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;
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: Daniel Carvalho
29 */
30
31/**
32 * @file
33 * Declaration of a compressed set associative tag store using superblocks.
34 */
35
36#ifndef __MEM_CACHE_TAGS_COMPRESSED_TAGS_HH__
37#define __MEM_CACHE_TAGS_COMPRESSED_TAGS_HH__
38
39#include <vector>
40
41#include "mem/cache/tags/sector_tags.hh"
42#include "mem/cache/tags/super_blk.hh"
43
44class BaseCache;
| 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;
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: Daniel Carvalho
29 */
30
31/**
32 * @file
33 * Declaration of a compressed set associative tag store using superblocks.
34 */
35
36#ifndef __MEM_CACHE_TAGS_COMPRESSED_TAGS_HH__
37#define __MEM_CACHE_TAGS_COMPRESSED_TAGS_HH__
38
39#include <vector>
40
41#include "mem/cache/tags/sector_tags.hh"
42#include "mem/cache/tags/super_blk.hh"
43
44class BaseCache;
|
45struct CompressedTagsParams;
46
47/**
48 * A CompressedTags cache tag store.
49 * @sa \ref gem5MemorySystem "gem5 Memory System"
50 *
51 * The Compression Ratio (CR) of a superblock is defined by
52 * CR = uncompressed_size / compressed_size.
53 *
54 * The CompressedTags placement policy divides the cache into s sets of w
55 * superblocks (ways). Each superblock can then contain up to CR compressed
56 * blocks.
57 *
58 * For each tag entry there can be multiple data blocks. We have the same
59 * number of tags a conventional cache would have, but we instantiate the
60 * maximum number of data blocks (according to the compression ratio) per
61 * tag, to virtually implement compression without increasing the complexity
62 * of the simulator.
63 *
64 * This is a simple implementation of cache compression, where superblocks
65 * can only have at most numBlocksPerSector compressed blocks, each compressed
66 * to at least (100/numBlocksPerSector)% of its size.
67 *
68 * numBlocksPerSector holds the maximum number of blocks a superblock with
69 * the best possible compression factor would hold. It is equivalent to CR
70 * from the previous definition.
71 */
72class CompressedTags : public SectorTags
73{
74 private:
75 /** The cache blocks. */
76 std::vector<CompressionBlk> blks;
77 /** The cache superblocks. */
78 std::vector<SuperBlk> superBlks;
79
80 public:
81 /** Convenience typedef. */
82 typedef CompressedTagsParams Params;
83
84 /**
85 * Construct and initialize this tag store.
86 */
87 CompressedTags(const Params *p);
88
89 /**
90 * Destructor.
91 */
92 virtual ~CompressedTags() {};
93
94 /**
95 * Initialize blocks as SuperBlk and CompressionBlk instances.
96 */
97 void tagsInit() override;
98
99 /**
| 46struct CompressedTagsParams;
47
48/**
49 * A CompressedTags cache tag store.
50 * @sa \ref gem5MemorySystem "gem5 Memory System"
51 *
52 * The Compression Ratio (CR) of a superblock is defined by
53 * CR = uncompressed_size / compressed_size.
54 *
55 * The CompressedTags placement policy divides the cache into s sets of w
56 * superblocks (ways). Each superblock can then contain up to CR compressed
57 * blocks.
58 *
59 * For each tag entry there can be multiple data blocks. We have the same
60 * number of tags a conventional cache would have, but we instantiate the
61 * maximum number of data blocks (according to the compression ratio) per
62 * tag, to virtually implement compression without increasing the complexity
63 * of the simulator.
64 *
65 * This is a simple implementation of cache compression, where superblocks
66 * can only have at most numBlocksPerSector compressed blocks, each compressed
67 * to at least (100/numBlocksPerSector)% of its size.
68 *
69 * numBlocksPerSector holds the maximum number of blocks a superblock with
70 * the best possible compression factor would hold. It is equivalent to CR
71 * from the previous definition.
72 */
73class CompressedTags : public SectorTags
74{
75 private:
76 /** The cache blocks. */
77 std::vector<CompressionBlk> blks;
78 /** The cache superblocks. */
79 std::vector<SuperBlk> superBlks;
80
81 public:
82 /** Convenience typedef. */
83 typedef CompressedTagsParams Params;
84
85 /**
86 * Construct and initialize this tag store.
87 */
88 CompressedTags(const Params *p);
89
90 /**
91 * Destructor.
92 */
93 virtual ~CompressedTags() {};
94
95 /**
96 * Initialize blocks as SuperBlk and CompressionBlk instances.
97 */
98 void tagsInit() override;
99
100 /**
|
| 101 * Checks whether a superblock can co-allocate given compressed data block.
102 *
103 * @param superblock Superblock to check.
104 * @param compressed_size Size, in bits, of new block to allocate.
105 * @return True if block can be co-allocated in superblock.
106 */
107 bool canCoAllocate(const SuperBlk* superblock,
108 const std::size_t compressed_size) const;
109
110 /**
111 * Find replacement victim based on address. Checks if data can be co-
112 * allocated before choosing blocks to be evicted.
113 *
114 * @param addr Address to find a victim for.
115 * @param is_secure True if the target memory space is secure.
116 * @param compressed_size Size, in bits, of new block to allocate.
117 * @param evict_blks Cache blocks to be evicted.
118 * @return Cache block to be replaced.
119 */
120 CacheBlk* findVictim(Addr addr, const bool is_secure,
121 const std::size_t compressed_size,
122 std::vector<CacheBlk*>& evict_blks) const override;
123
124 /**
|
100 * Insert the new block into the cache and update replacement data.
101 *
102 * @param pkt Packet holding the address to update
103 * @param blk The block to update.
104 */
105 void insertBlock(const PacketPtr pkt, CacheBlk *blk) override;
106
107 /**
108 * Visit each sub-block in the tags and apply a visitor.
109 *
110 * The visitor should be a std::function that takes a cache block.
111 * reference as its parameter.
112 *
113 * @param visitor Visitor to call on each block.
114 */
115 void forEachBlk(std::function<void(CacheBlk &)> visitor) override;
116
117 /**
118 * Find if any of the sub-blocks satisfies a condition.
119 *
120 * The visitor should be a std::function that takes a cache block
121 * reference as its parameter. The visitor will terminate the
122 * traversal early if the condition is satisfied.
123 *
124 * @param visitor Visitor to call on each block.
125 */
126 bool anyBlk(std::function<bool(CacheBlk &)> visitor) override;
127};
128
129#endif //__MEM_CACHE_TAGS_COMPRESSED_TAGS_HH__
| 125 * Insert the new block into the cache and update replacement data.
126 *
127 * @param pkt Packet holding the address to update
128 * @param blk The block to update.
129 */
130 void insertBlock(const PacketPtr pkt, CacheBlk *blk) override;
131
132 /**
133 * Visit each sub-block in the tags and apply a visitor.
134 *
135 * The visitor should be a std::function that takes a cache block.
136 * reference as its parameter.
137 *
138 * @param visitor Visitor to call on each block.
139 */
140 void forEachBlk(std::function<void(CacheBlk &)> visitor) override;
141
142 /**
143 * Find if any of the sub-blocks satisfies a condition.
144 *
145 * The visitor should be a std::function that takes a cache block
146 * reference as its parameter. The visitor will terminate the
147 * traversal early if the condition is satisfied.
148 *
149 * @param visitor Visitor to call on each block.
150 */
151 bool anyBlk(std::function<bool(CacheBlk &)> visitor) override;
152};
153
154#endif //__MEM_CACHE_TAGS_COMPRESSED_TAGS_HH__
|