src/mem/ruby/buffers/MessageBuffer.cc - arm/gem5 - Git at Google

 /*
  * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met: redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer;
  * redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution;
  * neither the name of the copyright holders nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include <cassert>

 #include "base/cprintf.hh"
 #include "base/misc.hh"
 #include "base/stl_helpers.hh"
 #include "debug/RubyQueue.hh"
 #include "mem/ruby/buffers/MessageBuffer.hh"
 #include "mem/ruby/system/System.hh"

 using namespace std;
 using m5::stl_helpers::operator<<;

 MessageBuffer::MessageBuffer(const string &name)
 {
     m_msg_counter = 0;
     m_consumer_ptr = NULL;
     m_ordering_set = false;
     m_strict_fifo = true;
     m_size = 0;
     m_max_size = -1;
     m_last_arrival_time = 0;
     m_randomization = true;
     m_size_last_time_size_checked = 0;
     m_time_last_time_size_checked = 0;
     m_time_last_time_enqueue = 0;
     m_time_last_time_pop = 0;
     m_size_at_cycle_start = 0;
     m_msgs_this_cycle = 0;
     m_not_avail_count = 0;
     m_priority_rank = 0;
     m_name = name;

     m_stall_msg_map.clear();
     m_input_link_id = 0;
     m_vnet_id = 0;
 }

 int
 MessageBuffer::getSize()
 {
     if (m_time_last_time_size_checked == g_eventQueue_ptr->getTime()) {
         return m_size_last_time_size_checked;
     } else {
         m_time_last_time_size_checked = g_eventQueue_ptr->getTime();
         m_size_last_time_size_checked = m_size;
         return m_size;
     }
 }

 bool
 MessageBuffer::areNSlotsAvailable(int n)
 {

     // fast path when message buffers have infinite size
     if (m_max_size == -1) {
         return true;
     }

     // determine my correct size for the current cycle
     // pop operations shouldn't effect the network's visible size
     // until next cycle, but enqueue operations effect the visible
     // size immediately
     int current_size = max(m_size_at_cycle_start, m_size);
     if (m_time_last_time_pop < g_eventQueue_ptr->getTime()) {
         // no pops this cycle - m_size is correct
         current_size = m_size;
     } else {
         if (m_time_last_time_enqueue < g_eventQueue_ptr->getTime()) {
             // no enqueues this cycle - m_size_at_cycle_start is correct
             current_size = m_size_at_cycle_start;
         } else {
             // both pops and enqueues occured this cycle - add new
             // enqueued msgs to m_size_at_cycle_start
             current_size = m_size_at_cycle_start+m_msgs_this_cycle;
         }
     }

     // now compare the new size with our max size
     if (current_size + n <= m_max_size) {
         return true;
     } else {
         DPRINTF(RubyQueue, "n: %d, current_size: %d, m_size: %d, "
                 "m_max_size: %d\n",
                 n, current_size, m_size, m_max_size);
         m_not_avail_count++;
         return false;
     }
 }

 const MsgPtr
 MessageBuffer::getMsgPtrCopy() const
 {
     assert(isReady());

     return m_prio_heap.front().m_msgptr->clone();
 }

 const Message*
 MessageBuffer::peekAtHeadOfQueue() const
 {
     DPRINTF(RubyQueue, "Peeking at head of queue.\n");
     assert(isReady());

     const Message* msg_ptr = m_prio_heap.front().m_msgptr.get();
     assert(msg_ptr);

     DPRINTF(RubyQueue, "Message: %s\n", (*msg_ptr));
     return msg_ptr;
 }

 // FIXME - move me somewhere else
 int
 random_time()
 {
     int time = 1;
     time += random() & 0x3;  // [0...3]
     if ((random() & 0x7) == 0) {  // 1 in 8 chance
         time += 100 + (random() % 0xf); // 100 + [1...15]
     }
     return time;
 }

 void
 MessageBuffer::enqueue(MsgPtr message, Time delta)
 {
     m_msg_counter++;
     m_size++;

     // record current time incase we have a pop that also adjusts my size
     if (m_time_last_time_enqueue < g_eventQueue_ptr->getTime()) {
         m_msgs_this_cycle = 0;  // first msg this cycle
         m_time_last_time_enqueue = g_eventQueue_ptr->getTime();
     }
     m_msgs_this_cycle++;

     if (!m_ordering_set) {
         panic("Ordering property of %s has not been set", m_name);
     }

