diff --git a/ChangeLog b/ChangeLog
index 7095f6f5..58c17995 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,86 @@
+2006-05-20  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
+
+	To add the ability to download several pieces in mix in a command and
+	increase the number of request slots according to request-cancel
+	latency:
+	
+	* src/PeerInteractionCommand.cc
+	(executeInternal): The number of messages to be received at a time
+	is increased from 10 to 50.
+	* src/LogFactory
+	(getInstance): Added NullLogger.
+	* src/NullLogger.h: New class.
+	* src/BitfieldMan.h
+	(getMissingIndex): New function.
+	* src/BitfieldMan.cc
+	(getMissingIndex): New function.
+	* src/TorrentMan.h
+	(checkOutPiece): New function.
+	(getMissingPieceIndex): New function.
+	(getMissingFastPieceIndex): New function.
+	(getMissingFastPiece): New function.
+	* src/TorrentMan.cc
+	(updatePiece): Rewritten using STL.
+	(syncPiece): Rewritten using STL.
+	(getMissingPiece): Rewritten using getMissingPieceIndex() and
+	checkOutPiece().
+	(getMissingPieceIndex): New function.
+	(getMissingFastPieceIndex): New function.
+	(getMissingFastPiece): New function.
+	(checkOutPiece): New function.
+	* src/PeerInteraction.h
+	(Pieces): New type definition.
+	(piece): Removed.
+	(pieces): New variable.
+	(getNewPieceAndSendInterest): Added the "piece" argument.
+	(abortPiece): Added the "piece" argument.
+	(abortAllPieces): New function.
+	(isInRequestSlot): New function.
+	(hasDownloadPiece): Added the "index" argument.
+	(setDownloadPiece): Removed.
+	(getDownloadPiece): Added the "index" argument.
+	(updatePiece): New function.
+	(createRequestMessage): Added the "index" argument.
+	* src/PeerInteraction.cc
+	(onChoked): Rewritten.
+	(abortPiece): Rewirtten.
+	(abortAllPieces): New function.
+	(deleteTimeoutRequestSlot): Rewritten.
+	Clarified code a little bit.
+	(deleteCompletedRequestSlot): Rewritten.
+	(isInRequestSlot): New function.
+	(syncPiece): Rewritten.
+	(updatePiece): New function.
+	(getNewPieceAndSendInterest): Rewritten.
+	(addRequests):  Rewritten.
+	(getDownloadPiece): Rewritten.
+	(hasDownloadPiece): Rewritten.
+	(createRequestMessage): Added the "index" argument.
+	* src/common.h
+	(BITFIELD_LEN_FROM_PIECES): Enclosed the variable in parentheses.
+	(DIV_FLOOR): New definition.
+	* src/PieceMessage.cc
+	(receivedAction): Update request-piece latency here.
+	* src/RequestSlot.h
+	(getLatencyInMillis): New function.
+	* src/RequestSlot.cc
+	(isTimeout): Rewritten using getLatencyInMillis.
+	(getLatencyInMillis): New function.
+	* src/Piece.h
+	(operator==): New function.
+	(getMissingBlockIndex): New function.
+	* src/Piece.cc
+	(operator==): New function.
+	(getMissingBlockIndex): New function.
+	* src/Peer.h
+	(DEFAULT_LATENCY): New definition.
+	(latency): New variable.
+	(updateLatency): New function.
+	(getLatency): New function.
+	* src/Peer.cc
+	(resetStatus): Reset latecy.
+	(updateLatency): New function.
+	
 2006-05-20  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
 
 	* src/SocketCore.cc
diff --git a/src/BitfieldMan.cc b/src/BitfieldMan.cc
index 9ae3276c..c5c120f9 100644
--- a/src/BitfieldMan.cc
+++ b/src/BitfieldMan.cc
@@ -192,6 +192,20 @@ int BitfieldMan::getFirstMissingUnusedIndex() const {
   return -1;
 }
 
+int BitfieldMan::getMissingIndex() const {
+  unsigned char* tempBitfield = new unsigned char[bitfieldLength];
+  for(int i = 0; i < bitfieldLength; i++) {
+    tempBitfield[i] = ~bitfield[i];
+    if(filterEnabled) {
+      tempBitfield[i] &= filterBitfield[i];
+    }
+  }
+  int max = countSetBit(tempBitfield, bitfieldLength);
+  int index = getMissingIndexRandomly(tempBitfield, bitfieldLength, max);
+  delete [] tempBitfield;
+  return index;
+}
+
 BlockIndexes BitfieldMan::getAllMissingIndexes() const {
   BlockIndexes missingIndexes;
   for(int i = 0; i < bitfieldLength; i++) {
diff --git a/src/BitfieldMan.h b/src/BitfieldMan.h
index f329a52f..7c9a9522 100644
--- a/src/BitfieldMan.h
+++ b/src/BitfieldMan.h
@@ -68,6 +68,10 @@ public:
    * affected by filter
    */
   int getMissingIndex(const unsigned char* bitfield, int len) const;
+  /**
+   * affected by filter
+   */
+  int getMissingIndex() const;
   /**
    * affected by filter
    */
diff --git a/src/LogFactory.cc b/src/LogFactory.cc
index e45ae653..8bb5780f 100644
--- a/src/LogFactory.cc
+++ b/src/LogFactory.cc
@@ -21,19 +21,20 @@
 /* copyright --> */
 #include "LogFactory.h"
 #include "SimpleLogger.h"
+#include "NullLogger.h"
 
