m_round_robin_start = 0;
     m_network_ptr = network_ptr;
     m_wakeups_wo_switch = 0;
+
+    for(int i = 0;i < m_virtual_networks;++i)
+    {
+        m_pending_message_count.push_back(0);
+    }
 }
 
 void
     assert(in.size() == m_virtual_networks);
     NodeID port = m_in.size();
     m_in.push_back(in);
+
     for (int j = 0; j < m_virtual_networks; j++) {
         m_in[port][j]->setConsumer(this);
         string desc = csprintf("[Queue from port %s %s %s to PerfectSwitch]",
             NodeIDToString(m_switch_id), NodeIDToString(port),
             NodeIDToString(j));
         m_in[port][j]->setDescription(desc);
+        m_in[port][j]->setIncomingLink(port);
+        m_in[port][j]->setVnet(j);
     }
 }
 
             m_round_robin_start = 0;
         }
 
-        // for all input ports, use round robin scheduling
-        for (int counter = 0; counter < m_in.size(); counter++) {
-            // Round robin scheduling
-            incoming++;
-            if (incoming >= m_in.size()) {
-                incoming = 0;
-            }
+        if(m_pending_message_count[vnet] > 0) {
+            // for all input ports, use round robin scheduling
+            for (int counter = 0; counter < m_in.size(); counter++) {
+                // Round robin scheduling
+                incoming++;
+                if (incoming >= m_in.size()) {
+                    incoming = 0;
+                }
 
-            // temporary vectors to store the routing results
-            vector<LinkID> output_links;
-            vector<NetDest> output_link_destinations;
-
-            // Is there a message waiting?
-            while (m_in[incoming][vnet]->isReady()) {
-                DPRINTF(RubyNetwork, "incoming: %d\n", incoming);
-
-                // Peek at message
-                msg_ptr = m_in[incoming][vnet]->peekMsgPtr();
-                net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
-                DPRINTF(RubyNetwork, "Message: %s\n", (*net_msg_ptr));
-
-                output_links.clear();
-                output_link_destinations.clear();
-                NetDest msg_dsts =
-                    net_msg_ptr->getInternalDestination();
-
-                // Unfortunately, the token-protocol sends some
-                // zero-destination messages, so this assert isn't valid
-                // assert(msg_dsts.count() > 0);
-
-                assert(m_link_order.size() == m_routing_table.size());
-                assert(m_link_order.size() == m_out.size());
-
-                if (m_network_ptr->getAdaptiveRouting()) {
-                    if (m_network_ptr->isVNetOrdered(vnet)) {
-                        // Don't adaptively route
-                        for (int out = 0; out < m_out.size(); out++) {
-                            m_link_order[out].m_link = out;
-                            m_link_order[out].m_value = 0;
-                        }
-                    } else {
-                        // Find how clogged each link is
-                        for (int out = 0; out < m_out.size(); out++) {
-                            int out_queue_length = 0;
-                            for (int v = 0; v < m_virtual_networks; v++) {
-                                out_queue_length += m_out[out][v]->getSize();
+                // temporary vectors to store the routing results
+                vector<LinkID> output_links;
+                vector<NetDest> output_link_destinations;
+
+                // Is there a message waiting?
+                while (m_in[incoming][vnet]->isReady()) {
+                    DPRINTF(RubyNetwork, "incoming: %d\n", incoming);
+
+                    // Peek at message
+                    msg_ptr = m_in[incoming][vnet]->peekMsgPtr();
+                    net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
+                    DPRINTF(RubyNetwork, "Message: %s\n", (*net_msg_ptr));
+
+                    output_links.clear();
+                    output_link_destinations.clear();
+                    NetDest msg_dsts =
+                        net_msg_ptr->getInternalDestination();
+
+                    // Unfortunately, the token-protocol sends some
+                    // zero-destination messages, so this assert isn't valid
+                    // assert(msg_dsts.count() > 0);
+
+                    assert(m_link_order.size() == m_routing_table.size());
+                    assert(m_link_order.size() == m_out.size());
+
+                    if (m_network_ptr->getAdaptiveRouting()) {
+                        if (m_network_ptr->isVNetOrdered(vnet)) {
+                            // Don't adaptively route
+                            for (int out = 0; out < m_out.size(); out++) {
+                                m_link_order[out].m_link = out;
+                                m_link_order[out].m_value = 0;
+                            }
+                        } else {
+                            // Find how clogged each link is
+                            for (int out = 0; out < m_out.size(); out++) {
+                                int out_queue_length = 0;
+                                for (int v = 0; v < m_virtual_networks; v++) {
+                                    out_queue_length += m_out[out][v]->getSize();
+                                }
+                                int value =
+                                    (out_queue_length << 8) | (random() & 0xff);
+                                m_link_order[out].m_link = out;
+                                m_link_order[out].m_value = value;
                             }
-                            int value =
-                                (out_queue_length << 8) | (random() & 0xff);
-                            m_link_order[out].m_link = out;
-                            m_link_order[out].m_value = value;
+
+                            // Look at the most empty link first
+                            sort(m_link_order.begin(), m_link_order.end());
                         }
+                    }
 
