Topology.cc revision 9496
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/protocol/MachineType.hh"
34#include "mem/ruby/common/NetDest.hh"
35#include "mem/ruby/network/BasicLink.hh"
36#include "mem/ruby/network/Network.hh"
37#include "mem/ruby/network/Topology.hh"
38#include "mem/ruby/slicc_interface/AbstractController.hh"
39
40using namespace std;
41
42const int INFINITE_LATENCY = 10000; // Yes, this is a big hack
43
44// Note: In this file, we use the first 2*m_nodes SwitchIDs to
45// represent the input and output endpoint links.  These really are
46// not 'switches', as they will not have a Switch object allocated for
47// them. The first m_nodes SwitchIDs are the links into the network,
48// the second m_nodes set of SwitchIDs represent the the output queues
49// of the network.
50
51// Helper functions based on chapter 29 of Cormen et al.
52void extend_shortest_path(Matrix& current_dist, Matrix& latencies,
53    Matrix& inter_switches);
54Matrix shortest_path(const Matrix& weights, Matrix& latencies,
55    Matrix& inter_switches);
56bool link_is_shortest_path_to_node(SwitchID src, SwitchID next,
57    SwitchID final, const Matrix& weights, const Matrix& dist);
58NetDest shortest_path_to_node(SwitchID src, SwitchID next,
59    const Matrix& weights, const Matrix& dist);
60
61Topology::Topology(const Params *p)
62    : SimObject(p)
63{
64    m_print_config = p->print_config;
65    m_number_of_switches = p->routers.size();
66
67    // initialize component latencies record
68    m_component_latencies.resize(0);
69    m_component_inter_switches.resize(0);
70
71    // Total nodes/controllers in network
72    // Must make sure this is called after the State Machine constructors
73    m_nodes = MachineType_base_number(MachineType_NUM);
74    assert(m_nodes > 1);
75
76    if (m_nodes != params()->ext_links.size() &&
77        m_nodes != params()->ext_links.size()) {
78        fatal("m_nodes (%d) != ext_links vector length (%d)\n",
79              m_nodes, params()->ext_links.size());
80    }
81
82    // analyze both the internal and external links, create data structures
83    // Note that the python created links are bi-directional, but that the
84    // topology and networks utilize uni-directional links.  Thus each
85    // BasicLink is converted to two calls to add link, on for each direction
86    for (vector<BasicExtLink*>::const_iterator i = params()->ext_links.begin();
87         i != params()->ext_links.end(); ++i) {
88        BasicExtLink *ext_link = (*i);
89        AbstractController *abs_cntrl = ext_link->params()->ext_node;
90        BasicRouter *router = ext_link->params()->int_node;
91
92        // Store the ExtLink pointers for later
93        m_ext_link_vector.push_back(ext_link);
94
95        int ext_idx1 = abs_cntrl->params()->cntrl_id;
96        int ext_idx2 = ext_idx1 + m_nodes;
97        int int_idx = router->params()->router_id + 2*m_nodes;
98
99        // create the internal uni-directional links in both directions
100        //   the first direction is marked: In
101        addLink(ext_idx1, int_idx, ext_link, LinkDirection_In);
102        //   the first direction is marked: Out
103        addLink(int_idx, ext_idx2, ext_link, LinkDirection_Out);
104    }
105
106    for (vector<BasicIntLink*>::const_iterator i = params()->int_links.begin();
107         i != params()->int_links.end(); ++i) {
108        BasicIntLink *int_link = (*i);
109        BasicRouter *router_a = int_link->params()->node_a;
110        BasicRouter *router_b = int_link->params()->node_b;
111
112        // Store the IntLink pointers for later
113        m_int_link_vector.push_back(int_link);
114
115        int a = router_a->params()->router_id + 2*m_nodes;
116        int b = router_b->params()->router_id + 2*m_nodes;
117
118        // create the internal uni-directional links in both directions
119        //   the first direction is marked: In
120        addLink(a, b, int_link, LinkDirection_In);
121        //   the second direction is marked: Out
122        addLink(b, a, int_link, LinkDirection_Out);
123    }
124}
125
126void
127Topology::init()
128{
129}
130
131
132void
133Topology::initNetworkPtr(Network* net_ptr)
134{
135    for (vector<BasicExtLink*>::const_iterator i = params()->ext_links.begin();
136         i != params()->ext_links.end(); ++i) {
137        BasicExtLink *ext_link = (*i);
138        AbstractController *abs_cntrl = ext_link->params()->ext_node;
139        abs_cntrl->initNetworkPtr(net_ptr);
140    }
141}
142
143void
144Topology::createLinks(Network *net, bool isReconfiguration)
145{
146    // Find maximum switchID
147    SwitchID max_switch_id = 0;
148    for (LinkMap::const_iterator i = m_link_map.begin();
149         i != m_link_map.end(); ++i) {
