Topology.cc revision 11096
1/* 2 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#include <cassert> 30 31#include "base/trace.hh" 32#include "debug/RubyNetwork.hh" 33#include "mem/ruby/common/NetDest.hh" 34#include "mem/ruby/network/BasicLink.hh" 35#include "mem/ruby/network/Topology.hh" 36#include "mem/ruby/slicc_interface/AbstractController.hh" 37 38using namespace std; 39 40const int INFINITE_LATENCY = 10000; // Yes, this is a big hack 41 42// Note: In this file, we use the first 2*m_nodes SwitchIDs to 43// represent the input and output endpoint links. These really are 44// not 'switches', as they will not have a Switch object allocated for 45// them. The first m_nodes SwitchIDs are the links into the network, 46// the second m_nodes set of SwitchIDs represent the the output queues 47// of the network. 48 49Topology::Topology(uint32_t num_routers, 50 const vector<BasicExtLink *> &ext_links, 51 const vector<BasicIntLink *> &int_links) 52 : m_nodes(ext_links.size()), m_number_of_switches(num_routers), 53 m_ext_link_vector(ext_links), m_int_link_vector(int_links) 54{ 55 // Total nodes/controllers in network 56 assert(m_nodes > 1); 57 58 // analyze both the internal and external links, create data structures 59 // Note that the python created links are bi-directional, but that the 60 // topology and networks utilize uni-directional links. Thus each 61 // BasicLink is converted to two calls to add link, on for each direction 62 for (vector<BasicExtLink*>::const_iterator i = ext_links.begin(); 63 i != ext_links.end(); ++i) { 64 BasicExtLink *ext_link = (*i); 65 AbstractController *abs_cntrl = ext_link->params()->ext_node; 66 BasicRouter *router = ext_link->params()->int_node; 67 68 int machine_base_idx = MachineType_base_number(abs_cntrl->getType()); 69 int ext_idx1 = machine_base_idx + abs_cntrl->getVersion(); 70 int ext_idx2 = ext_idx1 + m_nodes; 71 int int_idx = router->params()->router_id + 2*m_nodes; 72 73 // create the internal uni-directional links in both directions 74 // the first direction is marked: In 75 addLink(ext_idx1, int_idx, ext_link, LinkDirection_In); 76 // the first direction is marked: Out 77 addLink(int_idx, ext_idx2, ext_link, LinkDirection_Out); 78 } 79 80 for (vector<BasicIntLink*>::const_iterator i = int_links.begin(); 81 i != int_links.end(); ++i) { 82 BasicIntLink *int_link = (*i); 83 BasicRouter *router_a = int_link->params()->node_a; 84 BasicRouter *router_b = int_link->params()->node_b; 85 86 // Store the IntLink pointers for later 87 m_int_link_vector.push_back(int_link); 88 89 int a = router_a->params()->router_id + 2*m_nodes; 90 int b = router_b->params()->router_id + 2*m_nodes; 91 92 // create the internal uni-directional links in both directions 93 // the first direction is marked: In 94 addLink(a, b, int_link, LinkDirection_In); 95 // the second direction is marked: Out 96 addLink(b, a, int_link, LinkDirection_Out); 97 } 98} 99 100void 101Topology::createLinks(Network *net) 102{ 103 // Find maximum switchID 104 SwitchID max_switch_id = 0; 105 for (LinkMap::const_iterator i = m_link_map.begin(); 106 i != m_link_map.end(); ++i) { 107 std::pair<SwitchID, SwitchID> src_dest = (*i).first; 108 max_switch_id = max(max_switch_id, src_dest.first); 109 max_switch_id = max(max_switch_id, src_dest.second); 110 } 111 112 // Initialize weight, latency, and inter switched vectors 113 int num_switches = max_switch_id+1; 114 Matrix topology_weights(num_switches, 115 vector<int>(num_switches, INFINITE_LATENCY)); 116 Matrix component_latencies(num_switches, 117 vector<int>(num_switches, -1)); 118 Matrix component_inter_switches(num_switches, 119 vector<int>(num_switches, 0)); 120 121 // Set identity weights to zero 122 for (int i = 0; i < topology_weights.size(); i++) { 123 topology_weights[i][i] = 0; 124 } 125 126 // Fill in the topology weights and bandwidth multipliers 127 for (LinkMap::const_iterator i = m_link_map.begin(); 128 i != m_link_map.end(); ++i) { 129 std::pair<int, int> src_dest = (*i).first; 130 BasicLink* link = (*i).second.link; 131 int src = src_dest.first; 132 int dst = src_dest.second; 133 component_latencies[src][dst] = link->m_latency; 134 topology_weights[src][dst] = link->m_weight; 135 } 136 137 // Walk topology and hookup the links 138 Matrix dist = shortest_path(topology_weights, component_latencies, 139 component_inter_switches); 140 141 for (int i = 0; i < topology_weights.size(); i++) { 142 for (int j = 0; j < topology_weights[i].size(); j++) { 143 int weight = topology_weights[i][j]; 144 if (weight > 0 && weight != INFINITE_LATENCY) { 145 NetDest destination_set = 146 shortest_path_to_node(i, j, topology_weights, dist); 147 makeLink(net, i, j, destination_set); 148 } 149 } 150 } 151} 152 153void 154Topology::addLink(SwitchID src, SwitchID dest, BasicLink* link, 155 LinkDirection dir) 156{ 157 assert(src <= m_number_of_switches+m_nodes+m_nodes); 158 assert(dest <= m_number_of_switches+m_nodes+m_nodes); 159 160 std::pair<int, int> src_dest_pair; 161 LinkEntry link_entry; 162 163 src_dest_pair.first = src; 164 src_dest_pair.second = dest; 165 link_entry.direction = dir; 166 link_entry.link = link; 167 m_link_map[src_dest_pair] = link_entry; 168} 169 170void 171Topology::makeLink(Network *net, SwitchID src, SwitchID dest, 172 const NetDest& routing_table_entry) 173{ 174 // Make sure we're not trying to connect two end-point nodes 175 // directly together 176 assert(src >= 2 * m_nodes || dest >= 2 * m_nodes); 177 178 std::pair<int, int> src_dest; 179 LinkEntry link_entry; 180 181 if (src < m_nodes) { 182 src_dest.first = src; 183 src_dest.second = dest; 184 link_entry = m_link_map[src_dest]; 185 net->makeInLink(src, dest - (2 * m_nodes), link_entry.link, 186 link_entry.direction, routing_table_entry); 187 } else if (dest < 2*m_nodes) { 188 assert(dest >= m_nodes); 189 NodeID node = dest - m_nodes; 190 src_dest.first = src; 191 src_dest.second = dest; 192 link_entry = m_link_map[src_dest]; 193 net->makeOutLink(src - (2 * m_nodes), node, link_entry.link, 194 link_entry.direction, routing_table_entry); 195 } else { 196 assert((src >= 2 * m_nodes) && (dest >= 2 * m_nodes)); 197 src_dest.first = src; 198 src_dest.second = dest; 199 link_entry = m_link_map[src_dest]; 200 net->makeInternalLink(src - (2 * m_nodes), dest - (2 * m_nodes), 201 link_entry.link, link_entry.direction, 202 routing_table_entry); 203 } 204} 205 206// The following all-pairs shortest path algorithm is based on the 207// discussion from Cormen et al., Chapter 26.1. 208void 209Topology::extend_shortest_path(Matrix ¤t_dist, Matrix &latencies, 210 Matrix &inter_switches) 211{ 212 bool change = true; 213 int nodes = current_dist.size(); 214 215 while (change) { 216 change = false; 217 for (int i = 0; i < nodes; i++) { 218 for (int j = 0; j < nodes; j++) { 219 int minimum = current_dist[i][j]; 220 int previous_minimum = minimum; 221 int intermediate_switch = -1; 222 for (int k = 0; k < nodes; k++) { 223 minimum = min(minimum, 224 current_dist[i][k] + current_dist[k][j]); 225 if (previous_minimum != minimum) { 226 intermediate_switch = k; 227 inter_switches[i][j] = 228 inter_switches[i][k] + 229 inter_switches[k][j] + 1; 230 } 231 previous_minimum = minimum; 232 } 233 if (current_dist[i][j] != minimum) { 234 change = true; 235 current_dist[i][j] = minimum; 236 assert(intermediate_switch >= 0); 237 assert(intermediate_switch < latencies[i].size()); 238 latencies[i][j] = latencies[i][intermediate_switch] + 239 latencies[intermediate_switch][j]; 240 } 241 } 242 } 243 } 244} 245 246Matrix 247Topology::shortest_path(const Matrix &weights, Matrix &latencies, 248 Matrix &inter_switches) 249{ 250 Matrix dist = weights; 251 extend_shortest_path(dist, latencies, inter_switches); 252 return dist; 253} 254 255bool 256Topology::link_is_shortest_path_to_node(SwitchID src, SwitchID next, 257 SwitchID final, const Matrix &weights, 258 const Matrix &dist) 259{ 260 return weights[src][next] + dist[next][final] == dist[src][final]; 261} 262 263NetDest 264Topology::shortest_path_to_node(SwitchID src, SwitchID next, 265 const Matrix &weights, const Matrix &dist) 266{ 267 NetDest result; 268 int d = 0; 269 int machines; 270 int max_machines; 271 272 machines = MachineType_NUM; 273 max_machines = MachineType_base_number(MachineType_NUM); 274 275 for (int m = 0; m < machines; m++) { 276 for (NodeID i = 0; i < MachineType_base_count((MachineType)m); i++) { 277 // we use "d+max_machines" below since the "destination" 278 // switches for the machines are numbered 279 // [MachineType_base_number(MachineType_NUM)... 280 // 2*MachineType_base_number(MachineType_NUM)-1] for the 281 // component network 282 if (link_is_shortest_path_to_node(src, next, d + max_machines, 283 weights, dist)) { 284 MachineID mach = {(MachineType)m, i}; 285 result.add(mach); 286 } 287 d++; 288 } 289 } 290 291 DPRINTF(RubyNetwork, "Returning shortest path\n" 292 "(src-(2*max_machines)): %d, (next-(2*max_machines)): %d, " 293 "src: %d, next: %d, result: %s\n", 294 (src-(2*max_machines)), (next-(2*max_machines)), 295 src, next, result); 296 297 return result; 298} 299