1/*
2 * Copyright (c) 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: Ron Dreslinski
29 * Steve Reinhardt
30 */
31
32/**
33 * @file
34 * Stride Prefetcher template instantiations.
35 */
36
37#include "base/trace.hh"
38#include "debug/HWPrefetch.hh"
39#include "mem/cache/prefetch/stride.hh"
40
41void
42StridePrefetcher::calculatePrefetch(PacketPtr &pkt, std::list<Addr> &addresses,
| 1/*
2 * Copyright (c) 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: Ron Dreslinski
29 * Steve Reinhardt
30 */
31
32/**
33 * @file
34 * Stride Prefetcher template instantiations.
35 */
36
37#include "base/trace.hh"
38#include "debug/HWPrefetch.hh"
39#include "mem/cache/prefetch/stride.hh"
40
41void
42StridePrefetcher::calculatePrefetch(PacketPtr &pkt, std::list<Addr> &addresses,
|
44{
45 if (!pkt->req->hasPC()) {
46 DPRINTF(HWPrefetch, "ignoring request with no PC");
47 return;
48 }
49
50 Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize-1);
51 MasterID master_id = useMasterId ? pkt->req->masterId() : 0;
52 Addr pc = pkt->req->getPC();
53 assert(master_id < Max_Contexts);
54 std::list<StrideEntry*> &tab = table[master_id];
55
56 /* Scan Table for instAddr Match */
57 std::list<StrideEntry*>::iterator iter;
58 for (iter = tab.begin(); iter != tab.end(); iter++) {
59 if ((*iter)->instAddr == pc)
60 break;
61 }
62
63 if (iter != tab.end()) {
64 // Hit in table
65
66 int new_stride = blk_addr - (*iter)->missAddr;
67 bool stride_match = (new_stride == (*iter)->stride);
68
69 if (stride_match && new_stride != 0) {
70 if ((*iter)->confidence < Max_Conf)
71 (*iter)->confidence++;
72 } else {
73 (*iter)->stride = new_stride;
74 if ((*iter)->confidence > Min_Conf)
75 (*iter)->confidence = 0;
76 }
77
78 DPRINTF(HWPrefetch, "hit: PC %x blk_addr %x stride %d (%s), conf %d\n",
79 pc, blk_addr, new_stride, stride_match ? "match" : "change",
80 (*iter)->confidence);
81
82 (*iter)->missAddr = blk_addr;
83
84 if ((*iter)->confidence <= 0)
85 return;
86
87 for (int d = 1; d <= degree; d++) {
88 Addr new_addr = blk_addr + d * new_stride;
89 if (pageStop && !samePage(blk_addr, new_addr)) {
90 // Spanned the page, so now stop
91 pfSpanPage += degree - d + 1;
92 return;
93 } else {
94 DPRINTF(HWPrefetch, " queuing prefetch to %x @ %d\n",
95 new_addr, latency);
96 addresses.push_back(new_addr);
97 delays.push_back(latency);
98 }
99 }
100 } else {
101 // Miss in table
102 // Find lowest confidence and replace
103
104 DPRINTF(HWPrefetch, "miss: PC %x blk_addr %x\n", pc, blk_addr);
105
106 if (tab.size() >= 256) { //set default table size is 256
107 std::list<StrideEntry*>::iterator min_pos = tab.begin();
108 int min_conf = (*min_pos)->confidence;
109 for (iter = min_pos, ++iter; iter != tab.end(); ++iter) {
110 if ((*iter)->confidence < min_conf){
111 min_pos = iter;
112 min_conf = (*iter)->confidence;
113 }
114 }
115 DPRINTF(HWPrefetch, " replacing PC %x\n", (*min_pos)->instAddr);
116
117 // free entry and delete it
118 delete *min_pos;
119 tab.erase(min_pos);
120 }
121
122 StrideEntry *new_entry = new StrideEntry;
123 new_entry->instAddr = pc;
124 new_entry->missAddr = blk_addr;
125 new_entry->stride = 0;
126 new_entry->confidence = 0;
127 tab.push_back(new_entry);
128 }
129}
130
131
132StridePrefetcher*
133StridePrefetcherParams::create()
134{
135 return new StridePrefetcher(this);
136}
| 44{
45 if (!pkt->req->hasPC()) {
46 DPRINTF(HWPrefetch, "ignoring request with no PC");
47 return;
48 }
49
50 Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize-1);
51 MasterID master_id = useMasterId ? pkt->req->masterId() : 0;
52 Addr pc = pkt->req->getPC();
53 assert(master_id < Max_Contexts);
54 std::list<StrideEntry*> &tab = table[master_id];
55
56 /* Scan Table for instAddr Match */
57 std::list<StrideEntry*>::iterator iter;
58 for (iter = tab.begin(); iter != tab.end(); iter++) {
59 if ((*iter)->instAddr == pc)
60 break;
61 }
62
63 if (iter != tab.end()) {
64 // Hit in table
65
66 int new_stride = blk_addr - (*iter)->missAddr;
67 bool stride_match = (new_stride == (*iter)->stride);
68
69 if (stride_match && new_stride != 0) {
70 if ((*iter)->confidence < Max_Conf)
71 (*iter)->confidence++;
72 } else {
73 (*iter)->stride = new_stride;
74 if ((*iter)->confidence > Min_Conf)
75 (*iter)->confidence = 0;
76 }
77
78 DPRINTF(HWPrefetch, "hit: PC %x blk_addr %x stride %d (%s), conf %d\n",
79 pc, blk_addr, new_stride, stride_match ? "match" : "change",
80 (*iter)->confidence);
81
82 (*iter)->missAddr = blk_addr;
83
84 if ((*iter)->confidence <= 0)
85 return;
86
87 for (int d = 1; d <= degree; d++) {
88 Addr new_addr = blk_addr + d * new_stride;
89 if (pageStop && !samePage(blk_addr, new_addr)) {
90 // Spanned the page, so now stop
91 pfSpanPage += degree - d + 1;
92 return;
93 } else {
94 DPRINTF(HWPrefetch, " queuing prefetch to %x @ %d\n",
95 new_addr, latency);
96 addresses.push_back(new_addr);
97 delays.push_back(latency);
98 }
99 }
100 } else {
101 // Miss in table
102 // Find lowest confidence and replace
103
104 DPRINTF(HWPrefetch, "miss: PC %x blk_addr %x\n", pc, blk_addr);
105
106 if (tab.size() >= 256) { //set default table size is 256
107 std::list<StrideEntry*>::iterator min_pos = tab.begin();
108 int min_conf = (*min_pos)->confidence;
109 for (iter = min_pos, ++iter; iter != tab.end(); ++iter) {
110 if ((*iter)->confidence < min_conf){
111 min_pos = iter;
112 min_conf = (*iter)->confidence;
113 }
114 }
115 DPRINTF(HWPrefetch, " replacing PC %x\n", (*min_pos)->instAddr);
116
117 // free entry and delete it
118 delete *min_pos;
119 tab.erase(min_pos);
120 }
121
122 StrideEntry *new_entry = new StrideEntry;
123 new_entry->instAddr = pc;
124 new_entry->missAddr = blk_addr;
125 new_entry->stride = 0;
126 new_entry->confidence = 0;
127 tab.push_back(new_entry);
128 }
129}
130
131
132StridePrefetcher*
133StridePrefetcherParams::create()
134{
135 return new StridePrefetcher(this);
136}
|