queued.cc (14013:aeb3ca1762bb) queued.cc (14015:e709cec78417)
1/*
2 * Copyright (c) 2014-2015 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

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91}
92
93QueuedPrefetcher::QueuedPrefetcher(const QueuedPrefetcherParams *p)
94 : BasePrefetcher(p), queueSize(p->queue_size),
95 missingTranslationQueueSize(
96 p->max_prefetch_requests_with_pending_translation),
97 latency(p->latency), queueSquash(p->queue_squash),
98 queueFilter(p->queue_filter), cacheSnoop(p->cache_snoop),
1/*
2 * Copyright (c) 2014-2015 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

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91}
92
93QueuedPrefetcher::QueuedPrefetcher(const QueuedPrefetcherParams *p)
94 : BasePrefetcher(p), queueSize(p->queue_size),
95 missingTranslationQueueSize(
96 p->max_prefetch_requests_with_pending_translation),
97 latency(p->latency), queueSquash(p->queue_squash),
98 queueFilter(p->queue_filter), cacheSnoop(p->cache_snoop),
99 tagPrefetch(p->tag_prefetch)
99 tagPrefetch(p->tag_prefetch),
100 throttleControlPct(p->throttle_control_percentage)
100{
101}
102
103QueuedPrefetcher::~QueuedPrefetcher()
104{
105 // Delete the queued prefetch packets
106 for (DeferredPacket &p : pfq) {
107 delete p.pkt;
108 }
109}
110
101{
102}
103
104QueuedPrefetcher::~QueuedPrefetcher()
105{
106 // Delete the queued prefetch packets
107 for (DeferredPacket &p : pfq) {
108 delete p.pkt;
109 }
110}
111
112size_t
113QueuedPrefetcher::getMaxPermittedPrefetches(size_t total) const
114{
115 /**
116 * Throttle generated prefetches based in the accuracy of the prefetcher.
117 * Accuracy is computed based in the ratio of useful prefetches with
118 * respect to the number of issued prefetches.
119 *
120 * The throttleControlPct controls how many of the candidate addresses
121 * generated by the prefetcher will be finally turned into prefetch
122 * requests
123 * - If set to 100, all candidates can be discarded (one request
124 * will always be allowed to be generated)
125 * - Setting it to 0 will disable the throttle control, so requests are
126 * created for all candidates
127 * - If set to 60, 40% of candidates will generate a request, and the
128 * remaining 60% will be generated depending on the current accuracy
129 */
130
131 size_t max_pfs = total;
132 if (total > 0 && issuedPrefetches > 0) {
133 size_t throttle_pfs = (total * throttleControlPct) / 100;
134 size_t min_pfs = (total - throttle_pfs) == 0 ?
135 1 : (total - throttle_pfs);
136 max_pfs = min_pfs + (total - min_pfs) *
137 usefulPrefetches / issuedPrefetches;
138 }
139 return max_pfs;
140}
141
111void
112QueuedPrefetcher::notify(const PacketPtr &pkt, const PrefetchInfo &pfi)
113{
114 Addr blk_addr = blockAddress(pfi.getAddr());
115 bool is_secure = pfi.isSecure();
116
117 // Squash queued prefetches if demand miss to same line
118 if (queueSquash) {

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127 }
128 }
129 }
130
131 // Calculate prefetches given this access
132 std::vector<AddrPriority> addresses;
133 calculatePrefetch(pfi, addresses);
134
142void
143QueuedPrefetcher::notify(const PacketPtr &pkt, const PrefetchInfo &pfi)
144{
145 Addr blk_addr = blockAddress(pfi.getAddr());
146 bool is_secure = pfi.isSecure();
147
148 // Squash queued prefetches if demand miss to same line
149 if (queueSquash) {

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158 }
159 }
160 }
161
162 // Calculate prefetches given this access
163 std::vector<AddrPriority> addresses;
164 calculatePrefetch(pfi, addresses);
165
166 // Get the maximu number of prefetches that we are allowed to generate
167 size_t max_pfs = getMaxPermittedPrefetches(addresses.size());
168
135 // Queue up generated prefetches
169 // Queue up generated prefetches
170 size_t num_pfs = 0;
136 for (AddrPriority& addr_prio : addresses) {
137
138 // Block align prefetch address
139 addr_prio.first = blockAddress(addr_prio.first);
140
141 if (!samePage(addr_prio.first, pfi.getAddr())) {
142 pfSpanPage += 1;
143 }
144
145 bool can_cross_page = (tlb != nullptr);
146 if (can_cross_page || samePage(addr_prio.first, pfi.getAddr())) {
147 PrefetchInfo new_pfi(pfi,addr_prio.first);
148 pfIdentified++;
149 DPRINTF(HWPrefetch, "Found a pf candidate addr: %#x, "
150 "inserting into prefetch queue.\n", new_pfi.getAddr());
151 // Create and insert the request
152 insert(pkt, new_pfi, addr_prio.second);
171 for (AddrPriority& addr_prio : addresses) {
172
173 // Block align prefetch address
174 addr_prio.first = blockAddress(addr_prio.first);
175
176 if (!samePage(addr_prio.first, pfi.getAddr())) {
177 pfSpanPage += 1;
178 }
179
180 bool can_cross_page = (tlb != nullptr);
181 if (can_cross_page || samePage(addr_prio.first, pfi.getAddr())) {
182 PrefetchInfo new_pfi(pfi,addr_prio.first);
183 pfIdentified++;
184 DPRINTF(HWPrefetch, "Found a pf candidate addr: %#x, "
185 "inserting into prefetch queue.\n", new_pfi.getAddr());
186 // Create and insert the request
187 insert(pkt, new_pfi, addr_prio.second);
188 num_pfs += 1;
189 if (num_pfs == max_pfs) {
190 break;
191 }
153 } else {
154 DPRINTF(HWPrefetch, "Ignoring page crossing prefetch.\n");
155 }
156 }
157}
158
159PacketPtr
160QueuedPrefetcher::getPacket()

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193 DPRINTF(HWPrefetch, "Ignoring page crossing prefetch.\n");
194 }
195 }
196}
197
198PacketPtr
199QueuedPrefetcher::getPacket()

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