mshr.cc revision 4666 
1/*
2 * Copyright (c) 2002-2005 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 *          Dave Greene
30 */
31
32/**
33 * @file
34 * Miss Status and Handling Register (MSHR) definitions.
35 */
36
37#include <assert.h>
38#include <string>
39#include <vector>
40#include <algorithm>
41
42#include "mem/cache/miss/mshr.hh"
43#include "sim/core.hh" // for curTick
44#include "sim/host.hh"
45#include "base/misc.hh"
46#include "mem/cache/cache.hh"
47
48using namespace std;
49
50MSHR::MSHR()
51{
52    inService = false;
53    ntargets = 0;
54    threadNum = -1;
55}
56
57void
58MSHR::allocate(Addr _addr, int _size, PacketPtr target,
59               Tick when, Counter _order)
60{
61    addr = _addr;
62    size = _size;
63    readyTick = when;
64    order = _order;
65    assert(target);
66    isCacheFill = false;
67    needsExclusive = target->needsExclusive();
68    _isUncacheable = target->req->isUncacheable();
69    inService = false;
70    threadNum = 0;
71    ntargets = 1;
72    // Don't know of a case where we would allocate a new MSHR for a
73    // snoop (mem-side request), so set cpuSide to true here.
74    targets.push_back(Target(target, when, _order, true));
75    assert(deferredTargets.empty());
76    deferredNeedsExclusive = false;
77    pendingInvalidate = false;
78}
79
80void
81MSHR::deallocate()
82{
83    assert(targets.empty());
84    assert(deferredTargets.empty());
85    assert(ntargets == 0);
86    inService = false;
87    //allocIter = NULL;
88    //readyIter = NULL;
89}
90
91/*
92 * Adds a target to an MSHR
93 */
94void
95MSHR::allocateTarget(PacketPtr target, Tick when, Counter _order)
96{
97    if (inService) {
98        if (!deferredTargets.empty() || pendingInvalidate ||
99            (!needsExclusive && target->needsExclusive())) {
100            // need to put on deferred list
101            deferredTargets.push_back(Target(target, when, _order, true));
102            if (target->needsExclusive()) {
103                deferredNeedsExclusive = true;
104            }
105        } else {
106            // still OK to append to outstanding request
107            targets.push_back(Target(target, when, _order, true));
108        }
109    } else {
110        if (target->needsExclusive()) {
111            needsExclusive = true;
112        }
113
114        targets.push_back(Target(target, when, _order, true));
115    }
116
117    ++ntargets;
118}
119
120void
121MSHR::allocateSnoopTarget(PacketPtr target, Tick when, Counter _order)
122{
123    assert(inService); // don't bother to call otherwise
124
125    if (pendingInvalidate) {
126        // a prior snoop has already appended an invalidation, so
127        // logically we don't have the block anymore...
128        return;
129    }
130
131    if (needsExclusive) {
132        // We're awaiting an exclusive copy, so ownership is pending.
133        // It's up to us to respond once the data arrives.
134        target->assertMemInhibit();
135    } else if (target->needsExclusive()) {
136        // This transaction will take away our pending copy
137        pendingInvalidate = true;
138    } else {
139        // If we're not going to supply data or perform an
140        // invalidation, we don't need to save this.
141        return;
142    }
143
144    targets.push_back(Target(target, when, _order, false));
145    ++ntargets;
146}
147
148
149bool
150MSHR::promoteDeferredTargets()
151{
152    if (deferredTargets.empty()) {
153        return false;
154    }
155
156    assert(targets.empty());
157    targets = deferredTargets;
158    deferredTargets.clear();
159    assert(targets.size() == ntargets);
160
161    needsExclusive = deferredNeedsExclusive;
162    pendingInvalidate = false;
163    deferredNeedsExclusive = false;
164    order = targets.front().order;
165    readyTick = std::max(curTick, targets.front().time);
166
167    return true;
168}
169
170
171void
172MSHR::dump()
173{
174    ccprintf(cerr,
175             "inService: %d thread: %d\n"
176             "Addr: %x ntargets %d\n"
177             "Targets:\n",
178             inService, threadNum, addr, ntargets);
179
180    TargetListIterator tar_it = targets.begin();
181    for (int i = 0; i < ntargets; i++) {
182        assert(tar_it != targets.end());
183
184        ccprintf(cerr, "\t%d: Addr: %x cmd: %s\n",
185                 i, tar_it->pkt->getAddr(), tar_it->pkt->cmdString());
186
187        tar_it++;
188    }
189    ccprintf(cerr, "\n");
190}
191
192MSHR::~MSHR()
193{
194}
195