     // Calculate the arrival time of the message, that is, the first
     // cycle the message can be dequeued.
     assert(delta>0);
     Time current_time = g_eventQueue_ptr->getTime();
     Time arrival_time = 0;
     if (!RubySystem::getRandomization() || (m_randomization == false)) {
         // No randomization
         arrival_time = current_time + delta;
     } else {
         // Randomization - ignore delta
         if (m_strict_fifo) {
             if (m_last_arrival_time < current_time) {
                 m_last_arrival_time = current_time;
             }
             arrival_time = m_last_arrival_time + random_time();
         } else {
             arrival_time = current_time + random_time();
         }
     }

     // Check the arrival time
     assert(arrival_time > current_time);
     if (m_strict_fifo) {
         if (arrival_time < m_last_arrival_time) {
             panic("FIFO ordering violated: %s name: %s current time: %d "
                   "delta: %d arrival_time: %d last arrival_time: %d\n",
                   *this, m_name,
                   current_time * g_eventQueue_ptr->getClock(),
                   delta * g_eventQueue_ptr->getClock(),
                   arrival_time * g_eventQueue_ptr->getClock(),
                   m_last_arrival_time * g_eventQueue_ptr->getClock());
         }
     }

     // If running a cache trace, don't worry about the last arrival checks
     if (!g_system_ptr->m_warmup_enabled) {
         m_last_arrival_time = arrival_time;
     }

     // compute the delay cycles and set enqueue time
     Message* msg_ptr = message.get();
     assert(msg_ptr != NULL);

     assert(g_eventQueue_ptr->getTime() >= msg_ptr->getLastEnqueueTime() &&
            "ensure we aren't dequeued early");

     msg_ptr->setDelayedCycles(g_eventQueue_ptr->getTime() -
                               msg_ptr->getLastEnqueueTime() +
                               msg_ptr->getDelayedCycles());
     msg_ptr->setLastEnqueueTime(arrival_time);

     // Insert the message into the priority heap
     MessageBufferNode thisNode(arrival_time, m_msg_counter, message);
     m_prio_heap.push_back(thisNode);
     push_heap(m_prio_heap.begin(), m_prio_heap.end(),
         greater<MessageBufferNode>());

     DPRINTF(RubyQueue, "Enqueue with arrival_time %lld.\n",
             arrival_time * g_eventQueue_ptr->getClock());
     DPRINTF(RubyQueue, "Enqueue Message: %s.\n", (*(message.get())));

     // Schedule the wakeup
     if (m_consumer_ptr != NULL) {
         g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, arrival_time);
         m_consumer_ptr->storeEventInfo(m_vnet_id);
     } else {
         panic("No consumer: %s name: %s\n", *this, m_name);
     }
 }

 int
 MessageBuffer::dequeue_getDelayCycles(MsgPtr& message)
 {
     int delay_cycles = -1;  // null value

     dequeue(message);

     // get the delay cycles
     delay_cycles = setAndReturnDelayCycles(message);

     assert(delay_cycles >= 0);
     return delay_cycles;
 }

 void
 MessageBuffer::dequeue(MsgPtr& message)
 {
     DPRINTF(RubyQueue, "Dequeueing\n");
     message = m_prio_heap.front().m_msgptr;

     pop();
     DPRINTF(RubyQueue, "Enqueue message is %s\n", (*(message.get())));
 }

 int
 MessageBuffer::dequeue_getDelayCycles()
 {
     int delay_cycles = -1;  // null value

     // get MsgPtr of the message about to be dequeued
     MsgPtr message = m_prio_heap.front().m_msgptr;

     // get the delay cycles
     delay_cycles = setAndReturnDelayCycles(message);

     dequeue();

     assert(delay_cycles >= 0);
     return delay_cycles;
 }

 void
 MessageBuffer::pop()
 {
     DPRINTF(RubyQueue, "Popping\n");
     assert(isReady());
     pop_heap(m_prio_heap.begin(), m_prio_heap.end(),
         greater<MessageBufferNode>());
     m_prio_heap.pop_back();