-                        // Look at the most empty link first
-                        sort(m_link_order.begin(), m_link_order.end());
+                    for (int i = 0; i < m_routing_table.size(); i++) {
+                        // pick the next link to look at
+                        int link = m_link_order[i].m_link;
+                        NetDest dst = m_routing_table[link];
+                        DPRINTF(RubyNetwork, "dst: %s\n", dst);
+
+                        if (!msg_dsts.intersectionIsNotEmpty(dst))
+                            continue;
+
+                        // Remember what link we're using
+                        output_links.push_back(link);
+
+                        // Need to remember which destinations need this
+                        // message in another vector.  This Set is the
+                        // intersection of the routing_table entry and the
+                        // current destination set.  The intersection must
+                        // not be empty, since we are inside "if"
+                        output_link_destinations.push_back(msg_dsts.AND(dst));
+
+                        // Next, we update the msg_destination not to
+                        // include those nodes that were already handled
+                        // by this link
+                        msg_dsts.removeNetDest(dst);
                     }
-                }
 
-                for (int i = 0; i < m_routing_table.size(); i++) {
-                    // pick the next link to look at
-                    int link = m_link_order[i].m_link;
-                    NetDest dst = m_routing_table[link];
-                    DPRINTF(RubyNetwork, "dst: %s\n", dst);
-
-                    if (!msg_dsts.intersectionIsNotEmpty(dst))
-                        continue;
-
-                    // Remember what link we're using
-                    output_links.push_back(link);
-
-                    // Need to remember which destinations need this
-                    // message in another vector.  This Set is the
-                    // intersection of the routing_table entry and the
-                    // current destination set.  The intersection must
-                    // not be empty, since we are inside "if"
-                    output_link_destinations.push_back(msg_dsts.AND(dst));
-
-                    // Next, we update the msg_destination not to
-                    // include those nodes that were already handled
-                    // by this link
-                    msg_dsts.removeNetDest(dst);
-                }
+                    assert(msg_dsts.count() == 0);
+                    //assert(output_links.size() > 0);
+
+                    // Check for resources - for all outgoing queues
+                    bool enough = true;
+                    for (int i = 0; i < output_links.size(); i++) {
+                        int outgoing = output_links[i];
+                        if (!m_out[outgoing][vnet]->areNSlotsAvailable(1))
+                            enough = false;
+                        DPRINTF(RubyNetwork, "Checking if node is blocked\n"
+                                "outgoing: %d, vnet: %d, enough: %d\n",
+                                outgoing, vnet, enough);
+                    }
 
-                assert(msg_dsts.count() == 0);
-                //assert(output_links.size() > 0);
-
-                // Check for resources - for all outgoing queues
-                bool enough = true;
-                for (int i = 0; i < output_links.size(); i++) {
-                    int outgoing = output_links[i];
-                    if (!m_out[outgoing][vnet]->areNSlotsAvailable(1))
-                        enough = false;
-                    DPRINTF(RubyNetwork, "Checking if node is blocked\n"
-                            "outgoing: %d, vnet: %d, enough: %d\n",
-                            outgoing, vnet, enough);
-                }
+                    // There were not enough resources
+                    if (!enough) {
+                        g_eventQueue_ptr->scheduleEvent(this, 1);
+                        DPRINTF(RubyNetwork, "Can't deliver message since a node "
+                                "is blocked\n"
+                                "Message: %s\n", (*net_msg_ptr));
+                        break; // go to next incoming port
+                    }
 
