PersistentTable.cc revision 7455 
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/system/PersistentTable.hh"
30
31using namespace std;
32
33// randomize so that handoffs are not locality-aware
34#if 0
35int persistent_randomize[] = {0, 4, 8, 12, 1, 5, 9, 13, 2, 6,
36                              10, 14, 3, 7, 11, 15};
37int persistent_randomize[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
38                              10, 11, 12, 13, 14, 15};
39#endif
40
41PersistentTable::PersistentTable()
42{
43}
44
45PersistentTable::~PersistentTable()
46{
47}
48
49void
50PersistentTable::persistentRequestLock(const Address& address,
51                                       MachineID locker,
52                                       AccessType type)
53{
54#if 0
55    if (locker == m_chip_ptr->getID())
56        cout << "Chip " << m_chip_ptr->getID() << ": " << llocker
57             << " requesting lock for " << address << endl;
58
59    MachineID locker = (MachineID) persistent_randomize[llocker];
60#endif
61
62    assert(address == line_address(address));
63
64    static const PersistentTableEntry dflt;
65    pair<AddressMap::iterator, bool> r =
66        m_map.insert(AddressMap::value_type(address, dflt));
67    bool present = !r.second;
68    AddressMap::iterator i = r.first;
69    PersistentTableEntry &entry = i->second;
70
71    if (present) {
72        // Make sure we're not already in the locked set
73        assert(!(entry.m_starving.isElement(locker)));
74    }
75
76    entry.m_starving.add(locker);
77    if (type == AccessType_Write)
78        entry.m_request_to_write.add(locker);
79
80    if (present)
81        assert(entry.m_marked.isSubset(entry.m_starving));
82}
83
84void
85PersistentTable::persistentRequestUnlock(const Address& address,
86                                         MachineID unlocker)
87{
88#if 0
89    if (unlocker == m_chip_ptr->getID())
90        cout << "Chip " << m_chip_ptr->getID() << ": " << uunlocker
91             << " requesting unlock for " << address << endl;
92
93    MachineID unlocker = (MachineID) persistent_randomize[uunlocker];
94#endif
95
96    assert(address == line_address(address));
97    assert(m_map.count(address));
98    PersistentTableEntry& entry = m_map[address];
99
100    //
101    // Make sure we're in the locked set
102    //
103    assert(entry.m_starving.isElement(unlocker));
104    assert(entry.m_marked.isSubset(entry.m_starving));
105    entry.m_starving.remove(unlocker);
106    entry.m_marked.remove(unlocker);
107    entry.m_request_to_write.remove(unlocker);
108    assert(entry.m_marked.isSubset(entry.m_starving));
109
110    // Deallocate if empty
111    if (entry.m_starving.isEmpty()) {
112        assert(entry.m_marked.isEmpty());
113        m_map.erase(address);
114    }
115}
116
117bool
118PersistentTable::okToIssueStarving(const Address& address,
119                                   MachineID machId) const
120{
121    assert(address == line_address(address));
122
123    AddressMap::const_iterator i = m_map.find(address);
124    if (i == m_map.end()) {
125        // No entry present
126        return true;
127    }
128
129    const PersistentTableEntry &entry = i->second;
130
131    if (entry.m_starving.isElement(machId)) {
132        // We can't issue another lockdown until are previous unlock
133        // has occurred
134        return false;
135    }
136
137    return entry.m_marked.isEmpty();
138}
139
140MachineID
141PersistentTable::findSmallest(const Address& address) const
142{
143    assert(address == line_address(address));
144    AddressMap::const_iterator i = m_map.find(address);
145    assert(i != m_map.end());
146    const PersistentTableEntry& entry = i->second;
147    return entry.m_starving.smallestElement();
148}
149
150AccessType
151PersistentTable::typeOfSmallest(const Address& address) const
152{
153    assert(address == line_address(address));
154    AddressMap::const_iterator i = m_map.find(address);
155    assert(i != m_map.end());
156    const PersistentTableEntry& entry = i->second;
157    if (entry.m_request_to_write.
158        isElement(entry.m_starving.smallestElement())) {
159        return AccessType_Write;
160    } else {
161        return AccessType_Read;
162    }
163}
164
165void
166PersistentTable::markEntries(const Address& address)
167{
168    assert(address == line_address(address));
169    AddressMap::iterator i = m_map.find(address);
170    if (i == m_map.end())
171        return;
172
173    PersistentTableEntry& entry = i->second;
174
175    // None should be marked
176    assert(entry.m_marked.isEmpty());
177
178    // Mark all the nodes currently in the table
179    entry.m_marked = entry.m_starving;
180}
181
182bool
183PersistentTable::isLocked(const Address& address) const
184{
185    assert(address == line_address(address));
186
187    // If an entry is present, it must be locked
188    return m_map.count(address) > 0;
189}
190
191int
192PersistentTable::countStarvingForAddress(const Address& address) const
193{
194    assert(address == line_address(address));
195    AddressMap::const_iterator i = m_map.find(address);
196    if (i == m_map.end())
197        return 0;
198
199    const PersistentTableEntry& entry = i->second;
200    return entry.m_starving.count();
201}
202
203int
204PersistentTable::countReadStarvingForAddress(const Address& address) const
205{
206    assert(address == line_address(address));
207    AddressMap::const_iterator i = m_map.find(address);
208    if (i == m_map.end())
209        return 0;
210
211    const PersistentTableEntry& entry = i->second;
212    return entry.m_starving.count() - entry.m_request_to_write.count();
213}
214
215void
216PersistentTable::print(ostream& out) const
217{
218}
219
220