queued.cc (10922:5ee72f4b2931) queued.cc (10942:224c85495f96)
1/*
2 * Copyright (c) 2014 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Mitch Hayenga
38 */
39
40#include "debug/HWPrefetch.hh"
41#include "mem/cache/prefetch/queued.hh"
42#include "mem/cache/base.hh"
43
44QueuedPrefetcher::QueuedPrefetcher(const QueuedPrefetcherParams *p)
45 : BasePrefetcher(p), queueSize(p->queue_size), latency(p->latency),
46 queueSquash(p->queue_squash), queueFilter(p->queue_filter),
47 cacheSnoop(p->cache_snoop), tagPrefetch(p->tag_prefetch)
48{
49
50}
51
52QueuedPrefetcher::~QueuedPrefetcher()
53{
54 // Delete the queued prefetch packets
55 for (DeferredPacket &p : pfq) {
56 delete p.pkt->req;
57 delete p.pkt;
58 }
59}
60
61Tick
62QueuedPrefetcher::notify(const PacketPtr &pkt)
63{
64 // Verify this access type is observed by prefetcher
65 if (observeAccess(pkt)) {
66 Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize - 1);
67 bool is_secure = pkt->isSecure();
68
69 // Squash queued prefetches if demand miss to same line
70 if (queueSquash) {
71 auto itr = pfq.begin();
72 while (itr != pfq.end()) {
73 if (itr->pkt->getAddr() == blk_addr &&
74 itr->pkt->isSecure() == is_secure) {
75 delete itr->pkt->req;
76 delete itr->pkt;
77 itr = pfq.erase(itr);
78 } else {
79 ++itr;
80 }
81 }
1/*
2 * Copyright (c) 2014 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Mitch Hayenga
38 */
39
40#include "debug/HWPrefetch.hh"
41#include "mem/cache/prefetch/queued.hh"
42#include "mem/cache/base.hh"
43
44QueuedPrefetcher::QueuedPrefetcher(const QueuedPrefetcherParams *p)
45 : BasePrefetcher(p), queueSize(p->queue_size), latency(p->latency),
46 queueSquash(p->queue_squash), queueFilter(p->queue_filter),
47 cacheSnoop(p->cache_snoop), tagPrefetch(p->tag_prefetch)
48{
49
50}
51
52QueuedPrefetcher::~QueuedPrefetcher()
53{
54 // Delete the queued prefetch packets
55 for (DeferredPacket &p : pfq) {
56 delete p.pkt->req;
57 delete p.pkt;
58 }
59}
60
61Tick
62QueuedPrefetcher::notify(const PacketPtr &pkt)
63{
64 // Verify this access type is observed by prefetcher
65 if (observeAccess(pkt)) {
66 Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize - 1);
67 bool is_secure = pkt->isSecure();
68
69 // Squash queued prefetches if demand miss to same line
70 if (queueSquash) {
71 auto itr = pfq.begin();
72 while (itr != pfq.end()) {
73 if (itr->pkt->getAddr() == blk_addr &&
74 itr->pkt->isSecure() == is_secure) {
75 delete itr->pkt->req;
76 delete itr->pkt;
77 itr = pfq.erase(itr);
78 } else {
79 ++itr;
80 }
81 }
82
83 if (pfq.empty())
84 cache->deassertMemSideBusRequest(BaseCache::Request_PF);
85 }
86
87 // Calculate prefetches given this access
88 std::vector<Addr> addresses;
89 calculatePrefetch(pkt, addresses);
90
91 // Queue up generated prefetches
92 for (Addr pf_addr : addresses) {
93
94 // Block align prefetch address
95 pf_addr = pf_addr & ~(Addr)(blkSize - 1);
96
97 pfIdentified++;
98 DPRINTF(HWPrefetch, "Found a pf candidate addr: %#x, "
99 "inserting into prefetch queue.\n", pf_addr);
100
101 if (queueFilter && inPrefetch(pf_addr, is_secure)) {
102 pfBufferHit++;
103 DPRINTF(HWPrefetch, "Prefetch addr already in "