 string LogFactory::filename;
 Logger* LogFactory::logger = NULL;
 
 Logger* LogFactory::getInstance() {
   if(logger == NULL) {
-    SimpleLogger* slogger = new SimpleLogger();
     if(filename.empty()) {
-      slogger->openFile("/dev/null");
+      logger = new NullLogger();
     } else {
+      SimpleLogger* slogger = new SimpleLogger();
       slogger->openFile(filename);
+      logger = slogger;
     }
-    logger = slogger;
   }
   return logger;
 }
diff --git a/src/Makefile.am b/src/Makefile.am
index 5ac5d866..55209d41 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -100,7 +100,8 @@ SRCS =  Socket.cc Socket.h\
 	RejectMessage.cc RejectMessage.h\
 	AllowedFastMessage.cc AllowedFastMessage.h\
 	SuggestPieceMessage.cc SuggestPieceMessage.h\
-	SimplePeerMessage.cc SimplePeerMessage.h
+	SimplePeerMessage.cc SimplePeerMessage.h\
+	NullLogger.h
 noinst_LIBRARIES = libaria2c.a
 libaria2c_a_SOURCES = $(SRCS)
 aria2c_LDADD = libaria2c.a @LIBINTL@ @ALLOCA@ @LIBGNUTLS_LIBS@\
diff --git a/src/Makefile.in b/src/Makefile.in
index b61a96e9..a113ed2d 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -359,7 +359,8 @@ SRCS = Socket.cc Socket.h\
 	RejectMessage.cc RejectMessage.h\
 	AllowedFastMessage.cc AllowedFastMessage.h\
 	SuggestPieceMessage.cc SuggestPieceMessage.h\
-	SimplePeerMessage.cc SimplePeerMessage.h
+	SimplePeerMessage.cc SimplePeerMessage.h\
+	NullLogger.h
 
 noinst_LIBRARIES = libaria2c.a
 libaria2c_a_SOURCES = $(SRCS)
diff --git a/src/NullLogger.h b/src/NullLogger.h
new file mode 100644
index 00000000..e5cd69b4
--- /dev/null
+++ b/src/NullLogger.h
@@ -0,0 +1,43 @@
+/* <!-- copyright */
+/*
+ * aria2 - a simple utility for downloading files faster
+ *
+ * Copyright (C) 2006 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+/* copyright --> */
+#ifndef _D_NULL_LOGGER_H_
+#define _D_NULL_LOGGER_H_
+
+#include "Logger.h"
+
+using namespace std;
+
+class NullLogger : public Logger {
+public:
+  NullLogger() {}
+  virtual ~NullLogger() {}
+  virtual void debug(const char* msg, ...) const {}
+  virtual void debug(const char* msg, Exception* ex, ...) const {}
+  virtual void info(const char* msg, ...) const {}
+  virtual void info(const char* msg, Exception* ex, ...) const {}
+  virtual void warn(const char* msg, ...) const {}
+  virtual void warn(const char* msg, Exception* ex, ...) const {}
+  virtual void error(const char*  msg, ...) const {}
+  virtual void error(const char* msg, Exception* ex, ...) const {}
+};
+
+#endif // _D_NULL_LOGGER_H_
diff --git a/src/Peer.cc b/src/Peer.cc
index 9c83321e..28099c45 100644
--- a/src/Peer.cc
+++ b/src/Peer.cc
@@ -60,6 +60,7 @@ void Peer::resetStatus() {
   chokingRequired = true;
   optUnchoking = false;
   fastExtensionEnabled = false;
+  latency = DEFAULT_LATENCY;
   fastSet.clear();
 }
 
@@ -76,3 +77,7 @@ void Peer::addFastSetIndex(int index) {
 void Peer::setAllBitfield() {
   bitfield->setAllBit();
 }
+
+void Peer::updateLatency(int latency) {
+  this->latency = (this->latency*80+latency*20)/200;
+}
diff --git a/src/Peer.h b/src/Peer.h
index 8958170f..f87010bb 100644
--- a/src/Peer.h
+++ b/src/Peer.h
@@ -30,6 +30,7 @@
 using namespace std;
 
