mshr_queue.cc revision 4920 
1/*
2 * Copyright (c) 2003-2005 The Regents of The University of Michigan
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 * Authors: Erik Hallnor
29 */
30
31/** @file
32 * Definition of MSHRQueue class functions.
33 */
34
35#include "mem/cache/miss/mshr_queue.hh"
36
37using namespace std;
38
39MSHRQueue::MSHRQueue(int num_entries, int reserve, int _index)
40    : numEntries(num_entries + reserve - 1), numReserve(reserve),
41      index(_index)
42{
43    allocated = 0;
44    inServiceEntries = 0;
45    registers = new MSHR[numEntries];
46    for (int i = 0; i < numEntries; ++i) {
47        registers[i].queue = this;
48        freeList.push_back(&registers[i]);
49    }
50}
51
52MSHRQueue::~MSHRQueue()
53{
54    delete [] registers;
55}
56
57MSHR *
58MSHRQueue::findMatch(Addr addr) const
59{
60    MSHR::ConstIterator i = allocatedList.begin();
61    MSHR::ConstIterator end = allocatedList.end();
62    for (; i != end; ++i) {
63        MSHR *mshr = *i;
64        if (mshr->addr == addr) {
65            return mshr;
66        }
67    }
68    return NULL;
69}
70
71bool
72MSHRQueue::findMatches(Addr addr, vector<MSHR*>& matches) const
73{
74    // Need an empty vector
75    assert(matches.empty());
76    bool retval = false;
77    MSHR::ConstIterator i = allocatedList.begin();
78    MSHR::ConstIterator end = allocatedList.end();
79    for (; i != end; ++i) {
80        MSHR *mshr = *i;
81        if (mshr->addr == addr) {
82            retval = true;
83            matches.push_back(mshr);
84        }
85    }
86    return retval;
87}
88
89
90bool
91MSHRQueue::checkFunctional(PacketPtr pkt, Addr blk_addr)
92{
93    MSHR::ConstIterator i = allocatedList.begin();
94    MSHR::ConstIterator end = allocatedList.end();
95    for (; i != end; ++i) {
96        MSHR *mshr = *i;
97        if (mshr->addr == blk_addr && mshr->checkFunctional(pkt)) {
98            return true;
99        }
100    }
101    return false;
102}
103
104
105MSHR *
106MSHRQueue::findPending(Addr addr, int size) const
107{
108    MSHR::ConstIterator i = readyList.begin();
109    MSHR::ConstIterator end = readyList.end();
110    for (; i != end; ++i) {
111        MSHR *mshr = *i;
112        if (mshr->addr < addr) {
113            if (mshr->addr + mshr->size > addr) {
114                return mshr;
115            }
116        } else {
117            if (addr + size > mshr->addr) {
118                return mshr;
119            }
120        }
121    }
122    return NULL;
123}
124
125
126MSHR::Iterator
127MSHRQueue::addToReadyList(MSHR *mshr)
128{
129    if (readyList.empty() || readyList.back()->readyTime <= mshr->readyTime) {
130        return readyList.insert(readyList.end(), mshr);
131    }
132
133    MSHR::Iterator i = readyList.begin();
134    MSHR::Iterator end = readyList.end();
135    for (; i != end; ++i) {
136        if ((*i)->readyTime > mshr->readyTime) {
137            return readyList.insert(i, mshr);
138        }
139    }
140    assert(false);
141    return end;  // keep stupid compilers happy
142}
143
144
145MSHR *
146MSHRQueue::allocate(Addr addr, int size, PacketPtr &pkt,
147                    Tick when, Counter order)
148{
149    assert(!freeList.empty());
150    MSHR *mshr = freeList.front();
151    assert(mshr->getNumTargets() == 0);
152    freeList.pop_front();
153
154    mshr->allocate(addr, size, pkt, when, order);
155    mshr->allocIter = allocatedList.insert(allocatedList.end(), mshr);
156    mshr->readyIter = addToReadyList(mshr);
157
158    allocated += 1;
159    return mshr;
160}
161
162
163void
164MSHRQueue::deallocate(MSHR *mshr)
165{
166    deallocateOne(mshr);
167}
168
169MSHR::Iterator
170MSHRQueue::deallocateOne(MSHR *mshr)
171{
172    MSHR::Iterator retval = allocatedList.erase(mshr->allocIter);
173    freeList.push_front(mshr);
174    allocated--;
175    if (mshr->inService) {
176        inServiceEntries--;
177    } else {
178        readyList.erase(mshr->readyIter);
179    }
180    mshr->deallocate();
181    return retval;
182}
183
184void
185MSHRQueue::moveToFront(MSHR *mshr)
186{
187    if (!mshr->inService) {
188        assert(mshr == *(mshr->readyIter));
189        readyList.erase(mshr->readyIter);
190        mshr->readyIter = readyList.insert(readyList.begin(), mshr);
191    }
192}
193
194void
195MSHRQueue::markInService(MSHR *mshr)
196{
197    if (mshr->markInService()) {
198        deallocate(mshr);
199    } else {
200        readyList.erase(mshr->readyIter);
201        inServiceEntries += 1;
202    }
203}
204
205void
206MSHRQueue::markPending(MSHR *mshr)
207{
208    assert(mshr->inService);
209    mshr->inService = false;
210    --inServiceEntries;
211    /**
212     * @ todo might want to add rerequests to front of pending list for
213     * performance.
214     */
215    mshr->readyIter = addToReadyList(mshr);
216}
217
218void
219MSHRQueue::squash(int threadNum)
220{
221    MSHR::Iterator i = allocatedList.begin();
222    MSHR::Iterator end = allocatedList.end();
223    for (; i != end;) {
224        MSHR *mshr = *i;
225        if (mshr->threadNum == threadNum) {
226            while (mshr->hasTargets()) {
227                mshr->popTarget();
228                assert(0/*target->req->getThreadNum()*/ == threadNum);
229            }
230            assert(!mshr->hasTargets());
231            assert(mshr->ntargets==0);
232            if (!mshr->inService) {
233                i = deallocateOne(mshr);
234            } else {
235                //mshr->pkt->flags &= ~CACHE_LINE_FILL;
236                ++i;
237            }
238        } else {
239            ++i;
240        }
241    }
242}
243