1/*
2 * Copyright (c) 2004-2006 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: Kevin Lim
29 * Korey Sewell
30 */
31
32#ifndef __CPU_O3_ROB_HH__
33#define __CPU_O3_ROB_HH__
34
35#include <string>
36#include <utility>
37#include <vector>
38
39#include "config/the_isa.hh"
40
41/**
42 * ROB class. The ROB is largely what drives squashing.
43 */
44template <class Impl>
45class ROB
46{
47 protected:
48 typedef TheISA::RegIndex RegIndex;
49 public:
50 //Typedefs from the Impl.
51 typedef typename Impl::O3CPU O3CPU;
52 typedef typename Impl::DynInstPtr DynInstPtr;
53
54 typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo;
55 typedef typename std::list<DynInstPtr>::iterator InstIt;
56
57 /** Possible ROB statuses. */
58 enum Status {
59 Running,
60 Idle,
61 ROBSquashing
62 };
63
64 /** SMT ROB Sharing Policy */
65 enum ROBPolicy{
66 Dynamic,
67 Partitioned,
68 Threshold
69 };
70
71 private:
72 /** Per-thread ROB status. */
73 Status robStatus[Impl::MaxThreads];
74
75 /** ROB resource sharing policy for SMT mode. */
76 ROBPolicy robPolicy;
77
78 public:
79 /** ROB constructor.
80 * @param _numEntries Number of entries in ROB.
81 * @param _squashWidth Number of instructions that can be squashed in a
82 * single cycle.
83 * @param _smtROBPolicy ROB Partitioning Scheme for SMT.
84 * @param _smtROBThreshold Max Resources(by %) a thread can have in the ROB.
85 * @param _numThreads The number of active threads.
86 */
87 ROB(O3CPU *_cpu, unsigned _numEntries, unsigned _squashWidth,
88 std::string smtROBPolicy, unsigned _smtROBThreshold,
89 ThreadID _numThreads);
90
91 std::string name() const;
92
93 /** Sets pointer to the list of active threads.
94 * @param at_ptr Pointer to the list of active threads.
95 */
96 void setActiveThreads(std::list<ThreadID> *at_ptr);
97
98 /** Switches out the ROB. */
99 void switchOut();
100
101 /** Takes over another CPU's thread. */
102 void takeOverFrom();
103
104 /** Function to insert an instruction into the ROB. Note that whatever
105 * calls this function must ensure that there is enough space within the
106 * ROB for the new instruction.
107 * @param inst The instruction being inserted into the ROB.
108 */
109 void insertInst(DynInstPtr &inst);
110
111 /** Returns pointer to the head instruction within the ROB. There is
112 * no guarantee as to the return value if the ROB is empty.
113 * @retval Pointer to the DynInst that is at the head of the ROB.
114 */
115// DynInstPtr readHeadInst();
116
117 /** Returns a pointer to the head instruction of a specific thread within
118 * the ROB.
119 * @return Pointer to the DynInst that is at the head of the ROB.
120 */
121 DynInstPtr readHeadInst(ThreadID tid);
122
123 /** Returns pointer to the tail instruction within the ROB. There is
124 * no guarantee as to the return value if the ROB is empty.
125 * @retval Pointer to the DynInst that is at the tail of the ROB.
126 */
127// DynInstPtr readTailInst();
128
129 /** Returns a pointer to the tail instruction of a specific thread within
130 * the ROB.
131 * @return Pointer to the DynInst that is at the tail of the ROB.
132 */
133 DynInstPtr readTailInst(ThreadID tid);
134
135 /** Retires the head instruction, removing it from the ROB. */
136// void retireHead();
137
138 /** Retires the head instruction of a specific thread, removing it from the
139 * ROB.
