diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 9e92f00950..15db979823 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -123,7 +123,7 @@ var (
 	}
 	DiffSyncFlag = cli.BoolFlag{
 		Name: "diffsync",
-		Usage: "Enable difflayer sync, Please note that enable diffsync will improve the syncing speed, " +
+		Usage: "Enable diffy sync, Please note that enable diffsync will improve the syncing speed, " +
 			"but will degrade the security to light client level",
 	}
 	RangeLimitFlag = cli.BoolFlag{
diff --git a/consensus/parlia/parlia.go b/consensus/parlia/parlia.go
index 275ad2b913..9e599cdbd8 100644
--- a/consensus/parlia/parlia.go
+++ b/consensus/parlia/parlia.go
@@ -55,8 +55,7 @@ const (
 
 	validatorBytesLength = common.AddressLength
 	wiggleTime           = uint64(1) // second, Random delay (per signer) to allow concurrent signers
-	// TODO this is a hardfork change, just for tuning so far, recover it late
-	initialBackOffTime = uint64(2) // second
+	initialBackOffTime   = uint64(1) // second
 
 	systemRewardPercent = 4 // it means 1/2^4 = 1/16 percentage of gas fee incoming will be distributed to system
 
@@ -800,9 +799,9 @@ func (p *Parlia) Delay(chain consensus.ChainReader, header *types.Header) *time.
 		return nil
 	}
 	delay := p.delayForRamanujanFork(snap, header)
-	// The blocking time should be no more than half of epoch
-	if delay > time.Duration(p.config.Period)*time.Second*4/5 {
-		delay = time.Duration(p.config.Period) * time.Second * 4 / 5
+	// The blocking time should be no more than half of period
+	if delay > time.Duration(p.config.Period)*time.Second/2 {
+		delay = time.Duration(p.config.Period) * time.Second / 2
 	}
 	return &delay
 }
@@ -894,19 +893,9 @@ func (p *Parlia) AllowLightProcess(chain consensus.ChainReader, currentHeader *t
 	}
 
 	idx := snap.indexOfVal(p.val)
-	if idx < 0 {
-		return true
-	}
-	validators := snap.validators()
-
-	validatorNum := int64(len(validators))
-	// It is not allowed if only two validators
-	if validatorNum <= 2 {
-		return false
-	}
+	// validator is not allowed to diff sync
+	return idx < 0
 
-	offset := (int64(snap.Number) + 2) % validatorNum
-	return validators[offset] == p.val
 }
 
 func (p *Parlia) IsLocalBlock(header *types.Header) bool {
diff --git a/core/blockchain.go b/core/blockchain.go
index 84a229f629..fbf7fc00f6 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -2654,14 +2654,12 @@ func (bc *BlockChain) HandleDiffLayer(diffLayer *types.DiffLayer, pid string, fu
 		if _, alreadyHas := bc.diffPeersToDiffHashes[pid][diffLayer.DiffHash]; alreadyHas {
 			return nil
 		}
+	} else {
+		bc.diffPeersToDiffHashes[pid] = make(map[common.Hash]struct{})
 	}
-	bc.diffPeersToDiffHashes[pid] = make(map[common.Hash]struct{})
 	bc.diffPeersToDiffHashes[pid][diffLayer.DiffHash] = struct{}{}
 	if _, exist := bc.diffNumToBlockHashes[diffLayer.Number]; !exist {
 		bc.diffNumToBlockHashes[diffLayer.Number] = make(map[common.Hash]struct{})
-	}
-	if len(bc.diffNumToBlockHashes[diffLayer.Number]) > 4 {
-
 	}
 	bc.diffNumToBlockHashes[diffLayer.Number][diffLayer.BlockHash] = struct{}{}
 
@@ -2929,7 +2927,7 @@ func (bc *BlockChain) SubscribeBlockProcessingEvent(ch chan<- bool) event.Subscr
 	return bc.scope.Track(bc.blockProcFeed.Subscribe(ch))
 }
 