     // record previous size and time so the current buffer size isn't
     // adjusted until next cycle
     if (m_time_last_time_pop < g_eventQueue_ptr->getTime()) {
         m_size_at_cycle_start = m_size;
         m_time_last_time_pop = g_eventQueue_ptr->getTime();
     }
     m_size--;
 }

 void
 MessageBuffer::clear()
 {
     m_prio_heap.clear();

     m_msg_counter = 0;
     m_size = 0;
     m_time_last_time_enqueue = 0;
     m_time_last_time_pop = 0;
     m_size_at_cycle_start = 0;
     m_msgs_this_cycle = 0;
 }

 void
 MessageBuffer::recycle()
 {
     DPRINTF(RubyQueue, "Recycling.\n");
     assert(isReady());
     MessageBufferNode node = m_prio_heap.front();
     pop_heap(m_prio_heap.begin(), m_prio_heap.end(),
         greater<MessageBufferNode>());
     node.m_time = g_eventQueue_ptr->getTime() + m_recycle_latency;
     m_prio_heap.back() = node;
     push_heap(m_prio_heap.begin(), m_prio_heap.end(),
         greater<MessageBufferNode>());
     g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr,
         g_eventQueue_ptr->getTime() + m_recycle_latency);
 }

 void
 MessageBuffer::reanalyzeMessages(const Address& addr)
 {
     DPRINTF(RubyQueue, "ReanalyzeMessages\n");
     assert(m_stall_msg_map.count(addr) > 0);

     //
     // Put all stalled messages associated with this address back on the
     // prio heap
     //
     while(!m_stall_msg_map[addr].empty()) {
         m_msg_counter++;
         MessageBufferNode msgNode(g_eventQueue_ptr->getTime() + 1,
                                   m_msg_counter,
                                   m_stall_msg_map[addr].front());

         m_prio_heap.push_back(msgNode);
         push_heap(m_prio_heap.begin(), m_prio_heap.end(),
                   greater<MessageBufferNode>());

         g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, msgNode.m_time);
         m_stall_msg_map[addr].pop_front();
     }
     m_stall_msg_map.erase(addr);
 }

 void
 MessageBuffer::reanalyzeAllMessages()
 {
     DPRINTF(RubyQueue, "ReanalyzeAllMessages %s\n");

     //
     // Put all stalled messages associated with this address back on the
     // prio heap
     //
     for (StallMsgMapType::iterator map_iter = m_stall_msg_map.begin();
          map_iter != m_stall_msg_map.end();
          ++map_iter) {

         while(!(map_iter->second).empty()) {
             m_msg_counter++;
             MessageBufferNode msgNode(g_eventQueue_ptr->getTime() + 1,
                                       m_msg_counter,
                                       (map_iter->second).front());

             m_prio_heap.push_back(msgNode);
             push_heap(m_prio_heap.begin(), m_prio_heap.end(),
                       greater<MessageBufferNode>());

             g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr,
                                                     msgNode.m_time);
             (map_iter->second).pop_front();
         }
     }
     m_stall_msg_map.clear();
 }

 void
 MessageBuffer::stallMessage(const Address& addr)
 {
     DPRINTF(RubyQueue, "Stalling due to %s\n", addr);
     assert(isReady());
     assert(addr.getOffset() == 0);
     MsgPtr message = m_prio_heap.front().m_msgptr;

     pop();

     //
     // Note: no event is scheduled to analyze the map at a later time.
     // Instead the controller is responsible to call reanalyzeMessages when
     // these addresses change state.
     //
     (m_stall_msg_map[addr]).push_back(message);
 }

 int
 MessageBuffer::setAndReturnDelayCycles(MsgPtr msg_ptr)
 {
     int delay_cycles = -1;  // null value

     // get the delay cycles of the message at the top of the queue

     // this function should only be called on dequeue
     // ensure the msg hasn't been enqueued
     assert(msg_ptr->getLastEnqueueTime() <= g_eventQueue_ptr->getTime());
     msg_ptr->setDelayedCycles(g_eventQueue_ptr->getTime() -
                               msg_ptr->getLastEnqueueTime() +
                               msg_ptr->getDelayedCycles());
     delay_cycles = msg_ptr->getDelayedCycles();

     assert(delay_cycles >= 0);
     return delay_cycles;
 }

 void
 MessageBuffer::print(ostream& out) const
 {
     ccprintf(out, "[MessageBuffer: ");
     if (m_consumer_ptr != NULL) {
         ccprintf(out, " consumer-yes ");
     }

     vector<MessageBufferNode> copy(m_prio_heap);
     sort_heap(copy.begin(), copy.end(), greater<MessageBufferNode>());
     ccprintf(out, "%s] %s", copy, m_name);
 }

 void
 MessageBuffer::printStats(ostream& out)
 {
     out << "MessageBuffer: " << m_name << " stats - msgs:" << m_msg_counter
         << " full:" << m_not_avail_count << endl;
 }
	/*
	* Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met: redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer;
	* redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution;
	* neither the name of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include <cassert>