150        std::pair<int, int> src_dest = (*i).first;
151        max_switch_id = max(max_switch_id, src_dest.first);
152        max_switch_id = max(max_switch_id, src_dest.second);
153    }
154
155    // Initialize weight, latency, and inter switched vectors
156    Matrix topology_weights;
157    int num_switches = max_switch_id+1;
158    topology_weights.resize(num_switches);
159    m_component_latencies.resize(num_switches);
160    m_component_inter_switches.resize(num_switches);
161
162    for (int i = 0; i < topology_weights.size(); i++) {
163        topology_weights[i].resize(num_switches);
164        m_component_latencies[i].resize(num_switches);
165        m_component_inter_switches[i].resize(num_switches);
166
167        for (int j = 0; j < topology_weights[i].size(); j++) {
168            topology_weights[i][j] = INFINITE_LATENCY;
169
170            // initialize to invalid values
171            m_component_latencies[i][j] = -1;
172
173            // initially assume direct connections / no intermediate
174            // switches between components
175            m_component_inter_switches[i][j] = 0;
176        }
177    }
178
179    // Set identity weights to zero
180    for (int i = 0; i < topology_weights.size(); i++) {
181        topology_weights[i][i] = 0;
182    }
183
184    // Fill in the topology weights and bandwidth multipliers
185    for (LinkMap::const_iterator i = m_link_map.begin();
186         i != m_link_map.end(); ++i) {
187        std::pair<int, int> src_dest = (*i).first;
188        BasicLink* link = (*i).second.link;
189        int src = src_dest.first;
190        int dst = src_dest.second;
191        m_component_latencies[src][dst] = link->m_latency;
192        topology_weights[src][dst] = link->m_weight;
193    }
194
195    // Walk topology and hookup the links
196    Matrix dist = shortest_path(topology_weights, m_component_latencies,
197        m_component_inter_switches);
198    for (int i = 0; i < topology_weights.size(); i++) {
199        for (int j = 0; j < topology_weights[i].size(); j++) {
200            int weight = topology_weights[i][j];
201            if (weight > 0 && weight != INFINITE_LATENCY) {
202                NetDest destination_set = shortest_path_to_node(i, j,
203                                                     topology_weights, dist);
204                makeLink(net, i, j, destination_set, isReconfiguration);
205            }
206        }
207    }
208}
209
210void
211Topology::addLink(SwitchID src, SwitchID dest, BasicLink* link,
212                  LinkDirection dir)
213{
214    assert(src <= m_number_of_switches+m_nodes+m_nodes);
215    assert(dest <= m_number_of_switches+m_nodes+m_nodes);
216
217    std::pair<int, int> src_dest_pair;
218    LinkEntry link_entry;
219
220    src_dest_pair.first = src;
221    src_dest_pair.second = dest;
222    link_entry.direction = dir;
223    link_entry.link = link;
224    m_link_map[src_dest_pair] = link_entry;
225}
226
227void
228Topology::makeLink(Network *net, SwitchID src, SwitchID dest,
229                   const NetDest& routing_table_entry, bool isReconfiguration)
230{
231    // Make sure we're not trying to connect two end-point nodes
232    // directly together
233    assert(src >= 2 * m_nodes || dest >= 2 * m_nodes);
234
235    std::pair<int, int> src_dest;
236    LinkEntry link_entry;
237
238    if (src < m_nodes) {
239        src_dest.first = src;
240        src_dest.second = dest;
241        link_entry = m_link_map[src_dest];
242        net->makeInLink(src, dest - (2 * m_nodes), link_entry.link,
243                        link_entry.direction,
244                        routing_table_entry,
245                        isReconfiguration);
246    } else if (dest < 2*m_nodes) {
247        assert(dest >= m_nodes);
248        NodeID node = dest - m_nodes;
249        src_dest.first = src;
250        src_dest.second = dest;
251        link_entry = m_link_map[src_dest];
252        net->makeOutLink(src - (2 * m_nodes), node, link_entry.link,
253                         link_entry.direction,
254                         routing_table_entry,
255                         isReconfiguration);
256    } else {
257        assert((src >= 2 * m_nodes) && (dest >= 2 * m_nodes));
258        src_dest.first = src;
259        src_dest.second = dest;
260        link_entry = m_link_map[src_dest];
261        net->makeInternalLink(src - (2 * m_nodes), dest - (2 * m_nodes),
262                              link_entry.link, link_entry.direction,
263                              routing_table_entry, isReconfiguration);
264    }
265}
266
267// The following all-pairs shortest path algorithm is based on the
268// discussion from Cormen et al., Chapter 26.1.
