xref: /gem5/src/mem/ruby/network/simple/Throttle.cc

/*
 * 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.
 */

/*
 * $Id$
 *
 * Description: see Throttle.h
 *
 */

#include "mem/ruby/network/simple/Throttle.hh"
#include "mem/ruby/buffers/MessageBuffer.hh"
#include "mem/ruby/network/Network.hh"
#include "mem/ruby/system/System.hh"
#include "mem/ruby/slicc_interface/NetworkMessage.hh"
#include "mem/protocol/Protocol.hh"

const int HIGH_RANGE = 256;
const int ADJUST_INTERVAL = 50000;
const int MESSAGE_SIZE_MULTIPLIER = 1000;
//const int BROADCAST_SCALING = 4; // Have a 16p system act like a 64p systems
const int BROADCAST_SCALING = 1;
const int PRIORITY_SWITCH_LIMIT = 128;

static int network_message_to_size(NetworkMessage* net_msg_ptr);

extern std::ostream * debug_cout_ptr;

Throttle::Throttle(int sID, NodeID node, int link_latency, int link_bandwidth_multiplier)
{
  init(node, link_latency, link_bandwidth_multiplier);
  m_sID = sID;
}

Throttle::Throttle(NodeID node, int link_latency, int link_bandwidth_multiplier)
{
  init(node, link_latency, link_bandwidth_multiplier);
  m_sID = 0;
}

void Throttle::init(NodeID node, int link_latency, int link_bandwidth_multiplier)
{
  m_node = node;
  m_vnets = 0;

  ASSERT(link_bandwidth_multiplier > 0);
  m_link_bandwidth_multiplier = link_bandwidth_multiplier;
  m_link_latency = link_latency;

  m_bash_counter = HIGH_RANGE;
  m_bandwidth_since_sample = 0;
  m_last_bandwidth_sample = 0;
  m_wakeups_wo_switch = 0;
  clearStats();
}

void Throttle::clear()
{
  for (int counter = 0; counter < m_vnets; counter++) {
    m_in[counter]->clear();
    m_out[counter]->clear();
  }
}

void Throttle::addLinks(const Vector<MessageBuffer*>& in_vec, const Vector<MessageBuffer*>& out_vec)
{
  assert(in_vec.size() == out_vec.size());
  for (int i=0; i<in_vec.size(); i++) {
    addVirtualNetwork(in_vec[i], out_vec[i]);
  }

  m_message_counters.setSize(MessageSizeType_NUM);
  for (int i=0; i<MessageSizeType_NUM; i++) {
    m_message_counters[i].setSize(in_vec.size());
    for (int j=0; j<m_message_counters[i].size(); j++) {
      m_message_counters[i][j] = 0;
    }
  }

  if (g_PRINT_TOPOLOGY) {
    m_out_link_vec.insertAtBottom(out_vec);
  }
}

void Throttle::addVirtualNetwork(MessageBuffer* in_ptr, MessageBuffer* out_ptr)
{
  m_units_remaining.insertAtBottom(0);
  m_in.insertAtBottom(in_ptr);
  m_out.insertAtBottom(out_ptr);

  // Set consumer and description
  m_in[m_vnets]->setConsumer(this);
  string desc = "[Queue to Throttle " + NodeIDToString(m_sID) + " " + NodeIDToString(m_node) + "]";
  m_in[m_vnets]->setDescription(desc);
  m_vnets++;
}

void Throttle::wakeup()
{
  // Limits the number of message sent to a limited number of bytes/cycle.
  assert(getLinkBandwidth() > 0);
  int bw_remaining = getLinkBandwidth();

  // Give the highest numbered link priority most of the time
  m_wakeups_wo_switch++;
  int highest_prio_vnet = m_vnets-1;
  int lowest_prio_vnet = 0;
  int counter = 1;
  bool schedule_wakeup = false;

  // invert priorities to avoid starvation seen in the component network
  if (m_wakeups_wo_switch > PRIORITY_SWITCH_LIMIT) {
    m_wakeups_wo_switch = 0;
    highest_prio_vnet = 0;
    lowest_prio_vnet = m_vnets-1;
    counter = -1;
  }

  for (int vnet = highest_prio_vnet; (vnet*counter) >= (counter*lowest_prio_vnet); vnet -= counter) {

    assert(m_out[vnet] != NULL);
    assert(m_in[vnet] != NULL);
    assert(m_units_remaining[vnet] >= 0);

    while ((bw_remaining > 0) && ((m_in[vnet]->isReady()) || (m_units_remaining[vnet] > 0)) && m_out[vnet]->areNSlotsAvailable(1)) {

      // See if we are done transferring the previous message on this virtual network
      if (m_units_remaining[vnet] == 0 && m_in[vnet]->isReady()) {

        // Find the size of the message we are moving
        MsgPtr msg_ptr = m_in[vnet]->peekMsgPtr();
        NetworkMessage* net_msg_ptr = dynamic_cast<NetworkMessage*>(msg_ptr.ref());
        m_units_remaining[vnet] += network_message_to_size(net_msg_ptr);

