2698e73966
This patch tidies up random number generation to ensure that it is done consistently throughout the code base. In essence this involves a clean-up of Ruby, and some code simplifications in the traffic generator. As part of this patch a bunch of skewed distributions (off-by-one etc) have been fixed. Note that a single global random number generator is used, and that the object instantiation order will impact the behaviour (the sequence of numbers will be unaffected, but if module A calles random before module B then they would obviously see a different outcome). The dependency on the instantiation order is true in any case due to the execution-model of gem5, so we leave it as is. Also note that the global ranom generator is not thread safe at this point. Regressions using the memtest, TrafficGen or any Ruby tester are affected and will be updated accordingly.
321 lines
11 KiB
C++
321 lines
11 KiB
C++
/*
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* Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <algorithm>
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#include "base/cast.hh"
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#include "base/random.hh"
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#include "debug/RubyNetwork.hh"
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#include "mem/ruby/network/MessageBuffer.hh"
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#include "mem/ruby/network/simple/PerfectSwitch.hh"
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#include "mem/ruby/network/simple/SimpleNetwork.hh"
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#include "mem/ruby/network/simple/Switch.hh"
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#include "mem/ruby/slicc_interface/NetworkMessage.hh"
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using namespace std;
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const int PRIORITY_SWITCH_LIMIT = 128;
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// Operator for helper class
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bool
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operator<(const LinkOrder& l1, const LinkOrder& l2)
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{
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return (l1.m_value < l2.m_value);
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}
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PerfectSwitch::PerfectSwitch(SwitchID sid, Switch *sw, uint32_t virt_nets)
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: Consumer(sw)
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{
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m_switch_id = sid;
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m_round_robin_start = 0;
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m_wakeups_wo_switch = 0;
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m_virtual_networks = virt_nets;
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}
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void
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PerfectSwitch::init(SimpleNetwork *network_ptr)
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{
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m_network_ptr = network_ptr;
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for(int i = 0;i < m_virtual_networks;++i) {
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m_pending_message_count.push_back(0);
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}
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}
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void
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PerfectSwitch::addInPort(const map<int, MessageBuffer*>& in)
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{
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NodeID port = m_in.size();
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m_in.push_back(in);
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for (auto& it : in) {
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it.second->setConsumer(this);
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string desc = csprintf("[Queue from port %s %s %s to PerfectSwitch]",
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to_string(m_switch_id), to_string(port), to_string(it.first));
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it.second->setDescription(desc);
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it.second->setIncomingLink(port);
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it.second->setVnet(it.first);
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}
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}
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void
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PerfectSwitch::addOutPort(const map<int, MessageBuffer*>& out,
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const NetDest& routing_table_entry)
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{
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// Setup link order
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LinkOrder l;
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l.m_value = 0;
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l.m_link = m_out.size();
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m_link_order.push_back(l);
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// Add to routing table
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m_out.push_back(out);
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m_routing_table.push_back(routing_table_entry);
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}
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PerfectSwitch::~PerfectSwitch()
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{
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}
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void
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PerfectSwitch::operateVnet(int vnet)
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{
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MsgPtr msg_ptr;
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NetworkMessage* net_msg_ptr = NULL;
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// This is for round-robin scheduling
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int incoming = m_round_robin_start;
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m_round_robin_start++;
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if (m_round_robin_start >= m_in.size()) {
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m_round_robin_start = 0;
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}
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if(m_pending_message_count[vnet] > 0) {
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// for all input ports, use round robin scheduling
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for (int counter = 0; counter < m_in.size(); counter++) {
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// Round robin scheduling
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incoming++;
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if (incoming >= m_in.size()) {
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incoming = 0;
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}
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// temporary vectors to store the routing results
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vector<LinkID> output_links;
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vector<NetDest> output_link_destinations;
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// Is there a message waiting?