-//Options
+// Options
 func EnableLightProcessor(bc *BlockChain) *BlockChain {
 	bc.processor = NewLightStateProcessor(bc.Config(), bc, bc.engine)
 	return bc
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 886f181bf5..b55171e324 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -1109,9 +1109,11 @@ func (s *StateDB) LightCommit(root common.Hash) (common.Hash, *types.DiffLayer,
 			tasksNum := 0
 			finishCh := make(chan struct{})
 			defer close(finishCh)
-			threads := 1
-			if len(s.diffTries)/runtime.NumCPU() > minNumberOfAccountPerTask {
+			threads := len(s.diffTries) / minNumberOfAccountPerTask
+			if threads > runtime.NumCPU() {
 				threads = runtime.NumCPU()
+			} else if threads == 0 {
+				threads = 1
 			}
 			for i := 0; i < threads; i++ {
 				go func() {
@@ -1230,7 +1232,15 @@ func (s *StateDB) Commit(deleteEmptyObjects bool) (common.Hash, *types.DiffLayer
 			tasksNum := 0
 			finishCh := make(chan struct{})
 			defer close(finishCh)
-			for i := 0; i < runtime.NumCPU(); i++ {
+
+			threads := len(s.stateObjectsDirty) / minNumberOfAccountPerTask
+			if threads > runtime.NumCPU() {
+				threads = runtime.NumCPU()
+			} else if threads == 0 {
+				threads = 1
+			}
+
+			for i := 0; i < threads; i++ {
 				go func() {
 					codeWriter := s.db.TrieDB().DiskDB().NewBatch()
 					for {
diff --git a/core/state_processor.go b/core/state_processor.go
index aca43b4609..fb82727d0c 100644
--- a/core/state_processor.go
+++ b/core/state_processor.go
@@ -44,7 +44,9 @@ import (
 const (
 	fullProcessCheck          = 21 // On diff sync mode, will do full process every fullProcessCheck randomly
 	minNumberOfAccountPerTask = 5
-	diffLayerTimeout          = 50
+	recentTime                = 2048 * 3
+	recentDiffLayerTimeout    = 20
+	farDiffLayerTimeout       = 2
 )
 
 // StateProcessor is a basic Processor, which takes care of transitioning
@@ -83,7 +85,6 @@ func (p *LightStateProcessor) Process(block *types.Block, statedb *state.StateDB
 	allowLightProcess := true
 	if posa, ok := p.engine.(consensus.PoSA); ok {
 		allowLightProcess = posa.AllowLightProcess(p.bc, block.Header())
-		log.Error("===debug, allow to light process?", "allow", allowLightProcess)
 	}
 	// random fallback to full process
 	if check := p.randomGenerator.Int63n(fullProcessCheck); allowLightProcess && check != 0 && len(block.Transactions()) != 0 {
@@ -92,28 +93,25 @@ func (p *LightStateProcessor) Process(block *types.Block, statedb *state.StateDB
 			pid = peer.ID()
 		}
 		var diffLayer *types.DiffLayer
-		//TODO This is just for debug
+		var diffLayerTimeout = recentDiffLayerTimeout
+		if time.Now().Unix()-int64(block.Time()) > recentTime {
+			diffLayerTimeout = farDiffLayerTimeout
+		}
 		for tried := 0; tried < diffLayerTimeout; tried++ {
 			// wait a bit for the diff layer
 			diffLayer = p.bc.GetUnTrustedDiffLayer(block.Hash(), pid)
 			if diffLayer != nil {
-				log.Error("===debug find it", "idx", tried)
 				break
 			}
 			time.Sleep(time.Millisecond)
 		}
 		if diffLayer != nil {
-			if err := diffLayer.Receipts.DeriveFields(p.bc.chainConfig, block.Hash(), block.NumberU64(), block.Transactions()); err != nil {
-				log.Error("Failed to derive block receipts fields", "hash", block.Hash(), "number", block.NumberU64(), "err", err)
-				// fallback to full process
-				return p.StateProcessor.Process(block, statedb, cfg)
-			}
-			receipts, logs, gasUsed, err := p.LightProcess(diffLayer, block, statedb, cfg)
+			receipts, logs, gasUsed, err := p.LightProcess(diffLayer, block, statedb)
 			if err == nil {
 				log.Info("do light process success at block", "num", block.NumberU64())
 				return statedb, receipts, logs, gasUsed, nil
 			} else {
-				log.Error("do light process err at block\n", "num", block.NumberU64(), "err", err)
+				log.Error("do light process err at block", "num", block.NumberU64(), "err", err)
 				p.bc.removeDiffLayers(diffLayer.DiffHash)
 				// prepare new statedb
 				statedb.StopPrefetcher()
@@ -131,7 +129,7 @@ func (p *LightStateProcessor) Process(block *types.Block, statedb *state.StateDB
 	return p.StateProcessor.Process(block, statedb, cfg)
 }
 