 #define PEER_ID_LENGTH 20
+#define DEFAULT_LATENCY 1000
 
 class Peer {
 public:
@@ -57,6 +58,7 @@ private:
   long long int totalLength;
   int deltaUpload;
   int deltaDownload;
+  int latency;
 public:
   Peer(string ipaddr, int port, int pieceLength, long long int totalLength):
     entryId(0), ipaddr(ipaddr), port(port),
@@ -68,7 +70,8 @@ public:
     fastExtensionEnabled(false),
     peerUpload(0), peerDownload(0),
     pieceLength(pieceLength), totalLength(totalLength),
-    deltaUpload(0), deltaDownload(0) {
+    deltaUpload(0), deltaDownload(0),
+    latency(DEFAULT_LATENCY) {
     this->bitfield = new BitfieldMan(pieceLength, totalLength);
   }
 
@@ -140,6 +143,9 @@ public:
 
   bool isSeeder() const;
 
+  void updateLatency(int latency);
+  int getLatency() const { return latency; }
+
   static Peer* nullPeer;
 };
 
diff --git a/src/PeerInteraction.cc b/src/PeerInteraction.cc
index 83dfd180..28fd9989 100644
--- a/src/PeerInteraction.cc
+++ b/src/PeerInteraction.cc
@@ -35,8 +35,7 @@ PeerInteraction::PeerInteraction(int cuid,
   :cuid(cuid),
    uploadLimit(0),
    torrentMan(torrentMan),
-   peer(peer),
-   piece(Piece::nullPiece) {
+   peer(peer) {
   peerConnection = new PeerConnection(cuid, socket, op);
   logger = LogFactory::getInstance();
 }
@@ -163,34 +162,51 @@ void PeerInteraction::rejectPieceMessageInQueue(int index, int begin, int length
 }
 
 void PeerInteraction::onChoked() {
-  if(!Piece::isNull(piece) && !peer->isInFastSet(piece.getIndex())) {
-    abortPiece();
+  for(Pieces::iterator itr = pieces.begin(); itr != pieces.end();) {
+    Piece& piece = *itr;
+    if(!peer->isInFastSet(piece.getIndex())) {
+      abortPiece(piece);
+      itr = pieces.erase(itr);
+    } else {
+      itr++;
+    }
   }
 }
 
-void PeerInteraction::abortPiece() {
+void PeerInteraction::abortAllPieces() {
+  for(Pieces::iterator itr = pieces.begin(); itr != pieces.end();) {
+    abortPiece(*itr);
+    itr = pieces.erase(itr);
+  }
+}
+
+void PeerInteraction::abortPiece(Piece& piece) {
   if(!Piece::isNull(piece)) {
     for(MessageQueue::iterator itr = messageQueue.begin();
 	itr != messageQueue.end();) {
-      if((*itr)->getId() == RequestMessage::ID
-	 && !(*itr)->isInProgress()) {
+      if((*itr)->getId() == RequestMessage::ID &&
+	!(*itr)->isInProgress() &&
+	 ((RequestMessage*)*itr)->getIndex() == piece.getIndex()) {
 	delete *itr;
 	itr = messageQueue.erase(itr);
       } else {
 	itr++;
       }
     }  
-    for(RequestSlots::const_iterator itr = requestSlots.begin();
-	itr != requestSlots.end(); itr++) {
-      logger->debug("CUID#%d - Deleting request slot blockIndex=%d"
-		    " because piece was canceled",
-		    cuid,
-		    itr->getBlockIndex());
-      piece.cancelBlock(itr->getBlockIndex());
+    for(RequestSlots::iterator itr = requestSlots.begin();
+	itr != requestSlots.end();) {
+      if(itr->getIndex() == piece.getIndex()) {
+	logger->debug("CUID#%d - Deleting request slot blockIndex=%d"
+		      " because piece was canceled",
+		      cuid,
+		      itr->getBlockIndex());
+	piece.cancelBlock(itr->getBlockIndex());
+	itr = requestSlots.erase(itr);
+      } else {
+	itr++;
+      }
     }
-    requestSlots.clear();
     torrentMan->cancelPiece(piece);
-    piece = Piece::nullPiece;
   }
 }
 
