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/ruby/network/simple/Throttle.hh"
30
31#include <cassert>
32
33#include "base/cast.hh"
34#include "base/cprintf.hh"
35#include "debug/RubyNetwork.hh"
36#include "mem/ruby/network/MessageBuffer.hh"
37#include "mem/ruby/network/Network.hh"
38#include "mem/ruby/network/simple/Switch.hh"
39#include "mem/ruby/slicc_interface/Message.hh"
40#include "mem/ruby/system/RubySystem.hh"
41
42using namespace std;
43
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(Message* net_msg_ptr);
50
51Throttle::Throttle(int sID, RubySystem *rs, NodeID node, Cycles link_latency,
52                   int link_bandwidth_multiplier, int endpoint_bandwidth,
53                   Switch *em)
54    : Consumer(em), m_switch_id(sID), m_switch(em), m_node(node),
55      m_ruby_system(rs)
56{
57    m_vnets = 0;
58
59    assert(link_bandwidth_multiplier > 0);
60    m_link_bandwidth_multiplier = link_bandwidth_multiplier;
61
62    m_link_latency = link_latency;
63    m_endpoint_bandwidth = endpoint_bandwidth;
64
65    m_wakeups_wo_switch = 0;
66    m_link_utilization_proxy = 0;
67}
68
69void
70Throttle::addLinks(const vector<MessageBuffer*>& in_vec,
71                   const vector<MessageBuffer*>& out_vec)
72{
73    assert(in_vec.size() == out_vec.size());
74
75    for (int vnet = 0; vnet < in_vec.size(); ++vnet) {
76        MessageBuffer *in_ptr = in_vec[vnet];
77        MessageBuffer *out_ptr = out_vec[vnet];
78
79        m_vnets++;
80        m_units_remaining.push_back(0);
81        m_in.push_back(in_ptr);
82        m_out.push_back(out_ptr);
83
84        // Set consumer and description
85        in_ptr->setConsumer(this);
86        string desc = "[Queue to Throttle " + to_string(m_switch_id) + " " +
87            to_string(m_node) + "]";
88    }
89}
90
91void
92Throttle::operateVnet(int vnet, int &bw_remaining, bool &schedule_wakeup,
93                      MessageBuffer *in, MessageBuffer *out)
94{
95    if (out == nullptr || in == nullptr) {
96        return;
97    }
98
99    assert(m_units_remaining[vnet] >= 0);
100    Tick current_time = m_switch->clockEdge();
101
102    while (bw_remaining > 0 && (in->isReady(current_time) ||
103                                m_units_remaining[vnet] > 0) &&
104           out->areNSlotsAvailable(1, current_time)) {
105        // See if we are done transferring the previous message on
106        // this virtual network
107        if (m_units_remaining[vnet] == 0 && in->isReady(current_time)) {
108            // Find the size of the message we are moving
109            MsgPtr msg_ptr = in->peekMsgPtr();
110            Message *net_msg_ptr = msg_ptr.get();
111            m_units_remaining[vnet] +=
112                network_message_to_size(net_msg_ptr);
113
114            DPRINTF(RubyNetwork, "throttle: %d my bw %d bw spent "
115                    "enqueueing net msg %d time: %lld.\n",
116                    m_node, getLinkBandwidth(), m_units_remaining[vnet],
117                    m_ruby_system->curCycle());
118
119            // Move the message
120            in->dequeue(current_time);
121            out->enqueue(msg_ptr, current_time,
122                         m_switch->cyclesToTicks(m_link_latency));
123
124            // Count the message
125            m_msg_counts[net_msg_ptr->getMessageSize()][vnet]++;
126            DPRINTF(RubyNetwork, "%s\n", *out);
127        }
128
129        // Calculate the amount of bandwidth we spent on this message
130        int diff = m_units_remaining[vnet] - bw_remaining;
131        m_units_remaining[vnet] = max(0, diff);
132        bw_remaining = max(0, -diff);
133    }
134
135    if (bw_remaining > 0 && (in->isReady(current_time) ||
136                             m_units_remaining[vnet] > 0) &&
137        !out->areNSlotsAvailable(1, current_time)) {
138        DPRINTF(RubyNetwork, "vnet: %d", vnet);
139
140        // schedule me to wakeup again because I'm waiting for my
141        // output queue to become available
142        schedule_wakeup = true;
143    }
144}
145
146void
147Throttle::wakeup()
148{
149    // Limits the number of message sent to a limited number of bytes/cycle.