-                // There were not enough resources
-                if (!enough) {
-                    g_eventQueue_ptr->scheduleEvent(this, 1);
-                    DPRINTF(RubyNetwork, "Can't deliver message since a node "
-                            "is blocked\n"
-                            "Message: %s\n", (*net_msg_ptr));
-                    break; // go to next incoming port
-                }
+                    MsgPtr unmodified_msg_ptr;
 
-                MsgPtr unmodified_msg_ptr;
+                    if (output_links.size() > 1) {
+                        // If we are sending this message down more than
+                        // one link (size>1), we need to make a copy of
+                        // the message so each branch can have a different
+                        // internal destination we need to create an
+                        // unmodified MsgPtr because the MessageBuffer
+                        // enqueue func will modify the message
 
-                if (output_links.size() > 1) {
-                    // If we are sending this message down more than
-                    // one link (size>1), we need to make a copy of
-                    // the message so each branch can have a different
-                    // internal destination we need to create an
-                    // unmodified MsgPtr because the MessageBuffer
-                    // enqueue func will modify the message
+                        // This magic line creates a private copy of the
+                        // message
+                        unmodified_msg_ptr = msg_ptr->clone();
+                    }
 
-                    // This magic line creates a private copy of the
-                    // message
-                    unmodified_msg_ptr = msg_ptr->clone();
-                }
+                    // Enqueue it - for all outgoing queues
+                    for (int i=0; i<output_links.size(); i++) {
+                        int outgoing = output_links[i];
 
-                // Enqueue it - for all outgoing queues
-                for (int i=0; i<output_links.size(); i++) {
-                    int outgoing = output_links[i];
+                        if (i > 0) {
+                            // create a private copy of the unmodified
+                            // message
+                            msg_ptr = unmodified_msg_ptr->clone();
+                        }
 
-                    if (i > 0) {
-                        // create a private copy of the unmodified
-                        // message
-                        msg_ptr = unmodified_msg_ptr->clone();
-                    }
+                        // Change the internal destination set of the
+                        // message so it knows which destinations this
+                        // link is responsible for.
+                        net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
+                        net_msg_ptr->getInternalDestination() =
+                            output_link_destinations[i];
 
-                    // Change the internal destination set of the
-                    // message so it knows which destinations this
-                    // link is responsible for.
-                    net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
-                    net_msg_ptr->getInternalDestination() =
-                        output_link_destinations[i];
+                        // Enqeue msg
+                        DPRINTF(RubyNetwork, "Switch: %d enqueuing net msg from "
+                                "inport[%d][%d] to outport [%d][%d] time: %lld.\n",
+                                m_switch_id, incoming, vnet, outgoing, vnet,
+                                g_eventQueue_ptr->getTime());
 
-                    // Enqeue msg
-                    DPRINTF(RubyNetwork, "Switch: %d enqueuing net msg from "
-                            "inport[%d][%d] to outport [%d][%d] time: %lld.\n",
-                            m_switch_id, incoming, vnet, outgoing, vnet,
-                            g_eventQueue_ptr->getTime());
+                        m_out[outgoing][vnet]->enqueue(msg_ptr);
+                    }
 
-                    m_out[outgoing][vnet]->enqueue(msg_ptr);
+                    // Dequeue msg
+                    m_in[incoming][vnet]->pop();
+                    m_pending_message_count[vnet]--;
                 }
-
-                // Dequeue msg
-                m_in[incoming][vnet]->pop();
             }
         }
     }
 }
 
+void
+PerfectSwitch::storeEventInfo(int info)
+{
+    m_pending_message_count[info]++;
+}
+
 void
 PerfectSwitch::printStats(std::ostream& out) const
 {