104 "prefetch queue\n");
105 continue;
106 }
107
108 if (cacheSnoop && (inCache(pf_addr, is_secure) ||
109 inMissQueue(pf_addr, is_secure))) {
110 pfInCache++;
111 DPRINTF(HWPrefetch, "Dropping redundant in "
112 "cache/MSHR prefetch addr:%#x\n", pf_addr);
113 continue;
114 }
115
116 // Create a prefetch memory request
117 Request *pf_req =
118 new Request(pf_addr, blkSize, 0, masterId);
119
120 if (is_secure) {
121 pf_req->setFlags(Request::SECURE);
122 }
123 pf_req->taskId(ContextSwitchTaskId::Prefetcher);
124 PacketPtr pf_pkt = new Packet(pf_req, MemCmd::HardPFReq);
125 pf_pkt->allocate();
126
127 if (pkt->req->hasContextId()) {
128 pf_req->setThreadContext(pkt->req->contextId(),
129 pkt->req->threadId());
130 }
131
132 if (tagPrefetch && pkt->req->hasPC()) {
133 // Tag prefetch packet with accessing pc
134 pf_pkt->req->setPC(pkt->req->getPC());
135 }
136
137 // Verify prefetch buffer space for request
138 if (pfq.size() == queueSize) {
139 pfRemovedFull++;
140 PacketPtr old_pkt = pfq.begin()->pkt;
141 DPRINTF(HWPrefetch, "Prefetch queue full, removing "
142 "oldest packet addr: %#x", old_pkt->getAddr());
143 delete old_pkt->req;
144 delete old_pkt;
145 pfq.pop_front();
146 }
147
148 Tick pf_time = curTick() + clockPeriod() * latency;
149 DPRINTF(HWPrefetch, "Prefetch queued. "
150 "addr:%#x tick:%lld.\n", pf_addr, pf_time);
151
152 pfq.emplace_back(pf_time, pf_pkt);
153 }
154 }
155
156 return pfq.empty() ? MaxTick : pfq.front().tick;
157}
158
159PacketPtr
160QueuedPrefetcher::getPacket()
161{
162 DPRINTF(HWPrefetch, "Requesting a prefetch to issue.\n");
163
164 if (pfq.empty()) {
165 DPRINTF(HWPrefetch, "No hardware prefetches available.\n");
166 return NULL;
167 }
168
169 PacketPtr pkt = pfq.begin()->pkt;
170 pfq.pop_front();
171
172 pfIssued++;
173 assert(pkt != NULL);
174 DPRINTF(HWPrefetch, "Generating prefetch for %#x.\n", pkt->getAddr());
175 return pkt;
176}
177
178bool
179QueuedPrefetcher::inPrefetch(Addr address, bool is_secure) const
180{
181 for (const DeferredPacket &dp : pfq) {
182 if (dp.pkt->getAddr() == address &&
183 dp.pkt->isSecure() == is_secure) return true;
184 }
185
186 return false;
187}
188
189void
190QueuedPrefetcher::regStats()
191{
192 BasePrefetcher::regStats();
193
194 pfIdentified
195 .name(name() + ".pfIdentified")
196 .desc("number of prefetch candidates identified");
197
198 pfBufferHit
199 .name(name() + ".pfBufferHit")
200 .desc("number of redundant prefetches already in prefetch queue");
201
202 pfInCache
203 .name(name() + ".pfInCache")
204 .desc("number of redundant prefetches already in cache/mshr dropped");
205
206 pfRemovedFull
207 .name(name() + ".pfRemovedFull")
208 .desc("number of prefetches dropped due to prefetch queue size");
209
210 pfSpanPage
211 .name(name() + ".pfSpanPage")
212 .desc("number of prefetches not generated due to page crossing");
213}
82 }
83
84 // Calculate prefetches given this access
85 std::vector<Addr> addresses;
86 calculatePrefetch(pkt, addresses);
87
88 // Queue up generated prefetches
89 for (Addr pf_addr : addresses) {
90
91 // Block align prefetch address
92 pf_addr = pf_addr & ~(Addr)(blkSize - 1);
