Throttle.cc revision 9863 
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/cast.hh"
32#include "base/cprintf.hh"
33#include "debug/RubyNetwork.hh"
34#include "mem/ruby/buffers/MessageBuffer.hh"
35#include "mem/ruby/network/simple/Throttle.hh"
36#include "mem/ruby/network/Network.hh"
37#include "mem/ruby/slicc_interface/NetworkMessage.hh"
38#include "mem/ruby/system/System.hh"
39
40using namespace std;
41
42const int HIGH_RANGE = 256;
43const int ADJUST_INTERVAL = 50000;
44const int MESSAGE_SIZE_MULTIPLIER = 1000;
45//const int BROADCAST_SCALING = 4; // Have a 16p system act like a 64p systems
46const int BROADCAST_SCALING = 1;
47const int PRIORITY_SWITCH_LIMIT = 128;
48
49static int network_message_to_size(NetworkMessage* net_msg_ptr);
50
51Throttle::Throttle(int sID, NodeID node, Cycles link_latency,
52                   int link_bandwidth_multiplier, int endpoint_bandwidth,
53                   ClockedObject *em)
54    : Consumer(em)
55{
56    init(node, link_latency, link_bandwidth_multiplier, endpoint_bandwidth);
57    m_sID = sID;
58}
59
60Throttle::Throttle(NodeID node, Cycles link_latency,
61                   int link_bandwidth_multiplier, int endpoint_bandwidth,
62                   ClockedObject *em)
63    : Consumer(em)
64{
65    init(node, link_latency, link_bandwidth_multiplier, endpoint_bandwidth);
66    m_sID = 0;
67}
68
69void
70Throttle::init(NodeID node, Cycles link_latency,
71               int link_bandwidth_multiplier, int endpoint_bandwidth)
72{
73    m_node = node;
74    m_vnets = 0;
75
76    assert(link_bandwidth_multiplier > 0);
77    m_link_bandwidth_multiplier = link_bandwidth_multiplier;
78    m_link_latency = link_latency;
79    m_endpoint_bandwidth = endpoint_bandwidth;
80
81    m_wakeups_wo_switch = 0;
82
83    m_msg_counts.resize(MessageSizeType_NUM);
84    m_msg_bytes.resize(MessageSizeType_NUM);
85
86    m_link_utilization_proxy = 0;
87}
88
89void
90Throttle::addLinks(const std::vector<MessageBuffer*>& in_vec,
91    const std::vector<MessageBuffer*>& out_vec)
92{
93    assert(in_vec.size() == out_vec.size());
94    for (int i=0; i<in_vec.size(); i++) {
95        addVirtualNetwork(in_vec[i], out_vec[i]);
96    }
97}
98
99void
100Throttle::addVirtualNetwork(MessageBuffer* in_ptr, MessageBuffer* out_ptr)
101{
102    m_units_remaining.push_back(0);
103    m_in.push_back(in_ptr);
104    m_out.push_back(out_ptr);
105
106    // Set consumer and description
107    m_in[m_vnets]->setConsumer(this);
108
109    string desc = "[Queue to Throttle " + to_string(m_sID) + " " +
110        to_string(m_node) + "]";
111    m_in[m_vnets]->setDescription(desc);
112    m_vnets++;
113}
114
115void
116Throttle::wakeup()
117{
118    // Limits the number of message sent to a limited number of bytes/cycle.
