Throttle.cc revision 11111 
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/network/simple/Switch.hh"
35#include "mem/ruby/network/simple/Throttle.hh"
36#include "mem/ruby/network/MessageBuffer.hh"
37#include "mem/ruby/network/Network.hh"
38#include "mem/ruby/slicc_interface/Message.hh"
39#include "mem/ruby/system/RubySystem.hh"
40
41using namespace std;
42
43const int MESSAGE_SIZE_MULTIPLIER = 1000;
44//const int BROADCAST_SCALING = 4; // Have a 16p system act like a 64p systems
45const int BROADCAST_SCALING = 1;
46const int PRIORITY_SWITCH_LIMIT = 128;
47
48static int network_message_to_size(Message* net_msg_ptr);
49
50Throttle::Throttle(int sID, RubySystem *rs, NodeID node, Cycles link_latency,
51                   int link_bandwidth_multiplier, int endpoint_bandwidth,
52                   Switch *em)
53    : Consumer(em), m_switch_id(sID), m_switch(em), m_node(node),
54      m_ruby_system(rs)
55{
56    m_vnets = 0;
57
58    assert(link_bandwidth_multiplier > 0);
59    m_link_bandwidth_multiplier = link_bandwidth_multiplier;
60
61    m_link_latency = link_latency;
62    m_endpoint_bandwidth = endpoint_bandwidth;
63
64    m_wakeups_wo_switch = 0;
65    m_link_utilization_proxy = 0;
66}
67
68void
69Throttle::addLinks(const vector<MessageBuffer*>& in_vec,
70                   const vector<MessageBuffer*>& out_vec)
71{
72    assert(in_vec.size() == out_vec.size());
73
74    for (int vnet = 0; vnet < in_vec.size(); ++vnet) {
75        MessageBuffer *in_ptr = in_vec[vnet];
76        MessageBuffer *out_ptr = out_vec[vnet];
77
78        m_vnets++;
79        m_units_remaining.push_back(0);
80        m_in.push_back(in_ptr);
81        m_out.push_back(out_ptr);
82
83        // Set consumer and description
84        in_ptr->setConsumer(this);
85        string desc = "[Queue to Throttle " + to_string(m_switch_id) + " " +
86            to_string(m_node) + "]";
87    }
88}
89
90void
91Throttle::operateVnet(int vnet, int &bw_remaining, bool &schedule_wakeup,
92                      MessageBuffer *in, MessageBuffer *out)
93{
94    if (out == nullptr || in == nullptr) {
95        return;
96    }
97
98    assert(m_units_remaining[vnet] >= 0);
99    Tick current_time = m_switch->clockEdge();
100
101    while (bw_remaining > 0 && (in->isReady(current_time) ||
102                                m_units_remaining[vnet] > 0) &&
103           out->areNSlotsAvailable(1, current_time)) {
104        // See if we are done transferring the previous message on
105        // this virtual network
106        if (m_units_remaining[vnet] == 0 && in->isReady(current_time)) {
107            // Find the size of the message we are moving
108            MsgPtr msg_ptr = in->peekMsgPtr();
109            Message *net_msg_ptr = msg_ptr.get();
110            m_units_remaining[vnet] +=
111                network_message_to_size(net_msg_ptr);
112
113            DPRINTF(RubyNetwork, "throttle: %d my bw %d bw spent "
114                    "enqueueing net msg %d time: %lld.\n",
115                    m_node, getLinkBandwidth(), m_units_remaining[vnet],
116                    m_ruby_system->curCycle());
117
118            // Move the message
119            in->dequeue(current_time);
120            out->enqueue(msg_ptr, current_time,
121                         m_switch->cyclesToTicks(m_link_latency));
122
123            // Count the message
124            m_msg_counts[net_msg_ptr->getMessageSize()][vnet]++;
125            DPRINTF(RubyNetwork, "%s\n", *out);
126        }
127
128        // Calculate the amount of bandwidth we spent on this message
129        int diff = m_units_remaining[vnet] - bw_remaining;
130        m_units_remaining[vnet] = max(0, diff);
131        bw_remaining = max(0, -diff);
132    }
133
134    if (bw_remaining > 0 && (in->isReady(current_time) ||
135                             m_units_remaining[vnet] > 0) &&
136        !out->areNSlotsAvailable(1, current_time)) {
137        DPRINTF(RubyNetwork, "vnet: %d", vnet);
138
139        // schedule me to wakeup again because I'm waiting for my
140        // output queue to become available
141        schedule_wakeup = true;
142    }
143}
144
145void
146Throttle::wakeup()
147{
148    // Limits the number of message sent to a limited number of bytes/cycle.
