1/**
2 * Copyright (c) 2018 Metempsy Technology Consulting
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;

--- 24 unchanged lines hidden (view full) ---

33 #include "mem/cache/base.hh"
34 #include "mem/cache/prefetch/associative_set_impl.hh"
35 #include "params/IndirectMemoryPrefetcher.hh"
36
37IndirectMemoryPrefetcher::IndirectMemoryPrefetcher(
38 const IndirectMemoryPrefetcherParams *p) : QueuedPrefetcher(p),
39 maxPrefetchDistance(p->max_prefetch_distance),
40 shiftValues(p->shift_values), prefetchThreshold(p->prefetch_threshold),
41 streamCounterThreshold(p->stream_counter_threshold),
42 streamingDistance(p->streaming_distance),
43 prefetchTable(p->pt_table_assoc, p->pt_table_entries,
44 p->pt_table_indexing_policy, p->pt_table_replacement_policy,
45 PrefetchTableEntry(p->num_indirect_counter_bits)),
46 ipd(p->ipd_table_assoc, p->ipd_table_entries, p->ipd_table_indexing_policy,
47 p->ipd_table_replacement_policy,
48 IndirectPatternDetectorEntry(p->addr_array_len, shiftValues.size())),
49 ipdEntryTrackingMisses(nullptr),
50#if THE_ISA != NULL_ISA
51 byteOrder(TheISA::GuestByteOrder)
52#else
53 byteOrder((ByteOrder) -1)

--- 76 unchanged lines hidden (view full) ---

130 // Not enabled (no pattern detected in this stream),
131 // add or update an entry in the pattern detector and
132 // start tracking misses
133 allocateOrUpdateIPDEntry(pt_entry, index);
134 } else if (read_index) {
135 // Enabled entry, update the index
136 pt_entry->index = index;
137 if (!pt_entry->increasedIndirectCounter) {
138 pt_entry->indirectCounter--;
139 } else {
140 // Set this to false, to see if the new index
141 // has any match
142 pt_entry->increasedIndirectCounter = false;
143 }
144
145 // If the counter is high enough, start prefetching
146 if (pt_entry->indirectCounter > prefetchThreshold) {
147 unsigned distance = maxPrefetchDistance *
148 pt_entry->indirectCounter.calcSaturation();
149 for (int delta = 1; delta < distance; delta += 1) {
150 Addr pf_addr = pt_entry->baseAddr +
151 (pt_entry->index << pt_entry->shift);
152 addresses.push_back(AddrPriority(pf_addr, 0));
153 }
154 }
155 }
156 }

--- 73 unchanged lines hidden (view full) ---

230 if (ba_array[idx] == (miss_addr - (entry->idx2 << shift))) {
231 // Match found!
232 // Fill the corresponding pt_entry
233 PrefetchTableEntry *pt_entry =
234 (PrefetchTableEntry *) entry->getTag();
235 pt_entry->baseAddr = ba_array[idx];
236 pt_entry->shift = shift;
237 pt_entry->enabled = true;
238 pt_entry->indirectCounter.reset();
239 // Release the current IPD Entry
240 entry->reset();
241 // Do not track more misses
242 ipdEntryTrackingMisses = nullptr;
243 return;
244 }
245 idx += 1;
246 }
247 }
248}
249
250void
251IndirectMemoryPrefetcher::checkAccessMatchOnActiveEntries(Addr addr)
252{
253 for (auto &pt_entry : prefetchTable) {
254 if (pt_entry.enabled) {
255 if (addr == pt_entry.baseAddr +
256 (pt_entry.index << pt_entry.shift)) {
257 pt_entry.indirectCounter++;
258 pt_entry.increasedIndirectCounter = true;
259 }
260 }
261 }
262}
263
264IndirectMemoryPrefetcher*
265IndirectMemoryPrefetcherParams::create()
266{
267 return new IndirectMemoryPrefetcher(this);
268}