269void
270extend_shortest_path(Matrix& current_dist, Matrix& latencies,
271    Matrix& inter_switches)
272{
273    bool change = true;
274    int nodes = current_dist.size();
275
276    while (change) {
277        change = false;
278        for (int i = 0; i < nodes; i++) {
279            for (int j = 0; j < nodes; j++) {
280                int minimum = current_dist[i][j];
281                int previous_minimum = minimum;
282                int intermediate_switch = -1;
283                for (int k = 0; k < nodes; k++) {
284                    minimum = min(minimum,
285                        current_dist[i][k] + current_dist[k][j]);
286                    if (previous_minimum != minimum) {
287                        intermediate_switch = k;
288                        inter_switches[i][j] =
289                            inter_switches[i][k] +
290                            inter_switches[k][j] + 1;
291                    }
292                    previous_minimum = minimum;
293                }
294                if (current_dist[i][j] != minimum) {
295                    change = true;
296                    current_dist[i][j] = minimum;
297                    assert(intermediate_switch >= 0);
298                    assert(intermediate_switch < latencies[i].size());
299                    latencies[i][j] = latencies[i][intermediate_switch] +
300                        latencies[intermediate_switch][j];
301                }
302            }
303        }
304    }
305}
306
307Matrix
308shortest_path(const Matrix& weights, Matrix& latencies, Matrix& inter_switches)
309{
310    Matrix dist = weights;
311    extend_shortest_path(dist, latencies, inter_switches);
312    return dist;
313}
314
315bool
316link_is_shortest_path_to_node(SwitchID src, SwitchID next, SwitchID final,
317    const Matrix& weights, const Matrix& dist)
318{
319    return weights[src][next] + dist[next][final] == dist[src][final];
320}
321
322NetDest
323shortest_path_to_node(SwitchID src, SwitchID next, const Matrix& weights,
324    const Matrix& dist)
325{
326    NetDest result;
327    int d = 0;
328    int machines;
329    int max_machines;
330
331    machines = MachineType_NUM;
332    max_machines = MachineType_base_number(MachineType_NUM);
333
334    for (int m = 0; m < machines; m++) {
335        for (int i = 0; i < MachineType_base_count((MachineType)m); i++) {
336            // we use "d+max_machines" below since the "destination"
337            // switches for the machines are numbered
338            // [MachineType_base_number(MachineType_NUM)...
339            //  2*MachineType_base_number(MachineType_NUM)-1] for the
340            // component network
341            if (link_is_shortest_path_to_node(src, next, d + max_machines,
342                    weights, dist)) {
343                MachineID mach = {(MachineType)m, i};
344                result.add(mach);
345            }
346            d++;
347        }
348    }
349
350    DPRINTF(RubyNetwork, "Returning shortest path\n"
351            "(src-(2*max_machines)): %d, (next-(2*max_machines)): %d, "
352            "src: %d, next: %d, result: %s\n",
353            (src-(2*max_machines)), (next-(2*max_machines)),
354            src, next, result);
355
356    return result;
357}
358
359Topology *
360TopologyParams::create()
361{
362    return new Topology(this);
363}
364
365