-func (p *LightStateProcessor) LightProcess(diffLayer *types.DiffLayer, block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, uint64, error) {
+func (p *LightStateProcessor) LightProcess(diffLayer *types.DiffLayer, block *types.Block, statedb *state.StateDB) (types.Receipts, []*types.Log, uint64, error) {
 	statedb.MarkLightProcessed()
 	fullDiffCode := make(map[common.Hash][]byte, len(diffLayer.Codes))
 	diffTries := make(map[common.Address]state.Trie)
@@ -149,9 +147,11 @@ func (p *LightStateProcessor) LightProcess(diffLayer *types.DiffLayer, block *ty
 	for des := range snapDestructs {
 		statedb.Trie().TryDelete(des[:])
 	}
-	threads := 1
-	if len(snapAccounts)/runtime.NumCPU() > minNumberOfAccountPerTask {
+	threads := len(snapAccounts) / minNumberOfAccountPerTask
+	if threads > runtime.NumCPU() {
 		threads = runtime.NumCPU()
+	} else if threads == 0 {
+		threads = 1
 	}
 
 	iteAccounts := make([]common.Address, 0, len(snapAccounts))
@@ -236,7 +236,7 @@ func (p *LightStateProcessor) LightProcess(diffLayer *types.DiffLayer, block *ty
 					!bytes.Equal(latestAccount.CodeHash, types.EmptyCodeHash) {
 					if code, exist := fullDiffCode[codeHash]; exist {
 						if crypto.Keccak256Hash(code) != codeHash {
-							errChan <- err
+							errChan <- fmt.Errorf("code and code hash mismatch, account %s", diffAccount.String())
 							return
 						}
 						diffMux.Lock()
@@ -245,7 +245,7 @@ func (p *LightStateProcessor) LightProcess(diffLayer *types.DiffLayer, block *ty
 					} else {
 						rawCode := rawdb.ReadCode(p.bc.db, codeHash)
 						if len(rawCode) == 0 {
-							errChan <- err
+							errChan <- fmt.Errorf("missing code, account %s", diffAccount.String())
 							return
 						}
 					}
diff --git a/core/tx_pool.go b/core/tx_pool.go
index d0304857c3..cff0811870 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -1019,6 +1019,7 @@ func (pool *TxPool) scheduleReorgLoop() {
 			pool.reorgDoneCh <- nextDone
 
 		case req := <-pool.reqPromoteCh:
+			log.Error("=== debug receive reqPromote notice")
 			// Promote request: update address set if request is already pending.
 			if dirtyAccounts == nil {
 				dirtyAccounts = req
diff --git a/eth/handler.go b/eth/handler.go
index e4980b939b..0fd0e5d49f 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -486,7 +486,6 @@ func (h *handler) BroadcastBlock(block *types.Block, propagate bool) {
 		for _, peer := range transfer {
 			if len(diff) != 0 && peer.diffExt != nil {
 				// difflayer should send before block
-				log.Error("===debug Broadcast block", "number", block.Number(), "hash", hash)
 				peer.diffExt.SendDiffLayers([]rlp.RawValue{diff})
 			}
 			peer.AsyncSendNewBlock(block, td)
diff --git a/eth/handler_diff.go b/eth/handler_diff.go
index ab9363e6e5..97474f5f18 100644
--- a/eth/handler_diff.go
+++ b/eth/handler_diff.go
@@ -19,8 +19,6 @@ package eth
 import (
 	"fmt"
 
-	"github.com/ethereum/go-ethereum/log"
-
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/eth/protocols/diff"
 	"github.com/ethereum/go-ethereum/p2p/enode"
@@ -73,15 +71,8 @@ func (h *diffHandler) handleDiffLayerPackage(packet *diff.DiffLayersPacket, pid
 	diffs, err := packet.Unpack()
 
 	if err != nil {
-		log.Error("====unpack err", "number", diffs[0].Number, "hash", diffs[0].BlockHash, "err", err)
 		return err
 	}
-	if len(diffs) > 0 {
-		log.Error("====debug receive difflayer", "number", diffs[0].Number, "hash", diffs[0].BlockHash)
-
-	} else {
-		log.Error("====debug receive difflayer length 0")
-	}
 	for _, d := range diffs {
 		if d != nil {
 			if err := d.Validate(); err != nil {
diff --git a/eth/protocols/diff/protocol.go b/eth/protocols/diff/protocol.go
index 02474632a5..ad35228cc8 100644
--- a/eth/protocols/diff/protocol.go
+++ b/eth/protocols/diff/protocol.go
@@ -98,6 +98,7 @@ func (p *DiffLayersPacket) Unpack() ([]*types.DiffLayer, error) {
 
 type DiffCapPacket struct {
 	DiffSync bool
+	//Extra    rlp.RawValue // for extension
 }
 
 type DiffLayersPacket []rlp.RawValue