93
94 pfIdentified++;
95 DPRINTF(HWPrefetch, "Found a pf candidate addr: %#x, "
96 "inserting into prefetch queue.\n", pf_addr);
97
98 if (queueFilter && inPrefetch(pf_addr, is_secure)) {
99 pfBufferHit++;
100 DPRINTF(HWPrefetch, "Prefetch addr already in "
101 "prefetch queue\n");
102 continue;
103 }
104
105 if (cacheSnoop && (inCache(pf_addr, is_secure) ||
106 inMissQueue(pf_addr, is_secure))) {
107 pfInCache++;
108 DPRINTF(HWPrefetch, "Dropping redundant in "
109 "cache/MSHR prefetch addr:%#x\n", pf_addr);
110 continue;
111 }
112
113 // Create a prefetch memory request
114 Request *pf_req =
115 new Request(pf_addr, blkSize, 0, masterId);
116
117 if (is_secure) {
118 pf_req->setFlags(Request::SECURE);
119 }
120 pf_req->taskId(ContextSwitchTaskId::Prefetcher);
121 PacketPtr pf_pkt = new Packet(pf_req, MemCmd::HardPFReq);
122 pf_pkt->allocate();
123
124 if (pkt->req->hasContextId()) {
125 pf_req->setThreadContext(pkt->req->contextId(),
126 pkt->req->threadId());
127 }
128
129 if (tagPrefetch && pkt->req->hasPC()) {
130 // Tag prefetch packet with accessing pc
131 pf_pkt->req->setPC(pkt->req->getPC());
132 }
133
134 // Verify prefetch buffer space for request
135 if (pfq.size() == queueSize) {
136 pfRemovedFull++;
137 PacketPtr old_pkt = pfq.begin()->pkt;
138 DPRINTF(HWPrefetch, "Prefetch queue full, removing "
139 "oldest packet addr: %#x", old_pkt->getAddr());
140 delete old_pkt->req;
141 delete old_pkt;
142 pfq.pop_front();
143 }
144
145 Tick pf_time = curTick() + clockPeriod() * latency;
146 DPRINTF(HWPrefetch, "Prefetch queued. "
147 "addr:%#x tick:%lld.\n", pf_addr, pf_time);
148
149 pfq.emplace_back(pf_time, pf_pkt);
150 }
151 }
152
153 return pfq.empty() ? MaxTick : pfq.front().tick;
154}
155
156PacketPtr
157QueuedPrefetcher::getPacket()
158{
159 DPRINTF(HWPrefetch, "Requesting a prefetch to issue.\n");
160
161 if (pfq.empty()) {
162 DPRINTF(HWPrefetch, "No hardware prefetches available.\n");
163 return NULL;
164 }
165
166 PacketPtr pkt = pfq.begin()->pkt;
167 pfq.pop_front();
168
169 pfIssued++;
170 assert(pkt != NULL);
171 DPRINTF(HWPrefetch, "Generating prefetch for %#x.\n", pkt->getAddr());
172 return pkt;
173}
174
175bool
176QueuedPrefetcher::inPrefetch(Addr address, bool is_secure) const
177{
178 for (const DeferredPacket &dp : pfq) {
179 if (dp.pkt->getAddr() == address &&
180 dp.pkt->isSecure() == is_secure) return true;
181 }
182
183 return false;
184}
185
186void
187QueuedPrefetcher::regStats()
188{
189 BasePrefetcher::regStats();
190
191 pfIdentified
192 .name(name() + ".pfIdentified")
193 .desc("number of prefetch candidates identified");
194
195 pfBufferHit
196 .name(name() + ".pfBufferHit")
197 .desc("number of redundant prefetches already in prefetch queue");
198
199 pfInCache
200 .name(name() + ".pfInCache")
201 .desc("number of redundant prefetches already in cache/mshr dropped");
202
203 pfRemovedFull
204 .name(name() + ".pfRemovedFull")
205 .desc("number of prefetches dropped due to prefetch queue size");
206
207 pfSpanPage
208 .name(name() + ".pfSpanPage")
209 .desc("number of prefetches not generated due to page crossing");
210}