WireBuffer.cc revision 10919:80069a602c83 
1/*
2 * Copyright (c) 2010 Advanced Micro Devices, Inc.
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 * Author:  Lisa Hsu
29 *
30 */
31
32#include <algorithm>
33#include <functional>
34
35#include "base/cprintf.hh"
36#include "base/stl_helpers.hh"
37#include "mem/ruby/structures/WireBuffer.hh"
38#include "mem/ruby/system/System.hh"
39
40using namespace std;
41
42// Output operator definition
43
44ostream&
45operator<<(ostream& out, const WireBuffer& obj)
46{
47    obj.print(out);
48    out << flush;
49    return out;
50}
51
52
53// ****************************************************************
54
55// CONSTRUCTOR
56WireBuffer::WireBuffer(const Params *p)
57    : SimObject(p)
58{
59    m_msg_counter = 0;
60    m_ruby_system = p->ruby_system;
61}
62
63void
64WireBuffer::init()
65{
66}
67
68WireBuffer::~WireBuffer()
69{
70}
71
72void
73WireBuffer::enqueue(MsgPtr message, Cycles latency)
74{
75    m_msg_counter++;
76    Cycles current_time = m_ruby_system->curCycle();
77    Cycles arrival_time = current_time + latency;
78    assert(arrival_time > current_time);
79
80    Message* msg_ptr = message.get();
81    msg_ptr->setLastEnqueueTime(arrival_time);
82    m_message_queue.push_back(message);
83    if (m_consumer_ptr != NULL) {
84        m_consumer_ptr->
85            scheduleEventAbsolute(m_ruby_system->clockPeriod() * arrival_time);
86    } else {
87        panic("No Consumer for WireBuffer! %s\n", *this);
88    }
89}
90
91void
92WireBuffer::dequeue()
93{
94    assert(isReady());
95    pop_heap(m_message_queue.begin(), m_message_queue.end(),
96        greater<MsgPtr>());
97    m_message_queue.pop_back();
98}
99
100const Message*
101WireBuffer::peek()
102{
103    Message* msg_ptr = m_message_queue.front().get();
104    assert(msg_ptr != NULL);
105    return msg_ptr;
106}
107
108void
109WireBuffer::recycle()
110{
111    // Because you don't want anything reordered, make sure the recycle latency
112    // is just 1 cycle. As a result, you really want to use this only in
113    // Wire-like situations because you don't want to deadlock as a result of
114    // being stuck behind something if you're not actually supposed to.
115    assert(isReady());
116    MsgPtr node = m_message_queue.front();
117    pop_heap(m_message_queue.begin(), m_message_queue.end(), greater<MsgPtr>());
118
119    node->setLastEnqueueTime(m_ruby_system->curCycle() + Cycles(1));
120    m_message_queue.back() = node;
121    push_heap(m_message_queue.begin(), m_message_queue.end(),
122        greater<MsgPtr>());
123    m_consumer_ptr->
124        scheduleEventAbsolute(m_ruby_system->curCycle() + Cycles(1));
125}
126
127bool
128WireBuffer::isReady()
129{
130    return ((!m_message_queue.empty()) &&
131            (m_message_queue.front()->getLastEnqueueTime() <=
132                    m_ruby_system->curCycle()));
133}
134
135void
136WireBuffer::print(ostream& out) const
137{
138}
139
140void
141WireBuffer::wakeup()
142{
143}
144
145WireBuffer *
146RubyWireBufferParams::create()
147{
148    return new WireBuffer(this);
149}
150