	#include "base/cprintf.hh"
	#include "base/misc.hh"
	#include "base/stl_helpers.hh"
	#include "debug/RubyQueue.hh"
	#include "mem/ruby/buffers/MessageBuffer.hh"
	#include "mem/ruby/system/System.hh"

	using namespace std;
	using m5::stl_helpers::operator<<;

	MessageBuffer::MessageBuffer(const string &name)
	{
	m_msg_counter = 0;
	m_consumer_ptr = NULL;
	m_ordering_set = false;
	m_strict_fifo = true;
	m_size = 0;
	m_max_size = -1;
	m_last_arrival_time = 0;
	m_randomization = true;
	m_size_last_time_size_checked = 0;
	m_time_last_time_size_checked = 0;
	m_time_last_time_enqueue = 0;
	m_time_last_time_pop = 0;
	m_size_at_cycle_start = 0;
	m_msgs_this_cycle = 0;
	m_not_avail_count = 0;
	m_priority_rank = 0;
	m_name = name;

	m_stall_msg_map.clear();
	m_input_link_id = 0;
	m_vnet_id = 0;
	}

	int
	MessageBuffer::getSize()
	{
	if (m_time_last_time_size_checked == g_eventQueue_ptr->getTime()) {
	return m_size_last_time_size_checked;
	} else {
	m_time_last_time_size_checked = g_eventQueue_ptr->getTime();
	m_size_last_time_size_checked = m_size;
	return m_size;
	}
	}

	bool
	MessageBuffer::areNSlotsAvailable(int n)
	{

	// fast path when message buffers have infinite size
	if (m_max_size == -1) {
	return true;
	}

	// determine my correct size for the current cycle
	// pop operations shouldn't effect the network's visible size
	// until next cycle, but enqueue operations effect the visible
	// size immediately
	int current_size = max(m_size_at_cycle_start, m_size);
	if (m_time_last_time_pop < g_eventQueue_ptr->getTime()) {
	// no pops this cycle - m_size is correct
	current_size = m_size;
	} else {
	if (m_time_last_time_enqueue < g_eventQueue_ptr->getTime()) {
	// no enqueues this cycle - m_size_at_cycle_start is correct
	current_size = m_size_at_cycle_start;
	} else {
	// both pops and enqueues occured this cycle - add new
	// enqueued msgs to m_size_at_cycle_start
	current_size = m_size_at_cycle_start+m_msgs_this_cycle;
	}
	}

	// now compare the new size with our max size
	if (current_size + n <= m_max_size) {
	return true;
	} else {
	DPRINTF(RubyQueue, "n: %d, current_size: %d, m_size: %d, "
	"m_max_size: %d\n",
	n, current_size, m_size, m_max_size);
	m_not_avail_count++;
	return false;
	}
	}

	const MsgPtr
	MessageBuffer::getMsgPtrCopy() const
	{
	assert(isReady());

	return m_prio_heap.front().m_msgptr->clone();
	}

	const Message*
	MessageBuffer::peekAtHeadOfQueue() const
	{
	DPRINTF(RubyQueue, "Peeking at head of queue.\n");
	assert(isReady());

	const Message* msg_ptr = m_prio_heap.front().m_msgptr.get();
	assert(msg_ptr);

	DPRINTF(RubyQueue, "Message: %s\n", (*msg_ptr));
	return msg_ptr;
	}

	// FIXME - move me somewhere else
	int
	random_time()
	{
	int time = 1;
	time += random() & 0x3; // [0...3]
	if ((random() & 0x7) == 0) { // 1 in 8 chance
	time += 100 + (random() % 0xf); // 100 + [1...15]
	}
	return time;
	}

	void
	MessageBuffer::enqueue(MsgPtr message, Time delta)
	{
	m_msg_counter++;
	m_size++;

	// record current time incase we have a pop that also adjusts my size
	if (m_time_last_time_enqueue < g_eventQueue_ptr->getTime()) {
	m_msgs_this_cycle = 0; // first msg this cycle
	m_time_last_time_enqueue = g_eventQueue_ptr->getTime();
	}
	m_msgs_this_cycle++;

	if (!m_ordering_set) {
	panic("Ordering property of %s has not been set", m_name);
	}