149    assert(getLinkBandwidth() > 0);
150    int bw_remaining = getLinkBandwidth();
151
152    m_wakeups_wo_switch++;
153    bool schedule_wakeup = false;
154
155    // variable for deciding the direction in which to iterate
156    bool iteration_direction = false;
157
158
159    // invert priorities to avoid starvation seen in the component network
160    if (m_wakeups_wo_switch > PRIORITY_SWITCH_LIMIT) {
161        m_wakeups_wo_switch = 0;
162        iteration_direction = true;
163    }
164
165    if (iteration_direction) {
166        for (int vnet = 0; vnet < m_vnets; ++vnet) {
167            operateVnet(vnet, bw_remaining, schedule_wakeup,
168                        m_in[vnet], m_out[vnet]);
169        }
170    } else {
171        for (int vnet = m_vnets-1; vnet >= 0; --vnet) {
172            operateVnet(vnet, bw_remaining, schedule_wakeup,
173                        m_in[vnet], m_out[vnet]);
174        }
175    }
176
177    // We should only wake up when we use the bandwidth
178    // This is only mostly true
179    // assert(bw_remaining != getLinkBandwidth());
180
181    // Record that we used some or all of the link bandwidth this cycle
182    double ratio = 1.0 - (double(bw_remaining) / double(getLinkBandwidth()));
183
184    // If ratio = 0, we used no bandwidth, if ratio = 1, we used all
185    m_link_utilization_proxy += ratio;
186
187    if (bw_remaining > 0 && !schedule_wakeup) {
188        // We have extra bandwidth and our output buffer was
189        // available, so we must not have anything else to do until
190        // another message arrives.
191        DPRINTF(RubyNetwork, "%s not scheduled again\n", *this);
192    } else {
193        DPRINTF(RubyNetwork, "%s scheduled again\n", *this);
194
195        // We are out of bandwidth for this cycle, so wakeup next
196        // cycle and continue
197        scheduleEvent(Cycles(1));
198    }
199}
200
201void
202Throttle::regStats(string parent)
203{
204    m_link_utilization
205        .name(parent + csprintf(".throttle%i", m_node) + ".link_utilization");
206
207    for (MessageSizeType type = MessageSizeType_FIRST;
208         type < MessageSizeType_NUM; ++type) {
209        m_msg_counts[(unsigned int)type]
210            .init(Network::getNumberOfVirtualNetworks())
211            .name(parent + csprintf(".throttle%i", m_node) + ".msg_count." +
212                    MessageSizeType_to_string(type))
213            .flags(Stats::nozero)
214            ;
215        m_msg_bytes[(unsigned int) type]
216            .name(parent + csprintf(".throttle%i", m_node) + ".msg_bytes." +
217                    MessageSizeType_to_string(type))
218            .flags(Stats::nozero)
219            ;
220
221        m_msg_bytes[(unsigned int) type] = m_msg_counts[type] * Stats::constant(
222                Network::MessageSizeType_to_int(type));
223    }
224}
225
226void
227Throttle::clearStats()
228{
229    m_link_utilization_proxy = 0;
230}
231
232void
233Throttle::collateStats()
234{
235    double time_delta = double(m_ruby_system->curCycle() -
236                               m_ruby_system->getStartCycle());
237
238    m_link_utilization = 100.0 * m_link_utilization_proxy / time_delta;
239}
240
241void
242Throttle::print(ostream& out) const
243{
244    ccprintf(out,  "[%i bw: %i]", m_node, getLinkBandwidth());
245}
246
247int
248network_message_to_size(Message *net_msg_ptr)
249{
250    assert(net_msg_ptr != NULL);
251
252    int size = Network::MessageSizeType_to_int(net_msg_ptr->getMessageSize());
253    size *=  MESSAGE_SIZE_MULTIPLIER;
254
255    // Artificially increase the size of broadcast messages
256    if (BROADCAST_SCALING > 1 && net_msg_ptr->getDestination().isBroadcast())
257        size *= BROADCAST_SCALING;
258
259    return size;
260}
261