@@ -206,31 +222,35 @@ void PeerInteraction::deleteRequestSlot(const RequestSlot& requestSlot) {
 void PeerInteraction::deleteTimeoutRequestSlot() {
   for(RequestSlots::iterator itr = requestSlots.begin();
       itr != requestSlots.end();) {
-    if(itr->isTimeout(REQUEST_TIME_OUT)) {
+    RequestSlot& slot = *itr;
+    if(slot.isTimeout(REQUEST_TIME_OUT)) {
       logger->debug("CUID#%d - Deleting request slot blockIndex=%d"
 		    " because of time out",
 		    cuid,
-		    itr->getBlockIndex());
-      if(!Piece::isNull(piece)) {
-	piece.cancelBlock(itr->getBlockIndex());
-      }
+		    slot.getBlockIndex());
+      Piece& piece = getDownloadPiece(slot.getIndex());
+      piece.cancelBlock(slot.getBlockIndex());
       itr = requestSlots.erase(itr);
     } else {
       itr++;
     }
   }
-  torrentMan->updatePiece(piece);
+  updatePiece();
 }
 
 void PeerInteraction::deleteCompletedRequestSlot() {
   for(RequestSlots::iterator itr = requestSlots.begin();
       itr != requestSlots.end();) {
-    if(Piece::isNull(piece) || piece.hasBlock(itr->getBlockIndex()) ||
+    RequestSlot& slot = *itr;
+    Piece piece = getDownloadPiece(slot.getIndex());
+    if(piece.hasBlock(slot.getBlockIndex()) ||
        torrentMan->hasPiece(piece.getIndex())) {
       logger->debug("CUID#%d - Deleting request slot blockIndex=%d because"
 		    " the block has been acquired.", cuid,
-		    itr->getBlockIndex());
-      addMessage(createCancelMessage(itr->getIndex(), itr->getBegin(), itr->getLength()));
+		    slot.getBlockIndex());
+      addMessage(createCancelMessage(slot.getIndex(),
+				     slot.getBegin(),
+				     slot.getLength()));
       itr = requestSlots.erase(itr);
     } else {
       itr++;
@@ -238,6 +258,17 @@ void PeerInteraction::deleteCompletedRequestSlot() {
   }
 }
 
+bool PeerInteraction::isInRequestSlot(int index, int blockIndex) const {
+  for(RequestSlots::const_iterator itr = requestSlots.begin();
+      itr != requestSlots.end(); itr++) {
+    const RequestSlot& slot = *itr;
+    if(slot.getIndex() == index && slot.getBlockIndex() == blockIndex) {
+      return true;
+    }
+  }
+  return false;
+}
+
 RequestSlot PeerInteraction::getCorrespondingRequestSlot(int index,
 							 int begin,
 							 int length) const {
@@ -379,62 +410,112 @@ PeerMessage* PeerInteraction::createPeerMessage(const char* msg, int msgLength)
 
 
 void PeerInteraction::syncPiece() {
-  if(Piece::isNull(piece)) {
-    return;
+  for(Pieces::iterator itr = pieces.begin(); itr != pieces.end(); itr++) {
+    torrentMan->syncPiece(*itr);
   }
-  torrentMan->syncPiece(piece);
 }
 
-void PeerInteraction::getNewPieceAndSendInterest() {
-  piece = torrentMan->getMissingPiece(peer);
-  if(Piece::isNull(piece)) {
-    logger->debug("CUID#%d - Not interested in the peer", cuid);
-    addMessage(createNotInterestedMessage());
-  } else {
-    if(peer->peerChoking && !peer->isInFastSet(piece.getIndex())) {
-      abortPiece();
-    } else {
-      logger->info("CUID#%d - Starting download for piece index=%d (%d/%d completed)",
-		    cuid, piece.getIndex(), piece.countCompleteBlock(),
-		    piece.countBlock());
+void PeerInteraction::updatePiece() {
+  for(Pieces::iterator itr = pieces.begin(); itr != pieces.end(); itr++) {
+    torrentMan->updatePiece(*itr);
+  }
+}
+
+void PeerInteraction::getNewPieceAndSendInterest(int pieceNum) {
+  int index = torrentMan->getMissingPieceIndex(peer);
+  if(pieces.empty() && index == -1) {
+    if(peer->amInterested) {
+      logger->debug("CUID#%d - Not interested in the peer", cuid);
+      addMessage(createNotInterestedMessage());
+    }
+  } else {
+    if(peer->peerChoking) {
+      onChoked();
+      if(peer->isFastExtensionEnabled()) {
+	while((int)pieces.size() < pieceNum) {
+	  Piece piece = torrentMan->getMissingFastPiece(peer);
+	  if(Piece::isNull(piece)) {
+	    break;
+	  } else {
+	    pieces.push_back(piece);
+	  }
+	}
+      }
+    } else {
+      while((int)pieces.size() < pieceNum) {
+	Piece piece = torrentMan->getMissingPiece(peer);
+	if(Piece::isNull(piece)) {
+	  break;
+	} else {
+	  pieces.push_back(piece);
+	}
+      }
+    }
+    if(!peer->amInterested) {
+      logger->debug("CUID#%d - Interested in the peer", cuid);
+      addMessage(createInterestedMessage());
     }
-    logger->debug("CUID#%d - Interested in the peer", cuid);
-    addMessage(createInterestedMessage());
   }
 }
 