140 */
141 void retireHead(ThreadID tid);
142
143 /** Is the oldest instruction across all threads ready. */
144// bool isHeadReady();
145
146 /** Is the oldest instruction across a particular thread ready. */
147 bool isHeadReady(ThreadID tid);
148
149 /** Is there any commitable head instruction across all threads ready. */
150 bool canCommit();
151
152 /** Re-adjust ROB partitioning. */
153 void resetEntries();
154
155 /** Number of entries needed For 'num_threads' amount of threads. */
156 int entryAmount(ThreadID num_threads);
157
158 /** Returns the number of total free entries in the ROB. */
159 unsigned numFreeEntries();
160
161 /** Returns the number of free entries in a specific ROB paritition. */
162 unsigned numFreeEntries(ThreadID tid);
163
164 /** Returns the maximum number of entries for a specific thread. */
165 unsigned getMaxEntries(ThreadID tid)
166 { return maxEntries[tid]; }
167
168 /** Returns the number of entries being used by a specific thread. */
169 unsigned getThreadEntries(ThreadID tid)
170 { return threadEntries[tid]; }
171
172 /** Returns if the ROB is full. */
173 bool isFull()
174 { return numInstsInROB == numEntries; }
175
176 /** Returns if a specific thread's partition is full. */
177 bool isFull(ThreadID tid)
178 { return threadEntries[tid] == numEntries; }
179
180 /** Returns if the ROB is empty. */
181 bool isEmpty()
182 { return numInstsInROB == 0; }
183
184 /** Returns if a specific thread's partition is empty. */
185 bool isEmpty(ThreadID tid)
186 { return threadEntries[tid] == 0; }
187
188 /** Executes the squash, marking squashed instructions. */
189 void doSquash(ThreadID tid);
190
191 /** Squashes all instructions younger than the given sequence number for
192 * the specific thread.
193 */
194 void squash(InstSeqNum squash_num, ThreadID tid);
195
196 /** Updates the head instruction with the new oldest instruction. */
197 void updateHead();
198
199 /** Updates the tail instruction with the new youngest instruction. */
200 void updateTail();
201
202 /** Reads the PC of the oldest head instruction. */
203// uint64_t readHeadPC();
204
205 /** Reads the PC of the head instruction of a specific thread. */
206// uint64_t readHeadPC(ThreadID tid);
207
208 /** Reads the next PC of the oldest head instruction. */
209// uint64_t readHeadNextPC();
210
211 /** Reads the next PC of the head instruction of a specific thread. */
212// uint64_t readHeadNextPC(ThreadID tid);
213
214 /** Reads the sequence number of the oldest head instruction. */
215// InstSeqNum readHeadSeqNum();
216
217 /** Reads the sequence number of the head instruction of a specific thread.
218 */
219// InstSeqNum readHeadSeqNum(ThreadID tid);
220
221 /** Reads the PC of the youngest tail instruction. */
222// uint64_t readTailPC();
223
224 /** Reads the PC of the tail instruction of a specific thread. */
225// uint64_t readTailPC(ThreadID tid);
226
227 /** Reads the sequence number of the youngest tail instruction. */
228// InstSeqNum readTailSeqNum();
229
230 /** Reads the sequence number of tail instruction of a specific thread. */
231// InstSeqNum readTailSeqNum(ThreadID tid);
232
233 /** Checks if the ROB is still in the process of squashing instructions.
234 * @retval Whether or not the ROB is done squashing.
235 */
236 bool isDoneSquashing(ThreadID tid) const
237 { return doneSquashing[tid]; }
238
239 /** Checks if the ROB is still in the process of squashing instructions for
240 * any thread.
241 */
242 bool isDoneSquashing();
243
244 /** This is more of a debugging function than anything. Use
245 * numInstsInROB to get the instructions in the ROB unless you are
246 * double checking that variable.
247 */
248 int countInsts();
249
250 /** This is more of a debugging function than anything. Use
251 * threadEntries to get the instructions in the ROB unless you are
252 * double checking that variable.
