WireBuffer.cc revision 11793:ef606668d247 
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 "mem/ruby/structures/WireBuffer.hh"
33
34#include <algorithm>
35#include <functional>
36
37#include "base/cprintf.hh"
38#include "base/stl_helpers.hh"
39#include "mem/ruby/system/RubySystem.hh"
40
41using namespace std;
42
43// Output operator definition
44
45ostream&
46operator<<(ostream& out, const WireBuffer& obj)
47{
48    obj.print(out);
49    out << flush;
50    return out;
51}
52
53
54// ****************************************************************
55
56// CONSTRUCTOR
57WireBuffer::WireBuffer(const Params *p)
58    : SimObject(p)
59{
60    m_msg_counter = 0;
61}
62
63void
64WireBuffer::init()
65{
66}
67
68WireBuffer::~WireBuffer()
69{
70}
71
72void
73WireBuffer::enqueue(MsgPtr message, Tick current_time, Tick delta)
74{
75    m_msg_counter++;
76    Tick arrival_time = current_time + delta;
77    assert(arrival_time > current_time);
78
79    Message* msg_ptr = message.get();
80    msg_ptr->setLastEnqueueTime(arrival_time);
81    m_message_queue.push_back(message);
82    if (m_consumer_ptr != NULL) {
83        m_consumer_ptr->
84            scheduleEventAbsolute(arrival_time);
85    } else {
86        panic("No Consumer for WireBuffer! %s\n", *this);
87    }
88}
89
90void
91WireBuffer::dequeue(Tick current_time)
92{
93    assert(isReady(current_time));
94    pop_heap(m_message_queue.begin(), m_message_queue.end(),
95        greater<MsgPtr>());
96    m_message_queue.pop_back();
97}
98
99const Message*
100WireBuffer::peek()
101{
102    Message* msg_ptr = m_message_queue.front().get();
103    assert(msg_ptr != NULL);
104    return msg_ptr;
105}
106
107void
108WireBuffer::recycle(Tick current_time, Tick recycle_latency)
109{
110    // Because you don't want anything reordered, make sure the recycle latency
111    // is just 1 cycle. As a result, you really want to use this only in
112    // Wire-like situations because you don't want to deadlock as a result of
113    // being stuck behind something if you're not actually supposed to.
114    assert(isReady(current_time));
115    MsgPtr node = m_message_queue.front();
116    pop_heap(m_message_queue.begin(), m_message_queue.end(), greater<MsgPtr>());
117
118    Tick future_time = current_time + recycle_latency;
119    node->setLastEnqueueTime(future_time);
120
121    m_message_queue.back() = node;
122    push_heap(m_message_queue.begin(), m_message_queue.end(),
123        greater<MsgPtr>());
124    m_consumer_ptr->
125        scheduleEventAbsolute(future_time);
126}
127
128bool
129WireBuffer::isReady(Tick current_time)
130{
131    return ((!m_message_queue.empty()) &&
132            (m_message_queue.front()->getLastEnqueueTime() <= current_time));
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