 void PeerInteraction::addRequests() {
-  if(Piece::isNull(piece)) {
-    // retrive new piece from TorrentMan
-    getNewPieceAndSendInterest();
-  } else if(peer->peerChoking && !peer->isInFastSet(piece.getIndex())) {
-    onChoked();
-  } else if(piece.pieceComplete()) {
-    abortPiece();
-    getNewPieceAndSendInterest();
+  // Abort downloading of completed piece.
+  for(Pieces::iterator itr = pieces.begin(); itr != pieces.end();) {
+    Piece& piece = *itr;
+    if(piece.pieceComplete()) {
+      abortPiece(piece);
+      itr = pieces.erase(itr);
+    } else {
+      itr++;
+    }
   }
-  if(!Piece::isNull(piece)) {
+  int MAX_PENDING_REQUEST;
+  if(peer->getLatency() < 300) {
+    MAX_PENDING_REQUEST = 24;
+  } else if(peer->getLatency() < 600) {
+    MAX_PENDING_REQUEST = 18;
+  } else if(peer->getLatency() < 1000) {
+    MAX_PENDING_REQUEST = 12;
+  } else {
+    MAX_PENDING_REQUEST = 6;
+  }
+  int pieceNum;
+  if(torrentMan->isEndGame()) {
+    pieceNum = 1;
+  } else {
+    int blocks = DIV_FLOOR(torrentMan->pieceLength, BLOCK_LENGTH);
+    pieceNum = DIV_FLOOR(MAX_PENDING_REQUEST, blocks);
+  }
+  getNewPieceAndSendInterest(pieceNum);
+  for(Pieces::iterator itr = pieces.begin(); itr != pieces.end(); itr++) {
+    Piece& piece = *itr;
     if(torrentMan->isEndGame()) {
       BlockIndexes missingBlockIndexes = piece.getAllMissingBlockIndexes();
-      if(countRequestSlot() == 0) {
-	random_shuffle(missingBlockIndexes.begin(), missingBlockIndexes.end());
-	int count = 0;
-	for(BlockIndexes::const_iterator itr = missingBlockIndexes.begin();
-	    itr != missingBlockIndexes.end() && count < 6; itr++, count++) {
-	  addMessage(createRequestMessage(*itr));
+      random_shuffle(missingBlockIndexes.begin(), missingBlockIndexes.end());
+      int count = countRequestSlot();
+      for(BlockIndexes::const_iterator bitr = missingBlockIndexes.begin();
+	  bitr != missingBlockIndexes.end() && count < MAX_PENDING_REQUEST;
+	  bitr++) {
+	int blockIndex = *bitr;
+	if(!isInRequestSlot(piece.getIndex(), blockIndex)) {
+	  addMessage(createRequestMessage(piece.getIndex(), blockIndex));
+	  count++;
 	}
       }
     } else {
-      for(int i = countRequestSlot(); i < 6; i++) {
+      while(countRequestSlot() < MAX_PENDING_REQUEST) {
 	int blockIndex = piece.getMissingUnusedBlockIndex();
 	if(blockIndex == -1) {
 	  break;
 	}
-	torrentMan->updatePiece(piece);
-	addMessage(createRequestMessage(blockIndex));
+	addMessage(createRequestMessage(piece.getIndex(), blockIndex));
       }
     }
+    if(countRequestSlot() >= MAX_PENDING_REQUEST) {
+      break;
+    }
   }
+  updatePiece();
 }
 
 void PeerInteraction::sendHandshake() {
@@ -474,11 +555,22 @@ void PeerInteraction::sendAllowedFast() {
   }
 }
 
-Piece& PeerInteraction::getDownloadPiece() {
-  if(Piece::isNull(piece)) {
-    throw new DlAbortEx("current piece is null");
+Piece& PeerInteraction::getDownloadPiece(int index) {
+  for(Pieces::iterator itr = pieces.begin(); itr != pieces.end(); itr++) {
+    if(itr->getIndex() == index) {
+      return *itr;
+    }
   }
-  return piece;
+  throw new DlAbortEx("No such piece index=%d", index);
+}
+
+bool PeerInteraction::hasDownloadPiece(int index) const {
+  for(Pieces::const_iterator itr = pieces.begin(); itr != pieces.end(); itr++) {
+    if(itr->getIndex() == index) {
+      return true;
+    }
+  }
+  return false;
 }
 
 bool PeerInteraction::isInFastSet(int index) const {
@@ -497,8 +589,9 @@ void PeerInteraction::setPeerMessageCommonProperty(PeerMessage* peerMessage) {
   peerMessage->setPeerInteraction(this);  
 }
 
