1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/*
* Copyright (c) 2003-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Erik Hallnor
*/
/** @file
* Declaration of a structure to manage MSHRs.
*/
#ifndef __MEM__CACHE__MISS__MSHR_QUEUE_HH__
#define __MEM__CACHE__MISS__MSHR_QUEUE_HH__
#include <vector>
#include "mem/packet.hh"
#include "mem/cache/mshr.hh"
/**
* A Class for maintaining a list of pending and allocated memory requests.
*/
class MSHRQueue
{
private:
/** Local label (for functional print requests) */
const std::string label;
/** MSHR storage. */
MSHR *registers;
/** Holds pointers to all allocated entries. */
MSHR::List allocatedList;
/** Holds pointers to entries that haven't been sent to the bus. */
MSHR::List readyList;
/** Holds non allocated entries. */
MSHR::List freeList;
// Parameters
/**
* The total number of entries in this queue. This number is set as the
* number of entries requested plus (numReserve - 1). This allows for
* the same number of effective entries while still maintaining the reserve.
*/
const int numEntries;
/**
* The number of entries to hold in reserve. This is needed because copy
* operations can allocate upto 4 entries at one time.
*/
const int numReserve;
MSHR::Iterator addToReadyList(MSHR *mshr);
public:
/** The number of allocated entries. */
int allocated;
/** The number of entries that have been forwarded to the bus. */
int inServiceEntries;
/** The index of this queue within the cache (MSHR queue vs. write
* buffer). */
const int index;
/**
* Create a queue with a given number of entries.
* @param num_entrys The number of entries in this queue.
* @param reserve The minimum number of entries needed to satisfy
* any access.
*/
MSHRQueue(const std::string &_label, int num_entries, int reserve,
int index);
/** Destructor */
~MSHRQueue();
/**
* Find the first MSHR that matches the provided address.
* @param addr The address to find.
* @return Pointer to the matching MSHR, null if not found.
*/
MSHR *findMatch(Addr addr) const;
/**
* Find and return all the matching entries in the provided vector.
* @param addr The address to find.
* @param matches The vector to return pointers to the matching entries.
* @return True if any matches are found, false otherwise.
* @todo Typedef the vector??
*/
bool findMatches(Addr addr, std::vector<MSHR*>& matches) const;
/**
* Find any pending requests that overlap the given request.
* @param pkt The request to find.
* @return A pointer to the earliest matching MSHR.
*/
MSHR *findPending(Addr addr, int size) const;
bool checkFunctional(PacketPtr pkt, Addr blk_addr);
/**
* Allocates a new MSHR for the request and size. This places the request
* as the first target in the MSHR.
* @param pkt The request to handle.
* @param size The number in bytes to fetch from memory.
* @return The a pointer to the MSHR allocated.
*
* @pre There are free entries.
*/
MSHR *allocate(Addr addr, int size, PacketPtr &pkt,
Tick when, Counter order);
/**
* Removes the given MSHR from the queue. This places the MSHR on the
* free list.
* @param mshr
*/
void deallocate(MSHR *mshr);
/**
* Remove a MSHR from the queue. Returns an iterator into the
* allocatedList for faster squash implementation.
* @param mshr The MSHR to remove.
* @return An iterator to the next entry in the allocatedList.
*/
MSHR::Iterator deallocateOne(MSHR *mshr);
/**
* Moves the MSHR to the front of the pending list if it is not
* in service.
* @param mshr The entry to move.
*/
void moveToFront(MSHR *mshr);
/**
* Mark the given MSHR as in service. This removes the MSHR from the
* readyList. Deallocates the MSHR if it does not expect a response.
* @param mshr The MSHR to mark in service.
*/
void markInService(MSHR *mshr, PacketPtr pkt);
/**
* Mark an in service entry as pending, used to resend a request.
* @param mshr The MSHR to resend.
*/
void markPending(MSHR *mshr);
/**
* Squash outstanding requests with the given thread number. If a request
* is in service, just squashes the targets.
* @param threadNum The thread to squash.
*/
void squash(int threadNum);
/**
* Returns true if the pending list is not empty.
* @return True if there are outstanding requests.
*/
bool havePending() const
{
return !readyList.empty();
}
/**
* Returns true if there are no free entries.
* @return True if this queue is full.
*/
bool isFull() const
{
return (allocated > numEntries - numReserve);
}
/**
* Returns the MSHR at the head of the readyList.
* @return The next request to service.
*/
MSHR *getNextMSHR() const
{
if (readyList.empty() || readyList.front()->readyTime > curTick) {
return NULL;
}
return readyList.front();
}
Tick nextMSHRReadyTime() const
{
return readyList.empty() ? MaxTick : readyList.front()->readyTime;
}
};
#endif //__MEM__CACHE__MISS__MSHR_QUEUE_HH__
|