150    assert(getLinkBandwidth() > 0);
151    int bw_remaining = getLinkBandwidth();
152
153    m_wakeups_wo_switch++;
154    bool schedule_wakeup = false;
155
156    // variable for deciding the direction in which to iterate
157    bool iteration_direction = false;
158
159
160    // invert priorities to avoid starvation seen in the component network
161    if (m_wakeups_wo_switch > PRIORITY_SWITCH_LIMIT) {
162        m_wakeups_wo_switch = 0;
163        iteration_direction = true;
164    }
165
166    if (iteration_direction) {
167        for (int vnet = 0; vnet < m_vnets; ++vnet) {
168            operateVnet(vnet, bw_remaining, schedule_wakeup,
169                        m_in[vnet], m_out[vnet]);
170        }
171    } else {
172        for (int vnet = m_vnets-1; vnet >= 0; --vnet) {
173            operateVnet(vnet, bw_remaining, schedule_wakeup,
174                        m_in[vnet], m_out[vnet]);
175        }
176    }
177
178    // We should only wake up when we use the bandwidth
179    // This is only mostly true
180    // assert(bw_remaining != getLinkBandwidth());
181
182    // Record that we used some or all of the link bandwidth this cycle
183    double ratio = 1.0 - (double(bw_remaining) / double(getLinkBandwidth()));
184
185    // If ratio = 0, we used no bandwidth, if ratio = 1, we used all
186    m_link_utilization_proxy += ratio;
187
188    if (bw_remaining > 0 && !schedule_wakeup) {
189        // We have extra bandwidth and our output buffer was
190        // available, so we must not have anything else to do until
191        // another message arrives.
192        DPRINTF(RubyNetwork, "%s not scheduled again\n", *this);
193    } else {
194        DPRINTF(RubyNetwork, "%s scheduled again\n", *this);
195
196        // We are out of bandwidth for this cycle, so wakeup next
197        // cycle and continue
198        scheduleEvent(Cycles(1));
199    }
200}
201
202void
203Throttle::regStats(string parent)
204{
205    m_link_utilization
206        .name(parent + csprintf(".throttle%i", m_node) + ".link_utilization");
207
208    for (MessageSizeType type = MessageSizeType_FIRST;
209         type < MessageSizeType_NUM; ++type) {
210        m_msg_counts[(unsigned int)type]
211            .init(Network::getNumberOfVirtualNetworks())
212            .name(parent + csprintf(".throttle%i", m_node) + ".msg_count." +
213                    MessageSizeType_to_string(type))
214            .flags(Stats::nozero)
215            ;
216        m_msg_bytes[(unsigned int) type]
217            .name(parent + csprintf(".throttle%i", m_node) + ".msg_bytes." +
218                    MessageSizeType_to_string(type))
219            .flags(Stats::nozero)
220            ;
221
222        m_msg_bytes[(unsigned int) type] = m_msg_counts[type] * Stats::constant(
223                Network::MessageSizeType_to_int(type));
224    }
225}
226
227void
228Throttle::clearStats()
229{
230    m_link_utilization_proxy = 0;
231}
232
233void
234Throttle::collateStats()
235{
236    double time_delta = double(m_ruby_system->curCycle() -
237                               m_ruby_system->getStartCycle());
238
239    m_link_utilization = 100.0 * m_link_utilization_proxy / time_delta;
240}
241
242void
243Throttle::print(ostream& out) const
244{
245    ccprintf(out,  "[%i bw: %i]", m_node, getLinkBandwidth());
246}
247
248int
249network_message_to_size(Message *net_msg_ptr)
250{
251    assert(net_msg_ptr != NULL);
252
253    int size = Network::MessageSizeType_to_int(net_msg_ptr->getMessageSize());
254    size *=  MESSAGE_SIZE_MULTIPLIER;
255
256    // Artificially increase the size of broadcast messages
257    if (BROADCAST_SCALING > 1 && net_msg_ptr->getDestination().isBroadcast())
258        size *= BROADCAST_SCALING;
259
260    return size;
261}
262