-RequestMessage* PeerInteraction::createRequestMessage(int blockIndex) {
+RequestMessage* PeerInteraction::createRequestMessage(int index, int blockIndex) {
   RequestMessage* msg = new RequestMessage();
+  Piece piece = getDownloadPiece(index);
   msg->setIndex(piece.getIndex());
   msg->setBegin(blockIndex*piece.getBlockLength());
   msg->setLength(piece.getBlockLength(blockIndex));
diff --git a/src/PeerInteraction.h b/src/PeerInteraction.h
index f41c6bce..079a4973 100644
--- a/src/PeerInteraction.h
+++ b/src/PeerInteraction.h
@@ -48,6 +48,7 @@
 
 typedef deque<RequestSlot> RequestSlots;
 typedef deque<PeerMessage*> MessageQueue;
+typedef deque<Piece> Pieces;
 
 class PeerInteraction {
 private:
@@ -59,12 +60,12 @@ private:
   TorrentMan* torrentMan;
   PeerConnection* peerConnection;
   Peer* peer;
-  Piece piece;
+  Pieces pieces;
   // allowed fast piece indexes that local client has sent
   Integers fastSet;
   const Logger* logger;
   
-  void getNewPieceAndSendInterest();
+  void getNewPieceAndSendInterest(int pieceNum);
   PeerMessage* createPeerMessage(const char* msg, int msgLength);
   HandshakeMessage* createHandshakeMessage(const char* msg, int msgLength);
   void setPeerMessageCommonProperty(PeerMessage* peerMessage);
@@ -81,13 +82,15 @@ public:
   void rejectPieceMessageInQueue(int index, int begin, int length);
   void rejectAllPieceMessageInQueue();
   void onChoked();
-  void abortPiece();
+  void abortPiece(Piece& piece);
+  void abortAllPieces();
 
   bool isSendingMessageInProgress() const;
   void deleteRequestSlot(const RequestSlot& requestSlot);
   void deleteTimeoutRequestSlot();
   void deleteCompletedRequestSlot();
   RequestSlot getCorrespondingRequestSlot(int index, int begin, int length) const;
+  bool isInRequestSlot(int index, int blockIndex) const;
 
   int countMessageInQueue() const;
 
@@ -97,21 +100,17 @@ public:
   TorrentMan* getTorrentMan() const { return torrentMan; }
   PeerConnection* getPeerConnection() const { return peerConnection; }
   // If this object has nullPiece, then return false, otherwise true
-  bool hasDownloadPiece() const {
-    return !Piece::isNull(piece);
-  }
+  bool hasDownloadPiece(int index) const;
   // If the piece which this object has is nullPiece, then throws an exception.
   // So before calling this function, call hasDownloadPiece and make sure
   // this has valid piece, not nullPiece.
-  Piece& getDownloadPiece();
-  void setDownloadPiece(const Piece& piece) {
-    this->piece = piece;
-  }
+  Piece& getDownloadPiece(int index);
   
   bool isInFastSet(int index) const;
   void addFastSetIndex(int index);
 
   void syncPiece();
+  void updatePiece();
   void addRequests();
   void sendMessages(int currentUploadSpeed);
   void sendHandshake();
@@ -121,7 +120,7 @@ public:
   PeerMessage* receiveMessage();
   HandshakeMessage* receiveHandshake();
 
-  RequestMessage* createRequestMessage(int blockIndex);
+  RequestMessage* createRequestMessage(int index, int blockIndex);
   CancelMessage* createCancelMessage(int index, int begin, int length);
   PieceMessage* createPieceMessage(int index, int begin, int length);
   HaveMessage* createHaveMessage(int index);
diff --git a/src/PeerInteractionCommand.cc b/src/PeerInteractionCommand.cc
index 16e32515..e7be9d55 100644
--- a/src/PeerInteractionCommand.cc
+++ b/src/PeerInteractionCommand.cc
@@ -113,7 +113,7 @@ bool PeerInteractionCommand::executeInternal() {
   case WIRED:
     peerInteraction->syncPiece();
     decideChoking();
-    for(int i = 0; i < 10; i++) {
+    for(int i = 0; i < 50; i++) {
       if(!socket->isReadable(0)) {
 	break;
       }
@@ -245,7 +245,7 @@ bool PeerInteractionCommand::prepareForRetry(int wait) {
 }
 
 void PeerInteractionCommand::onAbort(Exception* ex) {
-  peerInteraction->abortPiece();
+  peerInteraction->abortAllPieces();
   PeerAbstractCommand::onAbort(ex);
 }
 
diff --git a/src/Piece.cc b/src/Piece.cc
index d4a36972..0c183d34 100644
--- a/src/Piece.cc
+++ b/src/Piece.cc
@@ -49,6 +49,10 @@ Piece& Piece::operator=(const Piece& piece) {
   return *this;
 }
 
