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 */
30
31#include "cpu/o3/store_set.hh"
32
33#include "base/intmath.hh"
34#include "base/logging.hh"
35#include "base/trace.hh"
36#include "debug/StoreSet.hh"
37
38StoreSet::StoreSet(uint64_t clear_period, int _SSIT_size, int _LFST_size)
39    : clearPeriod(clear_period), SSITSize(_SSIT_size), LFSTSize(_LFST_size)
40{
41    DPRINTF(StoreSet, "StoreSet: Creating store set object.\n");
42    DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n",
43            SSITSize, LFSTSize);
44
45    if (!isPowerOf2(SSITSize)) {
46        fatal("Invalid SSIT size!\n");
47    }
48
49    SSIT.resize(SSITSize);
50
51    validSSIT.resize(SSITSize);
52
53    for (int i = 0; i < SSITSize; ++i)
54        validSSIT[i] = false;
55
56    if (!isPowerOf2(LFSTSize)) {
57        fatal("Invalid LFST size!\n");
58    }
59
60    LFST.resize(LFSTSize);
61
62    validLFST.resize(LFSTSize);
63
64    for (int i = 0; i < LFSTSize; ++i) {
65        validLFST[i] = false;
66        LFST[i] = 0;
67    }
68
69    indexMask = SSITSize - 1;
70
71    offsetBits = 2;
72
73    memOpsPred = 0;
74}
75
76StoreSet::~StoreSet()
77{
78}
79
80void
81StoreSet::init(uint64_t clear_period, int _SSIT_size, int _LFST_size)
82{
83    SSITSize = _SSIT_size;
84    LFSTSize = _LFST_size;
85    clearPeriod = clear_period;
86
87    DPRINTF(StoreSet, "StoreSet: Creating store set object.\n");
88    DPRINTF(StoreSet, "StoreSet: SSIT size: %i, LFST size: %i.\n",
89            SSITSize, LFSTSize);
90
91    SSIT.resize(SSITSize);
92
93    validSSIT.resize(SSITSize);
94
95    for (int i = 0; i < SSITSize; ++i)
96        validSSIT[i] = false;
97
98    LFST.resize(LFSTSize);
99
100    validLFST.resize(LFSTSize);
101
102    for (int i = 0; i < LFSTSize; ++i) {
103        validLFST[i] = false;
104        LFST[i] = 0;
105    }
106
107    indexMask = SSITSize - 1;
108
109    offsetBits = 2;
110
111    memOpsPred = 0;
112}
113
114
115void
116StoreSet::violation(Addr store_PC, Addr load_PC)
117{
118    int load_index = calcIndex(load_PC);
119    int store_index = calcIndex(store_PC);
120
121    assert(load_index < SSITSize && store_index < SSITSize);
122
123    bool valid_load_SSID = validSSIT[load_index];
124    bool valid_store_SSID = validSSIT[store_index];
125
126    if (!valid_load_SSID && !valid_store_SSID) {
127        // Calculate a new SSID here.
128        SSID new_set = calcSSID(load_PC);
129
130        validSSIT[load_index] = true;
131
132        SSIT[load_index] = new_set;
133
134        validSSIT[store_index] = true;
135
136        SSIT[store_index] = new_set;
137
138        assert(new_set < LFSTSize);
139
140        DPRINTF(StoreSet, "StoreSet: Neither load nor store had a valid "
141                "storeset, creating a new one: %i for load %#x, store %#x\n",
142                new_set, load_PC, store_PC);
143    } else if (valid_load_SSID && !valid_store_SSID) {
144        SSID load_SSID = SSIT[load_index];
145
146        validSSIT[store_index] = true;
147
148        SSIT[store_index] = load_SSID;
149
150        assert(load_SSID < LFSTSize);
151
152        DPRINTF(StoreSet, "StoreSet: Load had a valid store set.  Adding "
153                "store to that set: %i for load %#x, store %#x\n",
154                load_SSID, load_PC, store_PC);
155    } else if (!valid_load_SSID && valid_store_SSID) {
156        SSID store_SSID = SSIT[store_index];
157
158        validSSIT[load_index] = true;
159
160        SSIT[load_index] = store_SSID;
161
162        DPRINTF(StoreSet, "StoreSet: Store had a valid store set: %i for "
163                "load %#x, store %#x\n",
164                store_SSID, load_PC, store_PC);
165    } else {
166        SSID load_SSID = SSIT[load_index];
167        SSID store_SSID = SSIT[store_index];
168
169        assert(load_SSID < LFSTSize && store_SSID < LFSTSize);
170
171        // The store set with the lower number wins
172        if (store_SSID > load_SSID) {
173            SSIT[store_index] = load_SSID;
174
175            DPRINTF(StoreSet, "StoreSet: Load had smaller store set: %i; "
176                    "for load %#x, store %#x\n",
177                    load_SSID, load_PC, store_PC);
178        } else {
179            SSIT[load_index] = store_SSID;
180
181            DPRINTF(StoreSet, "StoreSet: Store had smaller store set: %i; "
182                    "for load %#x, store %#x\n",
183                    store_SSID, load_PC, store_PC);
184        }
185    }
186}
187
188void
189StoreSet::checkClear()
190{
191    memOpsPred++;
192    if (memOpsPred > clearPeriod) {
193        DPRINTF(StoreSet, "Wiping predictor state beacuse %d ld/st executed\n",
194                clearPeriod);
195        memOpsPred = 0;
196        clear();
197    }
198}
199
200void
201StoreSet::insertLoad(Addr load_PC, InstSeqNum load_seq_num)
202{
203    checkClear();
204    // Does nothing.