253 */
254 int countInsts(ThreadID tid);
255
256 /** Registers statistics. */
257 void regStats();
258
259 private:
260 /** Pointer to the CPU. */
261 O3CPU *cpu;
262
263 /** Active Threads in CPU */
264 std::list<ThreadID> *activeThreads;
265
266 /** Number of instructions in the ROB. */
267 unsigned numEntries;
268
269 /** Entries Per Thread */
270 unsigned threadEntries[Impl::MaxThreads];
271
272 /** Max Insts a Thread Can Have in the ROB */
273 unsigned maxEntries[Impl::MaxThreads];
274
275 /** ROB List of Instructions */
276 std::list<DynInstPtr> instList[Impl::MaxThreads];
277
278 /** Number of instructions that can be squashed in a single cycle. */
279 unsigned squashWidth;
280
281 public:
282 /** Iterator pointing to the instruction which is the last instruction
283 * in the ROB. This may at times be invalid (ie when the ROB is empty),
284 * however it should never be incorrect.
285 */
286 InstIt tail;
287
288 /** Iterator pointing to the instruction which is the first instruction in
289 * in the ROB*/
290 InstIt head;
291
292 private:
293 /** Iterator used for walking through the list of instructions when
294 * squashing. Used so that there is persistent state between cycles;
295 * when squashing, the instructions are marked as squashed but not
296 * immediately removed, meaning the tail iterator remains the same before
297 * and after a squash.
298 * This will always be set to cpu->instList.end() if it is invalid.
299 */
300 InstIt squashIt[Impl::MaxThreads];
301
302 public:
303 /** Number of instructions in the ROB. */
304 int numInstsInROB;
305
306 /** Dummy instruction returned if there are no insts left. */
307 DynInstPtr dummyInst;
308
309 private:
310 /** The sequence number of the squashed instruction. */
311 InstSeqNum squashedSeqNum[Impl::MaxThreads];
312
313 /** Is the ROB done squashing. */
314 bool doneSquashing[Impl::MaxThreads];
315
316 /** Number of active threads. */
317 ThreadID numThreads;
318
319 // The number of rob_reads
320 Stats::Scalar robReads;
321 // The number of rob_writes
322 Stats::Scalar robWrites;
323};
324
325#endif //__CPU_O3_ROB_HH__
2 * Copyright (c) 2004-2006 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: Kevin Lim
29 * Korey Sewell
30 */
31
32#ifndef __CPU_O3_ROB_HH__
33#define __CPU_O3_ROB_HH__
34
35#include <string>
36#include <utility>
37#include <vector>
38
39#include "config/the_isa.hh"
40
41/**
42 * ROB class. The ROB is largely what drives squashing.
43 */
44template <class Impl>
45class ROB
46{
47 protected:
48 typedef TheISA::RegIndex RegIndex;
49 public:
50 //Typedefs from the Impl.
51 typedef typename Impl::O3CPU O3CPU;
52 typedef typename Impl::DynInstPtr DynInstPtr;
53
54 typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo;
55 typedef typename std::list<DynInstPtr>::iterator InstIt;
56
57 /** Possible ROB statuses. */
58 enum Status {
59 Running,
60 Idle,
61 ROBSquashing
62 };
63
64 /** SMT ROB Sharing Policy */
65 enum ROBPolicy{
66 Dynamic,
67 Partitioned,
68 Threshold
69 };
70
71 private:
72 /** Per-thread ROB status. */
73 Status robStatus[Impl::MaxThreads];
74
75 /** ROB resource sharing policy for SMT mode. */
76 ROBPolicy robPolicy;
77
78 public:
79 /** ROB constructor.
80 * @param _numEntries Number of entries in ROB.
81 * @param _squashWidth Number of instructions that can be squashed in a
82 * single cycle.
83 * @param _smtROBPolicy ROB Partitioning Scheme for SMT.
84 * @param _smtROBThreshold Max Resources(by %) a thread can have in the ROB.
85 * @param _numThreads The number of active threads.
86 */
87 ROB(O3CPU *_cpu, unsigned _numEntries, unsigned _squashWidth,
88 std::string smtROBPolicy, unsigned _smtROBThreshold,
89 ThreadID _numThreads);
90
91 std::string name() const;
92
93 /** Sets pointer to the list of active threads.