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auto it = m_in[incoming].find(vnet);
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if (it == m_in[incoming].end())
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continue;
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MessageBuffer *buffer = (*it).second;
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while (buffer->isReady()) {
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DPRINTF(RubyNetwork, "incoming: %d\n", incoming);
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// Peek at message
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msg_ptr = buffer->peekMsgPtr();
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net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
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DPRINTF(RubyNetwork, "Message: %s\n", (*net_msg_ptr));
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output_links.clear();
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output_link_destinations.clear();
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NetDest msg_dsts = net_msg_ptr->getInternalDestination();
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// Unfortunately, the token-protocol sends some
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// zero-destination messages, so this assert isn't valid
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// assert(msg_dsts.count() > 0);
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assert(m_link_order.size() == m_routing_table.size());
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assert(m_link_order.size() == m_out.size());
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if (m_network_ptr->getAdaptiveRouting()) {
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if (m_network_ptr->isVNetOrdered(vnet)) {
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// Don't adaptively route
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for (int out = 0; out < m_out.size(); out++) {
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m_link_order[out].m_link = out;
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m_link_order[out].m_value = 0;
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}
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} else {
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// Find how clogged each link is
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for (int out = 0; out < m_out.size(); out++) {
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int out_queue_length = 0;
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for (int v = 0; v < m_virtual_networks; v++) {
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out_queue_length += m_out[out][v]->getSize();
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}
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int value =
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(out_queue_length << 8) |
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random_mt.random(0, 0xff);
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m_link_order[out].m_link = out;
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m_link_order[out].m_value = value;
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}
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// Look at the most empty link first
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sort(m_link_order.begin(), m_link_order.end());
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}
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}
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for (int i = 0; i < m_routing_table.size(); i++) {
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// pick the next link to look at
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int link = m_link_order[i].m_link;
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NetDest dst = m_routing_table[link];
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DPRINTF(RubyNetwork, "dst: %s\n", dst);
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if (!msg_dsts.intersectionIsNotEmpty(dst))
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continue;
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// Remember what link we're using
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output_links.push_back(link);
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// Need to remember which destinations need this message in
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// another vector. This Set is the intersection of the
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// routing_table entry and the current destination set. The
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// intersection must not be empty, since we are inside "if"
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output_link_destinations.push_back(msg_dsts.AND(dst));
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// Next, we update the msg_destination not to include
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// those nodes that were already handled by this link
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msg_dsts.removeNetDest(dst);
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}
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assert(msg_dsts.count() == 0);
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// Check for resources - for all outgoing queues
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bool enough = true;
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for (int i = 0; i < output_links.size(); i++) {
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int outgoing = output_links[i];
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if (!m_out[outgoing][vnet]->areNSlotsAvailable(1))
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enough = false;
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DPRINTF(RubyNetwork, "Checking if node is blocked ..."
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"outgoing: %d, vnet: %d, enough: %d\n",
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outgoing, vnet, enough);
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}
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// There were not enough resources
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if (!enough) {
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scheduleEvent(Cycles(1));
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DPRINTF(RubyNetwork, "Can't deliver message since a node "
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"is blocked\n");
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DPRINTF(RubyNetwork, "Message: %s\n", (*net_msg_ptr));
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break; // go to next incoming port
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}
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MsgPtr unmodified_msg_ptr;
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if (output_links.size() > 1) {
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// If we are sending this message down more than one link
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// (size>1), we need to make a copy of the message so each
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// branch can have a different internal destination we need
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// to create an unmodified MsgPtr because the MessageBuffer
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// enqueue func will modify the message
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// This magic line creates a private copy of the message
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unmodified_msg_ptr = msg_ptr->clone();
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}
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// Dequeue msg
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buffer->dequeue();
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m_pending_message_count[vnet]--;
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// Enqueue it - for all outgoing queues
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for (int i=0; i<output_links.size(); i++) {
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int outgoing = output_links[i];
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if (i > 0) {
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// create a private copy of the unmodified message
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msg_ptr = unmodified_msg_ptr->clone();
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}
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// Change the internal destination set of the message so it
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// knows which destinations this link is responsible for.
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net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
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net_msg_ptr->getInternalDestination() =
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output_link_destinations[i];
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// Enqeue msg
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DPRINTF(RubyNetwork, "Enqueuing net msg from "
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"inport[%d][%d] to outport [%d][%d].\n",
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incoming, vnet, outgoing, vnet);
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m_out[outgoing][vnet]->enqueue(msg_ptr);
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}
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}
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}
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}
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}
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void
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PerfectSwitch::wakeup()
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{
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// Give the highest numbered link priority most of the time
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m_wakeups_wo_switch++;
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int highest_prio_vnet = m_virtual_networks-1;
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int lowest_prio_vnet = 0;
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int decrementer = 1;
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// invert priorities to avoid starvation seen in the component network
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if (m_wakeups_wo_switch > PRIORITY_SWITCH_LIMIT) {
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m_wakeups_wo_switch = 0;
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highest_prio_vnet = 0;
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lowest_prio_vnet = m_virtual_networks-1;
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decrementer = -1;
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}
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// For all components incoming queues
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for (int vnet = highest_prio_vnet;
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(vnet * decrementer) >= (decrementer * lowest_prio_vnet);
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vnet -= decrementer) {
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operateVnet(vnet);
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}
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}
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void
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PerfectSwitch::storeEventInfo(int info)
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{
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m_pending_message_count[info]++;
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}
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void
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PerfectSwitch::clearStats()
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{
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}
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void
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PerfectSwitch::collateStats()
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{
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}
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void
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PerfectSwitch::print(std::ostream& out) const
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{
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out << "[PerfectSwitch " << m_switch_id << "]";
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}
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