+bool Piece::operator==(const Piece& piece) const {
+  return index == piece.index;
+}
+
 void Piece::completeBlock(int blockIndex) {
   bitfield->setBit(blockIndex);
   bitfield->unsetUseBit(blockIndex);
@@ -79,6 +83,15 @@ int Piece::getMissingUnusedBlockIndex() const {
   return blockIndex;
 }
 
+int Piece::getMissingBlockIndex() const {
+  int blockIndex = bitfield->getMissingIndex();
+  if(blockIndex == -1) {
+    return blockIndex;
+  }
+  bitfield->setUseBit(blockIndex);
+  return blockIndex;
+}
+
 BlockIndexes Piece::getAllMissingBlockIndexes() const {
   return bitfield->getAllMissingIndexes();
 }
diff --git a/src/Piece.h b/src/Piece.h
index 9d77576f..7cf322ce 100644
--- a/src/Piece.h
+++ b/src/Piece.h
@@ -43,8 +43,10 @@ public:
   }
 
   Piece& operator=(const Piece& piece);
+  bool operator==(const Piece& piece) const;
 
   int getMissingUnusedBlockIndex() const;
+  int getMissingBlockIndex() const;
   BlockIndexes getAllMissingBlockIndexes() const;
   void completeBlock(int blockIndex);
   void cancelBlock(int blockIndex);
diff --git a/src/PieceMessage.cc b/src/PieceMessage.cc
index 54de5851..4930204b 100644
--- a/src/PieceMessage.cc
+++ b/src/PieceMessage.cc
@@ -57,9 +57,11 @@ void PieceMessage::receivedAction() {
 								  begin,
 								  blockLength);
   peer->addPeerUpload(blockLength);
-  if(peerInteraction->hasDownloadPiece() &&
-     !RequestSlot::isNull(slot)) {
-    Piece& piece = peerInteraction->getDownloadPiece();
+  if(!RequestSlot::isNull(slot) &&
+     peerInteraction->hasDownloadPiece(slot.getIndex())) {
+    //logger->debug("CUID#%d - Latency=%d", cuid, slot.getLatencyInMillis());
+    peer->updateLatency(slot.getLatencyInMillis());
+    Piece& piece = peerInteraction->getDownloadPiece(slot.getIndex());
     long long int offset =
       ((long long int)index)*torrentMan->pieceLength+begin;
     logger->debug("CUID#%d - Writing the block length=%d, offset=%lld",
@@ -197,7 +199,6 @@ void PieceMessage::onGotNewPiece(Piece& piece) {
   logger->info(MSG_GOT_NEW_PIECE, cuid, piece.getIndex());
   torrentMan->completePiece(piece);
   torrentMan->advertisePiece(cuid, piece.getIndex());
-  piece = Piece::nullPiece;
 }
 
 void PieceMessage::onGotWrongPiece(Piece& piece) {
diff --git a/src/RequestSlot.cc b/src/RequestSlot.cc
index 7793999e..3cdd7957 100644
--- a/src/RequestSlot.cc
+++ b/src/RequestSlot.cc
@@ -53,9 +53,13 @@ void RequestSlot::setDispatchedTime() {
 }
 
 bool RequestSlot::isTimeout(int timeoutSec) const {
+  return getLatencyInMillis() > timeoutSec*1000;
+}
+
+int RequestSlot::getLatencyInMillis() const {
   struct timeval now;
   gettimeofday(&now, NULL);
-  return Util::difftv(now, dispatchedTime) > ((long long int)timeoutSec)*1000000;
+  return Util::difftv(now, dispatchedTime)/1000;
 }
 
 bool RequestSlot::isNull(const RequestSlot& requestSlot) {
diff --git a/src/RequestSlot.h b/src/RequestSlot.h
index f4c36d9b..a7e565ea 100644
--- a/src/RequestSlot.h
+++ b/src/RequestSlot.h
@@ -43,6 +43,7 @@ public:
   void setDispatchedTime();
 
   bool isTimeout(int timeoutSec) const;
+  int getLatencyInMillis() const;
 
   bool operator==(const RequestSlot& requestSlot) const;
 
diff --git a/src/TorrentMan.cc b/src/TorrentMan.cc
index 0cad6e26..c8b1b394 100644
--- a/src/TorrentMan.cc
+++ b/src/TorrentMan.cc
@@ -145,7 +145,19 @@ bool TorrentMan::isEndGame() const {
   return bitfield->countMissingBlock() <= END_GAME_PIECE_NUM;
 }
 
