
 
-// RecycleBlock put unused block into cache, which might be reused if
-// not garbage collected.
-func RecycleBlock(b *Block) {
-	blockPool.Put(b)
-}
-
-// NewBlock initiate a block.
-func NewBlock() (b *Block) {
-	b = blockPool.Get().(*Block)
-	b.Acks = b.Acks[:0]
-	return
-}
-
 // Block represents a single event broadcasted on the network.
 type Block struct {
 	ProposerID   NodeID              `json:"proposer_id"`
@@ -226,7 +203,7 @@ func (b *Block) String() string {
 
 // Clone returns a deep copy of a block.
 func (b *Block) Clone() (bcopy *Block) {
-	bcopy = NewBlock()
+	bcopy = &Block{}
 	bcopy.ProposerID = b.ProposerID
 	bcopy.ParentHash = b.ParentHash
 	bcopy.Hash = b.Hash