205    return;
206}
207
208void
209StoreSet::insertStore(Addr store_PC, InstSeqNum store_seq_num, ThreadID tid)
210{
211    int index = calcIndex(store_PC);
212
213    int store_SSID;
214
215    checkClear();
216    assert(index < SSITSize);
217
218    if (!validSSIT[index]) {
219        // Do nothing if there's no valid entry.
220        return;
221    } else {
222        store_SSID = SSIT[index];
223
224        assert(store_SSID < LFSTSize);
225
226        // Update the last store that was fetched with the current one.
227        LFST[store_SSID] = store_seq_num;
228
229        validLFST[store_SSID] = 1;
230
231        storeList[store_seq_num] = store_SSID;
232
233        DPRINTF(StoreSet, "Store %#x updated the LFST, SSID: %i\n",
234                store_PC, store_SSID);
235    }
236}
237
238InstSeqNum
239StoreSet::checkInst(Addr PC)
240{
241    int index = calcIndex(PC);
242
243    int inst_SSID;
244
245    assert(index < SSITSize);
246
247    if (!validSSIT[index]) {
248        DPRINTF(StoreSet, "Inst %#x with index %i had no SSID\n",
249                PC, index);
250
251        // Return 0 if there's no valid entry.
252        return 0;
253    } else {
254        inst_SSID = SSIT[index];
255
256        assert(inst_SSID < LFSTSize);
257
258        if (!validLFST[inst_SSID]) {
259
260            DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had no "
261                    "dependency\n", PC, index, inst_SSID);
262
263            return 0;
264        } else {
265            DPRINTF(StoreSet, "Inst %#x with index %i and SSID %i had LFST "
266                    "inum of %i\n", PC, index, inst_SSID, LFST[inst_SSID]);
267
268            return LFST[inst_SSID];
269        }
270    }
271}
272
273void
274StoreSet::issued(Addr issued_PC, InstSeqNum issued_seq_num, bool is_store)
275{
276    // This only is updated upon a store being issued.
277    if (!is_store) {
278        return;
279    }
280
281    int index = calcIndex(issued_PC);
282
283    int store_SSID;
284
285    assert(index < SSITSize);
286
287    SeqNumMapIt store_list_it = storeList.find(issued_seq_num);
288
289    if (store_list_it != storeList.end()) {
290        storeList.erase(store_list_it);
291    }
292
293    // Make sure the SSIT still has a valid entry for the issued store.
294    if (!validSSIT[index]) {
295        return;
296    }
297
298    store_SSID = SSIT[index];
299
300    assert(store_SSID < LFSTSize);
301
302    // If the last fetched store in the store set refers to the store that
303    // was just issued, then invalidate the entry.
304    if (validLFST[store_SSID] && LFST[store_SSID] == issued_seq_num) {
305        DPRINTF(StoreSet, "StoreSet: store invalidated itself in LFST.\n");
306        validLFST[store_SSID] = false;
307    }
308}
309
310void
311StoreSet::squash(InstSeqNum squashed_num, ThreadID tid)
312{
313    DPRINTF(StoreSet, "StoreSet: Squashing until inum %i\n",
314            squashed_num);
315
316    int idx;
317    SeqNumMapIt store_list_it = storeList.begin();
318
319    //@todo:Fix to only delete from correct thread
320    while (!storeList.empty()) {
321        idx = (*store_list_it).second;
322
323        if ((*store_list_it).first <= squashed_num) {
324            break;
325        }
326
327        bool younger = LFST[idx] > squashed_num;
328
329        if (validLFST[idx] && younger) {
330            DPRINTF(StoreSet, "Squashed [sn:%lli]\n", LFST[idx]);
331            validLFST[idx] = false;
332
333            storeList.erase(store_list_it++);
334        } else if (!validLFST[idx] && younger) {
335            storeList.erase(store_list_it++);
336        }
337    }
338}
339
340void
341StoreSet::clear()
342{
343    for (int i = 0; i < SSITSize; ++i) {
344        validSSIT[i] = false;
345    }
346
347    for (int i = 0; i < LFSTSize; ++i) {
348        validLFST[i] = false;
349    }
350
351    storeList.clear();
352}
353
354void
355StoreSet::dump()
356{
357    cprintf("storeList.size(): %i\n", storeList.size());
358    SeqNumMapIt store_list_it = storeList.begin();
359
360    int num = 0;
361
362    while (store_list_it != storeList.end()) {
363        cprintf("%i: [sn:%lli] SSID:%i\n",
364                num, (*store_list_it).first, (*store_list_it).second);
365        num++;
366        store_list_it++;
367    }
368}
369