94 * @param at_ptr Pointer to the list of active threads.
95 */
96 void setActiveThreads(std::list<ThreadID> *at_ptr);
97
98 /** Switches out the ROB. */
99 void switchOut();
100
101 /** Takes over another CPU's thread. */
102 void takeOverFrom();
103
104 /** Function to insert an instruction into the ROB. Note that whatever
105 * calls this function must ensure that there is enough space within the
106 * ROB for the new instruction.
107 * @param inst The instruction being inserted into the ROB.
108 */
109 void insertInst(DynInstPtr &inst);
110
111 /** Returns pointer to the head instruction within the ROB. There is
112 * no guarantee as to the return value if the ROB is empty.
113 * @retval Pointer to the DynInst that is at the head of the ROB.
114 */
115// DynInstPtr readHeadInst();
116
117 /** Returns a pointer to the head instruction of a specific thread within
118 * the ROB.
119 * @return Pointer to the DynInst that is at the head of the ROB.
120 */
121 DynInstPtr readHeadInst(ThreadID tid);
122
123 /** Returns pointer to the tail instruction within the ROB. There is
124 * no guarantee as to the return value if the ROB is empty.
125 * @retval Pointer to the DynInst that is at the tail of the ROB.
126 */
127// DynInstPtr readTailInst();
128
129 /** Returns a pointer to the tail instruction of a specific thread within
130 * the ROB.
131 * @return Pointer to the DynInst that is at the tail of the ROB.
132 */
133 DynInstPtr readTailInst(ThreadID tid);
134
135 /** Retires the head instruction, removing it from the ROB. */
136// void retireHead();
137
138 /** Retires the head instruction of a specific thread, removing it from the
139 * ROB.
140 */
141 void retireHead(ThreadID tid);
142
143 /** Is the oldest instruction across all threads ready. */
144// bool isHeadReady();
145
146 /** Is the oldest instruction across a particular thread ready. */
147 bool isHeadReady(ThreadID tid);
148
149 /** Is there any commitable head instruction across all threads ready. */
150 bool canCommit();
151
152 /** Re-adjust ROB partitioning. */
153 void resetEntries();
154
155 /** Number of entries needed For 'num_threads' amount of threads. */
156 int entryAmount(ThreadID num_threads);
157
158 /** Returns the number of total free entries in the ROB. */
159 unsigned numFreeEntries();
160
161 /** Returns the number of free entries in a specific ROB paritition. */
162 unsigned numFreeEntries(ThreadID tid);
163
164 /** Returns the maximum number of entries for a specific thread. */
165 unsigned getMaxEntries(ThreadID tid)
166 { return maxEntries[tid]; }
167
168 /** Returns the number of entries being used by a specific thread. */
169 unsigned getThreadEntries(ThreadID tid)
170 { return threadEntries[tid]; }
171
172 /** Returns if the ROB is full. */
173 bool isFull()
174 { return numInstsInROB == numEntries; }
175
176 /** Returns if a specific thread's partition is full. */
177 bool isFull(ThreadID tid)
178 { return threadEntries[tid] == numEntries; }
179
180 /** Returns if the ROB is empty. */
181 bool isEmpty()
182 { return numInstsInROB == 0; }
183
184 /** Returns if a specific thread's partition is empty. */
185 bool isEmpty(ThreadID tid)
186 { return threadEntries[tid] == 0; }
187
188 /** Executes the squash, marking squashed instructions. */
189 void doSquash(ThreadID tid);
190
191 /** Squashes all instructions younger than the given sequence number for
192 * the specific thread.