	// Calculate the arrival time of the message, that is, the first
	// cycle the message can be dequeued.
	assert(delta>0);
	Time current_time = g_eventQueue_ptr->getTime();
	Time arrival_time = 0;
	if (!RubySystem::getRandomization() \|\| (m_randomization == false)) {
	// No randomization
	arrival_time = current_time + delta;
	} else {
	// Randomization - ignore delta
	if (m_strict_fifo) {
	if (m_last_arrival_time < current_time) {
	m_last_arrival_time = current_time;
	}
	arrival_time = m_last_arrival_time + random_time();
	} else {
	arrival_time = current_time + random_time();
	}
	}

	// Check the arrival time
	assert(arrival_time > current_time);
	if (m_strict_fifo) {
	if (arrival_time < m_last_arrival_time) {
	panic("FIFO ordering violated: %s name: %s current time: %d "
	"delta: %d arrival_time: %d last arrival_time: %d\n",
	*this, m_name,
	current_time * g_eventQueue_ptr->getClock(),
	delta * g_eventQueue_ptr->getClock(),
	arrival_time * g_eventQueue_ptr->getClock(),
	m_last_arrival_time * g_eventQueue_ptr->getClock());
	}
	}

	// If running a cache trace, don't worry about the last arrival checks
	if (!g_system_ptr->m_warmup_enabled) {
	m_last_arrival_time = arrival_time;
	}

	// compute the delay cycles and set enqueue time
	Message* msg_ptr = message.get();
	assert(msg_ptr != NULL);

	assert(g_eventQueue_ptr->getTime() >= msg_ptr->getLastEnqueueTime() &&
	"ensure we aren't dequeued early");

	msg_ptr->setDelayedCycles(g_eventQueue_ptr->getTime() -
	msg_ptr->getLastEnqueueTime() +
	msg_ptr->getDelayedCycles());
	msg_ptr->setLastEnqueueTime(arrival_time);

	// Insert the message into the priority heap
	MessageBufferNode thisNode(arrival_time, m_msg_counter, message);
	m_prio_heap.push_back(thisNode);
	push_heap(m_prio_heap.begin(), m_prio_heap.end(),
	greater<MessageBufferNode>());

	DPRINTF(RubyQueue, "Enqueue with arrival_time %lld.\n",
	arrival_time * g_eventQueue_ptr->getClock());
	DPRINTF(RubyQueue, "Enqueue Message: %s.\n", (*(message.get())));

	// Schedule the wakeup
	if (m_consumer_ptr != NULL) {
	g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, arrival_time);
	m_consumer_ptr->storeEventInfo(m_vnet_id);
	} else {
	panic("No consumer: %s name: %s\n", *this, m_name);
	}
	}

	int
	MessageBuffer::dequeue_getDelayCycles(MsgPtr& message)
	{
	int delay_cycles = -1; // null value

	dequeue(message);

	// get the delay cycles
	delay_cycles = setAndReturnDelayCycles(message);

	assert(delay_cycles >= 0);
	return delay_cycles;
	}

	void
	MessageBuffer::dequeue(MsgPtr& message)
	{
	DPRINTF(RubyQueue, "Dequeueing\n");
	message = m_prio_heap.front().m_msgptr;

	pop();
	DPRINTF(RubyQueue, "Enqueue message is %s\n", (*(message.get())));
	}

	int
	MessageBuffer::dequeue_getDelayCycles()
	{
	int delay_cycles = -1; // null value

	// get MsgPtr of the message about to be dequeued
	MsgPtr message = m_prio_heap.front().m_msgptr;

	// get the delay cycles
	delay_cycles = setAndReturnDelayCycles(message);

	dequeue();

	assert(delay_cycles >= 0);
	return delay_cycles;
	}

	void
	MessageBuffer::pop()
	{
	DPRINTF(RubyQueue, "Popping\n");
	assert(isReady());
	pop_heap(m_prio_heap.begin(), m_prio_heap.end(),
	greater<MessageBufferNode>());
	m_prio_heap.pop_back();

