PerfectSwitch.cc revision 7054:7d6862b80049 
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 "mem/gems_common/util.hh"
30#include "mem/protocol/Protocol.hh"
31#include "mem/ruby/buffers/MessageBuffer.hh"
32#include "mem/ruby/network/simple/PerfectSwitch.hh"
33#include "mem/ruby/network/simple/SimpleNetwork.hh"
34#include "mem/ruby/profiler/Profiler.hh"
35#include "mem/ruby/slicc_interface/NetworkMessage.hh"
36#include "mem/ruby/system/System.hh"
37
38const int PRIORITY_SWITCH_LIMIT = 128;
39
40// Operator for helper class
41bool
42operator<(const LinkOrder& l1, const LinkOrder& l2)
43{
44    return (l1.m_value < l2.m_value);
45}
46
47PerfectSwitch::PerfectSwitch(SwitchID sid, SimpleNetwork* network_ptr)
48{
49    m_virtual_networks = network_ptr->getNumberOfVirtualNetworks();
50    m_switch_id = sid;
51    m_round_robin_start = 0;
52    m_network_ptr = network_ptr;
53    m_wakeups_wo_switch = 0;
54}
55
56void
57PerfectSwitch::addInPort(const Vector<MessageBuffer*>& in)
58{
59    assert(in.size() == m_virtual_networks);
60    NodeID port = m_in.size();
61    m_in.insertAtBottom(in);
62    for (int j = 0; j < m_virtual_networks; j++) {
63        m_in[port][j]->setConsumer(this);
64        string desc = csprintf("[Queue from port %s %s %s to PerfectSwitch]",
65            NodeIDToString(m_switch_id), NodeIDToString(port),
66            NodeIDToString(j));
67        m_in[port][j]->setDescription(desc);
68    }
69}
70
71void
72PerfectSwitch::addOutPort(const Vector<MessageBuffer*>& out,
73    const NetDest& routing_table_entry)
74{
75    assert(out.size() == m_virtual_networks);
76
77    // Setup link order
78    LinkOrder l;
79    l.m_value = 0;
80    l.m_link = m_out.size();
81    m_link_order.insertAtBottom(l);
82
83    // Add to routing table
84    m_out.insertAtBottom(out);
85    m_routing_table.insertAtBottom(routing_table_entry);
86}
87
88void
89PerfectSwitch::clearRoutingTables()
90{
91    m_routing_table.clear();
92}
93
94void
95PerfectSwitch::clearBuffers()
96{
97    for (int i = 0; i < m_in.size(); i++){
98        for(int vnet = 0; vnet < m_virtual_networks; vnet++) {
99            m_in[i][vnet]->clear();
100        }
101    }
102
103    for (int i = 0; i < m_out.size(); i++){
104        for(int vnet = 0; vnet < m_virtual_networks; vnet++) {
105            m_out[i][vnet]->clear();
106        }
107    }
108}
109
110void
111PerfectSwitch::reconfigureOutPort(const NetDest& routing_table_entry)
112{
113    m_routing_table.insertAtBottom(routing_table_entry);
114}
115
116PerfectSwitch::~PerfectSwitch()
117{
118}
119
120void
121PerfectSwitch::wakeup()
122{
123    DEBUG_EXPR(NETWORK_COMP, MedPrio, m_switch_id);
124
125    MsgPtr msg_ptr;
126
127    // Give the highest numbered link priority most of the time
128    m_wakeups_wo_switch++;
129    int highest_prio_vnet = m_virtual_networks-1;
130    int lowest_prio_vnet = 0;
131    int decrementer = 1;
132    NetworkMessage* net_msg_ptr = NULL;
133
134    // invert priorities to avoid starvation seen in the component network
135    if (m_wakeups_wo_switch > PRIORITY_SWITCH_LIMIT) {
136        m_wakeups_wo_switch = 0;
137        highest_prio_vnet = 0;
138        lowest_prio_vnet = m_virtual_networks-1;
139        decrementer = -1;
140    }
141
142    // For all components incoming queues
143    for (int vnet = highest_prio_vnet;
144         (vnet * decrementer) >= (decrementer * lowest_prio_vnet);
145         vnet -= decrementer) {
146
147        // This is for round-robin scheduling
148        int incoming = m_round_robin_start;
149        m_round_robin_start++;
150        if (m_round_robin_start >= m_in.size()) {
151            m_round_robin_start = 0;
152        }
153
154        // for all input ports, use round robin scheduling
155        for (int counter = 0; counter < m_in.size(); counter++) {
156            // Round robin scheduling
157            incoming++;
158            if (incoming >= m_in.size()) {
159                incoming = 0;
160            }
161
162            // temporary vectors to store the routing results
163            Vector<LinkID> output_links;
164            Vector<NetDest> output_link_destinations;
165
166            // Is there a message waiting?