-Piece TorrentMan::getMissingPiece(const Peer* peer) {
+int TorrentMan::getMissingPieceIndex(const Peer* peer) const {
+  int index = -1;
+  if(isEndGame()) {
+    index = bitfield->getMissingIndex(peer->getBitfield(),
+				      peer->getBitfieldLength());
+  } else {
+    index = bitfield->getMissingUnusedIndex(peer->getBitfield(),
+					    peer->getBitfieldLength());
+  }
+  return index;
+}
+
+int TorrentMan::getMissingFastPieceIndex(const Peer* peer) const {
   int index = -1;
   if(peer->isFastExtensionEnabled() && peer->countFastSet() > 0) {
     BitfieldMan tempBitfield(pieceLength, totalLength);
@@ -163,15 +175,20 @@ Piece TorrentMan::getMissingPiece(const Peer* peer) {
 					      tempBitfield.getBitfieldLength());
     }
   }
-  if(index == -1) {
-    if(isEndGame()) {
-      index = bitfield->getMissingIndex(peer->getBitfield(),
-					peer->getBitfieldLength());
-    } else {
-      index = bitfield->getMissingUnusedIndex(peer->getBitfield(),
-					      peer->getBitfieldLength());
-    }
-  }
+  return index;
+}
+
+Piece TorrentMan::getMissingFastPiece(const Peer* peer) {
+  int index = getMissingFastPieceIndex(peer);
+  return checkOutPiece(index);
+}
+
+Piece TorrentMan::getMissingPiece(const Peer* peer) {
+  int index = getMissingPieceIndex(peer);
+  return checkOutPiece(index);
+}
+
+Piece TorrentMan::checkOutPiece(int index) {
   if(index == -1) {
     return Piece::nullPiece;
   }
@@ -281,11 +298,10 @@ void TorrentMan::updatePiece(const Piece& piece) {
   if(Piece::isNull(piece)) {
     return;
   }
-  for(UsedPieces::iterator itr = usedPieces.begin(); itr != usedPieces.end(); itr++) {
-    if(itr->getIndex() == piece.getIndex()) {
-      *itr = piece;
-      break;
-    }
+  UsedPieces::iterator itr = find(usedPieces.begin(), usedPieces.end(),
+				  piece);
+  if(itr != usedPieces.end()) {
+    *itr = piece;
   }
 }
 
@@ -293,17 +309,18 @@ void TorrentMan::syncPiece(Piece& piece) {
   if(Piece::isNull(piece)) {
     return;
   }
-  for(UsedPieces::iterator itr = usedPieces.begin(); itr != usedPieces.end(); itr++) {
-    if(itr->getIndex() == piece.getIndex()) {
-      piece = *itr;
-      return;
+  UsedPieces::iterator itr = find(usedPieces.begin(), usedPieces.end(),
+				  piece);
+  if(itr != usedPieces.end()) {
+    piece = *itr;
+    return;
+  } else {
+    // hasPiece(piece.getIndex()) is true, then set all bit of
+    // piece.bitfield to 1
+    if(hasPiece(piece.getIndex())) {
+      piece.setAllBlock();
     }
   }
-  // hasPiece(piece.getIndex()) is true, then set all bit of
-  // piece.bitfield to 1
-  if(hasPiece(piece.getIndex())) {
-    piece.setAllBlock();
-  }
 }
 
 void TorrentMan::initBitfield() {
diff --git a/src/TorrentMan.h b/src/TorrentMan.h
index 2a84a45c..8fbdba6a 100644
--- a/src/TorrentMan.h
+++ b/src/TorrentMan.h
@@ -91,6 +91,7 @@ private:
   void setFileFilter(const Strings& filePaths);
   void setupInternal1(const string& metaInfoFile);
   void setupInternal2();
+  Piece checkOutPiece(int index);
 public:
   int pieceLength;
   int pieces;
@@ -126,7 +127,10 @@ public:
   bool isPeerAvailable() const;
   int deleteOldErrorPeers(int maxNum);
 
+  int getMissingPieceIndex(const Peer* peer) const;
+  int getMissingFastPieceIndex(const Peer* peer) const;
   Piece getMissingPiece(const Peer* peer);
+  Piece getMissingFastPiece(const Peer* peer);
   void completePiece(const Piece& piece);
   void cancelPiece(const Piece& piece);
   void updatePiece(const Piece& piece);
diff --git a/src/common.h b/src/common.h
index 298f136e..81889b82 100644
--- a/src/common.h
+++ b/src/common.h
@@ -44,7 +44,9 @@
 
 #define USER_AGENT "aria2"
 
-#define BITFIELD_LEN_FROM_PIECES(X) (X/8+(X%8? 1 : 0))
+#define BITFIELD_LEN_FROM_PIECES(X) ((X)/8+((X)%8? 1 : 0))
+
+#define DIV_FLOOR(X,Y) ((X)/(Y)+((X)%(Y)? 1:0))
 
 using namespace std;