	// record previous size and time so the current buffer size isn't
	// adjusted until next cycle
	if (m_time_last_time_pop < g_eventQueue_ptr->getTime()) {
	m_size_at_cycle_start = m_size;
	m_time_last_time_pop = g_eventQueue_ptr->getTime();
	}
	m_size--;
	}

	void
	MessageBuffer::clear()
	{
	m_prio_heap.clear();

	m_msg_counter = 0;
	m_size = 0;
	m_time_last_time_enqueue = 0;
	m_time_last_time_pop = 0;
	m_size_at_cycle_start = 0;
	m_msgs_this_cycle = 0;
	}

	void
	MessageBuffer::recycle()
	{
	DPRINTF(RubyQueue, "Recycling.\n");
	assert(isReady());
	MessageBufferNode node = m_prio_heap.front();
	pop_heap(m_prio_heap.begin(), m_prio_heap.end(),
	greater<MessageBufferNode>());
	node.m_time = g_eventQueue_ptr->getTime() + m_recycle_latency;
	m_prio_heap.back() = node;
	push_heap(m_prio_heap.begin(), m_prio_heap.end(),
	greater<MessageBufferNode>());
	g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr,
	g_eventQueue_ptr->getTime() + m_recycle_latency);
	}

	void
	MessageBuffer::reanalyzeMessages(const Address& addr)
	{
	DPRINTF(RubyQueue, "ReanalyzeMessages\n");
	assert(m_stall_msg_map.count(addr) > 0);

	//
	// Put all stalled messages associated with this address back on the
	// prio heap
	//
	while(!m_stall_msg_map[addr].empty()) {
	m_msg_counter++;
	MessageBufferNode msgNode(g_eventQueue_ptr->getTime() + 1,
	m_msg_counter,
	m_stall_msg_map[addr].front());

	m_prio_heap.push_back(msgNode);
	push_heap(m_prio_heap.begin(), m_prio_heap.end(),
	greater<MessageBufferNode>());

	g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, msgNode.m_time);
	m_stall_msg_map[addr].pop_front();
	}
	m_stall_msg_map.erase(addr);
	}

	void
	MessageBuffer::reanalyzeAllMessages()
	{
	DPRINTF(RubyQueue, "ReanalyzeAllMessages %s\n");

	//
	// Put all stalled messages associated with this address back on the
	// prio heap
	//
	for (StallMsgMapType::iterator map_iter = m_stall_msg_map.begin();
	map_iter != m_stall_msg_map.end();
	++map_iter) {

	while(!(map_iter->second).empty()) {
	m_msg_counter++;
	MessageBufferNode msgNode(g_eventQueue_ptr->getTime() + 1,
	m_msg_counter,
	(map_iter->second).front());

	m_prio_heap.push_back(msgNode);
	push_heap(m_prio_heap.begin(), m_prio_heap.end(),
	greater<MessageBufferNode>());

	g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr,
	msgNode.m_time);
	(map_iter->second).pop_front();
	}
	}
	m_stall_msg_map.clear();
	}

	void
	MessageBuffer::stallMessage(const Address& addr)
	{
	DPRINTF(RubyQueue, "Stalling due to %s\n", addr);
	assert(isReady());
	assert(addr.getOffset() == 0);
	MsgPtr message = m_prio_heap.front().m_msgptr;

	pop();

	//
	// Note: no event is scheduled to analyze the map at a later time.
	// Instead the controller is responsible to call reanalyzeMessages when
	// these addresses change state.
	//
	(m_stall_msg_map[addr]).push_back(message);
	}

	int
	MessageBuffer::setAndReturnDelayCycles(MsgPtr msg_ptr)
	{
	int delay_cycles = -1; // null value

	// get the delay cycles of the message at the top of the queue

	// this function should only be called on dequeue
	// ensure the msg hasn't been enqueued
	assert(msg_ptr->getLastEnqueueTime() <= g_eventQueue_ptr->getTime());
	msg_ptr->setDelayedCycles(g_eventQueue_ptr->getTime() -
	msg_ptr->getLastEnqueueTime() +
	msg_ptr->getDelayedCycles());
	delay_cycles = msg_ptr->getDelayedCycles();

	assert(delay_cycles >= 0);
	return delay_cycles;
	}

	void
	MessageBuffer::print(ostream& out) const
	{
	ccprintf(out, "[MessageBuffer: ");
	if (m_consumer_ptr != NULL) {
	ccprintf(out, " consumer-yes ");
	}

	vector<MessageBufferNode> copy(m_prio_heap);
	sort_heap(copy.begin(), copy.end(), greater<MessageBufferNode>());
	ccprintf(out, "%s] %s", copy, m_name);
	}

	void
	MessageBuffer::printStats(ostream& out)
	{
	out << "MessageBuffer: " << m_name << " stats - msgs:" << m_msg_counter
	<< " full:" << m_not_avail_count << endl;
	}