119    assert(getLinkBandwidth() > 0);
120    int bw_remaining = getLinkBandwidth();
121
122    // Give the highest numbered link priority most of the time
123    m_wakeups_wo_switch++;
124    int highest_prio_vnet = m_vnets-1;
125    int lowest_prio_vnet = 0;
126    int counter = 1;
127    bool schedule_wakeup = false;
128
129    // invert priorities to avoid starvation seen in the component network
130    if (m_wakeups_wo_switch > PRIORITY_SWITCH_LIMIT) {
131        m_wakeups_wo_switch = 0;
132        highest_prio_vnet = 0;
133        lowest_prio_vnet = m_vnets-1;
134        counter = -1;
135    }
136
137    for (int vnet = highest_prio_vnet;
138         (vnet * counter) >= (counter * lowest_prio_vnet);
139         vnet -= counter) {
140
141        assert(m_out[vnet] != NULL);
142        assert(m_in[vnet] != NULL);
143        assert(m_units_remaining[vnet] >= 0);
144
145        while (bw_remaining > 0 &&
146            (m_in[vnet]->isReady() || m_units_remaining[vnet] > 0) &&
147            m_out[vnet]->areNSlotsAvailable(1)) {
148
149            // See if we are done transferring the previous message on
150            // this virtual network
151            if (m_units_remaining[vnet] == 0 && m_in[vnet]->isReady()) {
152                // Find the size of the message we are moving
153                MsgPtr msg_ptr = m_in[vnet]->peekMsgPtr();
154                NetworkMessage* net_msg_ptr =
155                    safe_cast<NetworkMessage*>(msg_ptr.get());
156                m_units_remaining[vnet] +=
157                    network_message_to_size(net_msg_ptr);
158
159                DPRINTF(RubyNetwork, "throttle: %d my bw %d bw spent "
160                        "enqueueing net msg %d time: %lld.\n",
161                        m_node, getLinkBandwidth(), m_units_remaining[vnet],
162                        g_system_ptr->curCycle());
163
164                // Move the message
165                m_out[vnet]->enqueue(m_in[vnet]->peekMsgPtr(), m_link_latency);
166                m_in[vnet]->pop();
167
168                // Count the message
169                m_msg_counts[net_msg_ptr->getMessageSize()][vnet]++;
170
171                DPRINTF(RubyNetwork, "%s\n", *m_out[vnet]);
172            }
173
174            // Calculate the amount of bandwidth we spent on this message
175            int diff = m_units_remaining[vnet] - bw_remaining;
176            m_units_remaining[vnet] = max(0, diff);
177            bw_remaining = max(0, -diff);
178        }
179
180        if (bw_remaining > 0 &&
181            (m_in[vnet]->isReady() || m_units_remaining[vnet] > 0) &&
182            !m_out[vnet]->areNSlotsAvailable(1)) {
183            DPRINTF(RubyNetwork, "vnet: %d", vnet);
184            // schedule me to wakeup again because I'm waiting for my
185            // output queue to become available
186            schedule_wakeup = true;
187        }
188    }
189
190    // We should only wake up when we use the bandwidth
191    // This is only mostly true
192    // assert(bw_remaining != getLinkBandwidth());
193
194    // Record that we used some or all of the link bandwidth this cycle
195    double ratio = 1.0 - (double(bw_remaining) / double(getLinkBandwidth()));
196
197    // If ratio = 0, we used no bandwidth, if ratio = 1, we used all
198    m_link_utilization_proxy += ratio;
199
200    if (bw_remaining > 0 && !schedule_wakeup) {
201        // We have extra bandwidth and our output buffer was
202        // available, so we must not have anything else to do until
203        // another message arrives.
204        DPRINTF(RubyNetwork, "%s not scheduled again\n", *this);
205    } else {
206        DPRINTF(RubyNetwork, "%s scheduled again\n", *this);
207
208        // We are out of bandwidth for this cycle, so wakeup next
209        // cycle and continue
210        scheduleEvent(Cycles(1));
211    }
212}
213
214void
215Throttle::regStats(string parent)
216{
217    m_link_utilization
218        .name(parent + csprintf(".throttle%i", m_node) + ".link_utilization");
219
220    for (MessageSizeType type = MessageSizeType_FIRST;
221         type < MessageSizeType_NUM; ++type) {
222        m_msg_counts[(unsigned int)type]
223            .init(m_vnets)
224            .name(parent + csprintf(".throttle%i", m_node) + ".msg_count." +
225                    MessageSizeType_to_string(type))
226            .flags(Stats::nozero)
227            ;
228        m_msg_bytes[(unsigned int) type]
229            .name(parent + csprintf(".throttle%i", m_node) + ".msg_bytes." +
230                    MessageSizeType_to_string(type))
231            .flags(Stats::nozero)
232            ;
233
234        m_msg_bytes[(unsigned int) type] = m_msg_counts[type] * Stats::constant(
235                Network::MessageSizeType_to_int(type));
236    }
237}
238
239void
240Throttle::clearStats()
241{
242    m_link_utilization_proxy = 0;
243}
244
245void
246Throttle::collateStats()
247{
248    m_link_utilization = 100.0 * m_link_utilization_proxy
249        / (double(g_system_ptr->curCycle() - g_ruby_start));
250}
251
252void
253Throttle::print(ostream& out) const
254{
255    ccprintf(out,  "[%i bw: %i]", m_node, getLinkBandwidth());
256}
257
258int
259network_message_to_size(NetworkMessage* net_msg_ptr)
260{
261    assert(net_msg_ptr != NULL);
262
263    int size = Network::MessageSizeType_to_int(net_msg_ptr->getMessageSize());
264    size *=  MESSAGE_SIZE_MULTIPLIER;
265
266    // Artificially increase the size of broadcast messages
267    if (BROADCAST_SCALING > 1 && net_msg_ptr->getDestination().isBroadcast())
268        size *= BROADCAST_SCALING;
269
270    return size;
271}
272