167            while (m_in[incoming][vnet]->isReady()) {
168                DEBUG_EXPR(NETWORK_COMP, MedPrio, incoming);
169
170                // Peek at message
171                msg_ptr = m_in[incoming][vnet]->peekMsgPtr();
172                net_msg_ptr = dynamic_cast<NetworkMessage*>(msg_ptr.ref());
173                DEBUG_EXPR(NETWORK_COMP, MedPrio, *net_msg_ptr);
174
175                output_links.clear();
176                output_link_destinations.clear();
177                NetDest msg_dsts =
178                    net_msg_ptr->getInternalDestination();
179
180                // Unfortunately, the token-protocol sends some
181                // zero-destination messages, so this assert isn't valid
182                // assert(msg_dsts.count() > 0);
183
184                assert(m_link_order.size() == m_routing_table.size());
185                assert(m_link_order.size() == m_out.size());
186
187                if (m_network_ptr->getAdaptiveRouting()) {
188                    if (m_network_ptr->isVNetOrdered(vnet)) {
189                        // Don't adaptively route
190                        for (int out = 0; out < m_out.size(); out++) {
191                            m_link_order[out].m_link = out;
192                            m_link_order[out].m_value = 0;
193                        }
194                    } else {
195                        // Find how clogged each link is
196                        for (int out = 0; out < m_out.size(); out++) {
197                            int out_queue_length = 0;
198                            for (int v = 0; v < m_virtual_networks; v++) {
199                                out_queue_length += m_out[out][v]->getSize();
200                            }
201                            int value =
202                                (out_queue_length << 8) | (random() & 0xff);
203                            m_link_order[out].m_link = out;
204                            m_link_order[out].m_value = value;
205                        }
206
207                        // Look at the most empty link first
208                        m_link_order.sortVector();
209                    }
210                }
211
212                for (int i = 0; i < m_routing_table.size(); i++) {
213                    // pick the next link to look at
214                    int link = m_link_order[i].m_link;
215                    NetDest dst = m_routing_table[link];
216                    DEBUG_EXPR(NETWORK_COMP, MedPrio, dst);
217
218                    if (!msg_dsts.intersectionIsNotEmpty(dst))
219                        continue;
220
221                    // Remember what link we're using
222                    output_links.insertAtBottom(link);
223
224                    // Need to remember which destinations need this
225                    // message in another vector.  This Set is the
226                    // intersection of the routing_table entry and the
227                    // current destination set.  The intersection must
228                    // not be empty, since we are inside "if"
229                    output_link_destinations.insertAtBottom(msg_dsts.AND(dst));
230
231                    // Next, we update the msg_destination not to
232                    // include those nodes that were already handled
233                    // by this link
234                    msg_dsts.removeNetDest(dst);
235                }
236
237                assert(msg_dsts.count() == 0);
238                //assert(output_links.size() > 0);
239
240                // Check for resources - for all outgoing queues
241                bool enough = true;
242                for (int i = 0; i < output_links.size(); i++) {
243                    int outgoing = output_links[i];
244                    if (!m_out[outgoing][vnet]->areNSlotsAvailable(1))
245                        enough = false;
246                    DEBUG_MSG(NETWORK_COMP, HighPrio,
247                        "checking if node is blocked");
248                    DEBUG_EXPR(NETWORK_COMP, HighPrio, outgoing);
249                    DEBUG_EXPR(NETWORK_COMP, HighPrio, vnet);
250                    DEBUG_EXPR(NETWORK_COMP, HighPrio, enough);
251                }
252
253                // There were not enough resources
254                if (!enough) {
255                    g_eventQueue_ptr->scheduleEvent(this, 1);
256                    DEBUG_MSG(NETWORK_COMP, HighPrio,
257                        "Can't deliver message since a node is blocked");
258                    DEBUG_EXPR(NETWORK_COMP, HighPrio, *net_msg_ptr);
259                    break; // go to next incoming port
260                }
261
262                MsgPtr unmodified_msg_ptr;
263
264                if (output_links.size() > 1) {
265                    // If we are sending this message down more than
266                    // one link (size>1), we need to make a copy of
267                    // the message so each branch can have a different
268                    // internal destination we need to create an
269                    // unmodified MsgPtr because the MessageBuffer
270                    // enqueue func will modify the message
271
272                    // This magic line creates a private copy of the
273                    // message
274                    unmodified_msg_ptr = *(msg_ptr.ref());
275                }
276
277                // Enqueue it - for all outgoing queues
278                for (int i=0; i<output_links.size(); i++) {
279                    int outgoing = output_links[i];
280
281                    if (i > 0) {
282                        // create a private copy of the unmodified
283                        // message
284                        msg_ptr = *(unmodified_msg_ptr.ref());
285                    }
286
287                    // Change the internal destination set of the
288                    // message so it knows which destinations this
289                    // link is responsible for.
290                    net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.ref());
291                    net_msg_ptr->getInternalDestination() =
292                        output_link_destinations[i];
293
294                    // Enqeue msg
295                    DEBUG_NEWLINE(NETWORK_COMP,HighPrio);
296                    DEBUG_MSG(NETWORK_COMP, HighPrio,
297                        csprintf("switch: %d enqueuing net msg from "
298                            "inport[%d][%d] to outport [%d][%d] time: %d.",
299                            m_switch_id, incoming, vnet, outgoing, vnet,
300                            g_eventQueue_ptr->getTime()));
301                    DEBUG_NEWLINE(NETWORK_COMP,HighPrio);
302
303                    m_out[outgoing][vnet]->enqueue(msg_ptr);
304                }
305
306                // Dequeue msg
307                m_in[incoming][vnet]->pop();
308            }
309        }
310    }
311}
312
313void
314PerfectSwitch::printStats(std::ostream& out) const
315{
316    out << "PerfectSwitch printStats" << endl;
317}
318
319void
320PerfectSwitch::clearStats()
321{
322}
323
324void
325PerfectSwitch::printConfig(std::ostream& out) const
326{
327}
328
329void
330PerfectSwitch::print(std::ostream& out) const
331{
332    out << "[PerfectSwitch " << m_switch_id << "]";
333}
334
335