compressed_tags.cc (13946:8e96e9be7f2c) compressed_tags.cc (13947:4cf8087cab09)
1/*
2 * Copyright (c) 2018 Inria
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;

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58 // Initialize all blocks
59 unsigned blk_index = 0; // index into blks array
60 for (unsigned superblock_index = 0; superblock_index < numSectors;
61 superblock_index++)
62 {
63 // Locate next cache superblock
64 SuperBlk* superblock = &superBlks[superblock_index];
65
1/*
2 * Copyright (c) 2018 Inria
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;

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

58 // Initialize all blocks
59 unsigned blk_index = 0; // index into blks array
60 for (unsigned superblock_index = 0; superblock_index < numSectors;
61 superblock_index++)
62 {
63 // Locate next cache superblock
64 SuperBlk* superblock = &superBlks[superblock_index];
65
66 // Superblocks must be aware of the block size due to their co-
67 // allocation conditions
68 superblock->setBlkSize(blkSize);
69
66 // Link block to indexing policy
67 indexingPolicy->setEntry(superblock, superblock_index);
68
69 // Associate a replacement data entry to the block
70 superblock->replacementData = replacementPolicy->instantiateEntry();
71
72 // Initialize all blocks in this superblock
73 superblock->blks.resize(numBlocksPerSector, nullptr);

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91 blk->setSectorOffset(k);
92
93 // Update block index
94 ++blk_index;
95 }
96 }
97}
98
70 // Link block to indexing policy
71 indexingPolicy->setEntry(superblock, superblock_index);
72
73 // Associate a replacement data entry to the block
74 superblock->replacementData = replacementPolicy->instantiateEntry();
75
76 // Initialize all blocks in this superblock
77 superblock->blks.resize(numBlocksPerSector, nullptr);

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95 blk->setSectorOffset(k);
96
97 // Update block index
98 ++blk_index;
99 }
100 }
101}
102
99bool
100CompressedTags::canCoAllocate(const SuperBlk* superblock,
101 const std::size_t compressed_size) const
102{
103 // Simple co-allocation function: at most numBlocksPerSector blocks that
104 // compress at least to (100/numBlocksPerSector)% of their original size
105 // can share a superblock
106 return superblock->isCompressed() &&
107 (compressed_size <= (blkSize * 8) / numBlocksPerSector);
108}
109
110CacheBlk*
111CompressedTags::findVictim(Addr addr, const bool is_secure,
112 const std::size_t compressed_size,
113 std::vector<CacheBlk*>& evict_blks) const
114{
115 // Get all possible locations of this superblock
116 const std::vector<ReplaceableEntry*> superblock_entries =
117 indexingPolicy->getPossibleEntries(addr);

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122 SuperBlk* victim_superblock = nullptr;
123 bool is_co_allocation = false;
124 const uint64_t offset = extractSectorOffset(addr);
125 for (const auto& entry : superblock_entries){
126 SuperBlk* superblock = static_cast<SuperBlk*>(entry);
127 if ((tag == superblock->getTag()) && superblock->isValid() &&
128 (is_secure == superblock->isSecure()) &&
129 !superblock->blks[offset]->isValid() &&
103CacheBlk*
104CompressedTags::findVictim(Addr addr, const bool is_secure,
105 const std::size_t compressed_size,
106 std::vector<CacheBlk*>& evict_blks) const
107{
108 // Get all possible locations of this superblock
109 const std::vector<ReplaceableEntry*> superblock_entries =
110 indexingPolicy->getPossibleEntries(addr);

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115 SuperBlk* victim_superblock = nullptr;
116 bool is_co_allocation = false;
117 const uint64_t offset = extractSectorOffset(addr);
118 for (const auto& entry : superblock_entries){
119 SuperBlk* superblock = static_cast<SuperBlk*>(entry);
120 if ((tag == superblock->getTag()) && superblock->isValid() &&
121 (is_secure == superblock->isSecure()) &&
122 !superblock->blks[offset]->isValid() &&
130 canCoAllocate(superblock, compressed_size))
123 superblock->isCompressed() &&
124 superblock->canCoAllocate(compressed_size))
131 {
132 victim_superblock = superblock;
133 is_co_allocation = true;
134 break;
135 }
136 }
137
138 // If the superblock is not present or cannot be co-allocated a

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166 }
167
168 return victim;
169}
170
171void
172CompressedTags::insertBlock(const PacketPtr pkt, CacheBlk *blk)
173{
125 {
126 victim_superblock = superblock;
127 is_co_allocation = true;
128 break;
129 }
130 }
131
132 // If the superblock is not present or cannot be co-allocated a

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160 }
161
162 return victim;
163}
164
165void
166CompressedTags::insertBlock(const PacketPtr pkt, CacheBlk *blk)
167{
168 // We check if block can co-allocate before inserting, because this check
169 // assumes the block is still invalid
170 CompressionBlk* compression_blk = static_cast<CompressionBlk*>(blk);
171 const SuperBlk* superblock = static_cast<const SuperBlk*>(
172 compression_blk->getSectorBlock());
173 const bool is_co_allocatable = superblock->isCompressed() &&
174 superblock->canCoAllocate(compression_blk->getSizeBits());
175
174 // Insert block
175 SectorTags::insertBlock(pkt, blk);
176
176 // Insert block
177 SectorTags::insertBlock(pkt, blk);
178
177 // @todo We always store compressed blocks when possible
178 CompressionBlk* compression_blk = static_cast<CompressionBlk*>(blk);
179 compression_blk->setUncompressed();
179 // We always store compressed blocks when possible
180 if (is_co_allocatable) {
181 compression_blk->setCompressed();
182 } else {
183 compression_blk->setUncompressed();
184 }
180}
181
182void
183CompressedTags::forEachBlk(std::function<void(CacheBlk &)> visitor)
184{
185 for (CompressionBlk& blk : blks) {
186 visitor(blk);
187 }

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186
187void
188CompressedTags::forEachBlk(std::function<void(CacheBlk &)> visitor)
189{
190 for (CompressionBlk& blk : blks) {
191 visitor(blk);
192 }

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