193 */
194 void squash(InstSeqNum squash_num, ThreadID tid);
195
196 /** Updates the head instruction with the new oldest instruction. */
197 void updateHead();
198
199 /** Updates the tail instruction with the new youngest instruction. */
200 void updateTail();
201
202 /** Reads the PC of the oldest head instruction. */
203// uint64_t readHeadPC();
204
205 /** Reads the PC of the head instruction of a specific thread. */
206// uint64_t readHeadPC(ThreadID tid);
207
208 /** Reads the next PC of the oldest head instruction. */
209// uint64_t readHeadNextPC();
210
211 /** Reads the next PC of the head instruction of a specific thread. */
212// uint64_t readHeadNextPC(ThreadID tid);
213
214 /** Reads the sequence number of the oldest head instruction. */
215// InstSeqNum readHeadSeqNum();
216
217 /** Reads the sequence number of the head instruction of a specific thread.
218 */
219// InstSeqNum readHeadSeqNum(ThreadID tid);
220
221 /** Reads the PC of the youngest tail instruction. */
222// uint64_t readTailPC();
223
224 /** Reads the PC of the tail instruction of a specific thread. */
225// uint64_t readTailPC(ThreadID tid);
226
227 /** Reads the sequence number of the youngest tail instruction. */
228// InstSeqNum readTailSeqNum();
229
230 /** Reads the sequence number of tail instruction of a specific thread. */
231// InstSeqNum readTailSeqNum(ThreadID tid);
232
233 /** Checks if the ROB is still in the process of squashing instructions.
234 * @retval Whether or not the ROB is done squashing.
235 */
236 bool isDoneSquashing(ThreadID tid) const
237 { return doneSquashing[tid]; }
238
239 /** Checks if the ROB is still in the process of squashing instructions for
240 * any thread.
241 */
242 bool isDoneSquashing();
243
244 /** This is more of a debugging function than anything. Use
245 * numInstsInROB to get the instructions in the ROB unless you are
246 * double checking that variable.
247 */
248 int countInsts();
249
250 /** This is more of a debugging function than anything. Use
251 * threadEntries to get the instructions in the ROB unless you are
252 * double checking that variable.
253 */
254 int countInsts(ThreadID tid);
255
256 /** Registers statistics. */
257 void regStats();
258
259 private:
260 /** Pointer to the CPU. */
261 O3CPU *cpu;
262
263 /** Active Threads in CPU */
264 std::list<ThreadID> *activeThreads;
265
266 /** Number of instructions in the ROB. */
267 unsigned numEntries;
268
269 /** Entries Per Thread */
270 unsigned threadEntries[Impl::MaxThreads];
271
272 /** Max Insts a Thread Can Have in the ROB */
273 unsigned maxEntries[Impl::MaxThreads];
274
275 /** ROB List of Instructions */
276 std::list<DynInstPtr> instList[Impl::MaxThreads];
277
278 /** Number of instructions that can be squashed in a single cycle. */
279 unsigned squashWidth;
280
281 public:
282 /** Iterator pointing to the instruction which is the last instruction
283 * in the ROB. This may at times be invalid (ie when the ROB is empty),
284 * however it should never be incorrect.
285 */
286 InstIt tail;
287
288 /** Iterator pointing to the instruction which is the first instruction in
289 * in the ROB*/
290 InstIt head;
291
292 private:
293 /** Iterator used for walking through the list of instructions when
294 * squashing. Used so that there is persistent state between cycles;
295 * when squashing, the instructions are marked as squashed but not
296 * immediately removed, meaning the tail iterator remains the same before
297 * and after a squash.
298 * This will always be set to cpu->instList.end() if it is invalid.
299 */
300 InstIt squashIt[Impl::MaxThreads];
301
302 public:
303 /** Number of instructions in the ROB. */
304 int numInstsInROB;
305
306 /** Dummy instruction returned if there are no insts left. */
307 DynInstPtr dummyInst;
308
309 private:
310 /** The sequence number of the squashed instruction. */
311 InstSeqNum squashedSeqNum[Impl::MaxThreads];
312
313 /** Is the ROB done squashing. */
314 bool doneSquashing[Impl::MaxThreads];
315
316 /** Number of active threads. */
317 ThreadID numThreads;
318
319 // The number of rob_reads
320 Stats::Scalar robReads;
321 // The number of rob_writes
322 Stats::Scalar robWrites;
323};
324
325#endif //__CPU_O3_ROB_HH__