        DEBUG_NEWLINE(NETWORK_COMP,HighPrio);
        DEBUG_MSG(NETWORK_COMP,HighPrio,"throttle: " + int_to_string(m_node)
                  + " my bw " + int_to_string(getLinkBandwidth())
                  + " bw spent enqueueing net msg " + int_to_string(m_units_remaining[vnet])
                  + " time: " + int_to_string(g_eventQueue_ptr->getTime()) + ".");

        // Move the message
        m_out[vnet]->enqueue(m_in[vnet]->peekMsgPtr(), m_link_latency);
        m_in[vnet]->pop();

        // Count the message
        m_message_counters[net_msg_ptr->getMessageSize()][vnet]++;

        DEBUG_MSG(NETWORK_COMP,LowPrio,*m_out[vnet]);
        DEBUG_NEWLINE(NETWORK_COMP,HighPrio);
      }

      // Calculate the amount of bandwidth we spent on this message
      int diff = m_units_remaining[vnet] - bw_remaining;
      m_units_remaining[vnet] = max(0, diff);
      bw_remaining = max(0, -diff);
    }

    if ((bw_remaining > 0) && ((m_in[vnet]->isReady()) || (m_units_remaining[vnet] > 0)) && !m_out[vnet]->areNSlotsAvailable(1)) {
      DEBUG_MSG(NETWORK_COMP,LowPrio,vnet);
      schedule_wakeup = true; // schedule me to wakeup again because I'm waiting for my output queue to become available
    }
  }

  // We should only wake up when we use the bandwidth
  //  assert(bw_remaining != getLinkBandwidth());  // This is only mostly true

  // Record that we used some or all of the link bandwidth this cycle
  double ratio = 1.0-(double(bw_remaining)/double(getLinkBandwidth()));
  // If ratio = 0, we used no bandwidth, if ratio = 1, we used all
  linkUtilized(ratio);

  // Sample the link bandwidth utilization over a number of cycles
  int bw_used = getLinkBandwidth()-bw_remaining;
  m_bandwidth_since_sample += bw_used;

  // FIXME - comment out the bash specific code for faster performance
  // Start Bash code
  // Update the predictor
  Time current_time = g_eventQueue_ptr->getTime();
  while ((current_time - m_last_bandwidth_sample) > ADJUST_INTERVAL) {
    double utilization = m_bandwidth_since_sample/double(ADJUST_INTERVAL * getLinkBandwidth());

    if (utilization > g_bash_bandwidth_adaptive_threshold) {
      // Used more bandwidth
      m_bash_counter++;
    } else {
      // Used less bandwidth
      m_bash_counter--;
    }

    // Make sure we don't overflow
    m_bash_counter = min(HIGH_RANGE, m_bash_counter);
    m_bash_counter = max(0, m_bash_counter);

    // Reset samples
    m_last_bandwidth_sample += ADJUST_INTERVAL;
    m_bandwidth_since_sample = 0;
  }
  // End Bash code

  if ((bw_remaining > 0) && !schedule_wakeup) {
    // We have extra bandwidth and our output buffer was available, so we must not have anything else to do until another message arrives.
    DEBUG_MSG(NETWORK_COMP,LowPrio,*this);
    DEBUG_MSG(NETWORK_COMP,LowPrio,"not scheduled again");
  } else {
    DEBUG_MSG(NETWORK_COMP,LowPrio,*this);
    DEBUG_MSG(NETWORK_COMP,LowPrio,"scheduled again");
    // We are out of bandwidth for this cycle, so wakeup next cycle and continue
    g_eventQueue_ptr->scheduleEvent(this, 1);
  }
}

bool Throttle::broadcastBandwidthAvailable(int rand) const
{
  bool result =  !(m_bash_counter > ((HIGH_RANGE/4) + (rand % (HIGH_RANGE/2))));
  return result;
}

void Throttle::printStats(ostream& out) const
{
  out << "utilized_percent: " << getUtilization() << endl;
}

void Throttle::clearStats()
{
  m_ruby_start = g_eventQueue_ptr->getTime();
  m_links_utilized = 0.0;

  for (int i=0; i<m_message_counters.size(); i++) {
    for (int j=0; j<m_message_counters[i].size(); j++) {
      m_message_counters[i][j] = 0;
    }
  }
}

void Throttle::printConfig(ostream& out) const
{

}

double Throttle::getUtilization() const
{
  return (100.0 * double(m_links_utilized)) / (double(g_eventQueue_ptr->getTime()-m_ruby_start));
}

void Throttle::print(ostream& out) const
{
  out << "[Throttle: " << m_sID << " " << m_node << " bw: " << getLinkBandwidth() << "]";
}

// Helper function

static
int network_message_to_size(NetworkMessage* net_msg_ptr)
{
  assert(net_msg_ptr != NULL);

  // Artificially increase the size of broadcast messages
  if (BROADCAST_SCALING > 1) {
    if (net_msg_ptr->getDestination().isBroadcast()) {
      return (MessageSizeType_to_int(net_msg_ptr->getMessageSize()) * MESSAGE_SIZE_MULTIPLIER * BROADCAST_SCALING);
    }
  }
  return (MessageSizeType_to_int(net_msg_ptr->getMessageSize()) * MESSAGE_SIZE_MULTIPLIER);
}