1/*
2 * Copyright (c) 2012-2014,2016-2018 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 * Copyright (c) 2003-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Erik Hallnor
41 * Ron Dreslinski
42 */
43
44/**
45 * @file
46 * Declaration of a common base class for cache tagstore objects.
47 */
48
49#ifndef __MEM_CACHE_TAGS_BASE_HH__
50#define __MEM_CACHE_TAGS_BASE_HH__
51
52#include <cassert>
53#include <functional>
54#include <string>
55
56#include "base/callback.hh"
57#include "base/logging.hh"
58#include "base/statistics.hh"
59#include "base/types.hh"
60#include "mem/cache/cache_blk.hh"
61#include "params/BaseTags.hh"
62#include "sim/clocked_object.hh"
63
64class System;
65class IndexingPolicy;
66class ReplaceableEntry;
67
68/**
69 * A common base class of Cache tagstore objects.
70 */
71class BaseTags : public ClockedObject
72{
73 protected:
74 /** The block size of the cache. */
75 const unsigned blkSize;
76 /** Mask out all bits that aren't part of the block offset. */
77 const Addr blkMask;
78 /** The size of the cache. */
79 const unsigned size;
80 /** The tag lookup latency of the cache. */
81 const Cycles lookupLatency;
82
83 /** System we are currently operating in. */
84 System *system;
85
86 /** Indexing policy */
87 BaseIndexingPolicy *indexingPolicy;
88
89 /**
90 * The number of tags that need to be touched to meet the warmup
91 * percentage.
92 */
93 const unsigned warmupBound;
94 /** Marked true when the cache is warmed up. */
95 bool warmedUp;
96
97 /** the number of blocks in the cache */
98 const unsigned numBlocks;
99
100 /** The data blocks, 1 per cache block. */
101 std::unique_ptr<uint8_t[]> dataBlks;
102
103 // Statistics
104 /**
105 * TODO: It would be good if these stats were acquired after warmup.
106 * @addtogroup CacheStatistics
107 * @{
108 */
109
110 /** Per cycle average of the number of tags that hold valid data. */
111 Stats::Average tagsInUse;
112
113 /** The total number of references to a block before it is replaced. */
114 Stats::Scalar totalRefs;
115
116 /**
117 * The number of reference counts sampled. This is different from
118 * replacements because we sample all the valid blocks when the simulator
119 * exits.
120 */
121 Stats::Scalar sampledRefs;
122
123 /**
124 * Average number of references to a block before is was replaced.
125 * @todo This should change to an average stat once we have them.
126 */
127 Stats::Formula avgRefs;
128
129 /** The cycle that the warmup percentage was hit. 0 on failure. */
130 Stats::Scalar warmupCycle;
131
132 /** Average occupancy of each requestor using the cache */
133 Stats::AverageVector occupancies;
134
135 /** Average occ % of each requestor using the cache */
136 Stats::Formula avgOccs;
137
138 /** Occupancy of each context/cpu using the cache */
139 Stats::Vector occupanciesTaskId;
140
141 /** Occupancy of each context/cpu using the cache */
142 Stats::Vector2d ageTaskId;
143
144 /** Occ % of each context/cpu using the cache */
145 Stats::Formula percentOccsTaskId;
146
147 /** Number of tags consulted over all accesses. */
148 Stats::Scalar tagAccesses;
149 /** Number of data blocks consulted over all accesses. */
150 Stats::Scalar dataAccesses;
151
152 /**
153 * @}
154 */
155
156 public:
157 typedef BaseTagsParams Params;
158 BaseTags(const Params *p);
159
160 /**
161 * Destructor.
162 */
163 virtual ~BaseTags() {}
164
165 /**
166 * Initialize blocks. Must be overriden by every subclass that uses
167 * a block type different from its parent's, as the current Python
168 * code generation does not allow templates.
169 */
170 virtual void tagsInit() = 0;
171
172 /**
173 * Register local statistics.
174 */
175 void regStats();
176
177 /**
178 * Average in the reference count for valid blocks when the simulation
179 * exits.
180 */
181 void cleanupRefs();
182
183 /**
184 * Computes stats just prior to dump event
185 */
186 void computeStats();
187
188 /**
189 * Print all tags used
190 */
191 std::string print();
192
193 /**
194 * Finds the block in the cache without touching it.
195 *
196 * @param addr The address to look for.
197 * @param is_secure True if the target memory space is secure.
198 * @return Pointer to the cache block.
199 */
200 virtual CacheBlk *findBlock(Addr addr, bool is_secure) const;
201
202 /**
203 * Find a block given set and way.
204 *
205 * @param set The set of the block.
206 * @param way The way of the block.
207 * @return The block.
208 */
209 virtual ReplaceableEntry* findBlockBySetAndWay(int set, int way) const;
210
211 /**
212 * Align an address to the block size.
213 * @param addr the address to align.
214 * @return The block address.
215 */
216 Addr blkAlign(Addr addr) const
217 {
218 return addr & ~blkMask;
219 }
220
221 /**
222 * Calculate the block offset of an address.
223 * @param addr the address to get the offset of.
224 * @return the block offset.
225 */
226 int extractBlkOffset(Addr addr) const
227 {
228 return (addr & blkMask);
229 }
230
231 /**
232 * Limit the allocation for the cache ways.
233 * @param ways The maximum number of ways available for replacement.
234 */
235 virtual void setWayAllocationMax(int ways)
236 {
237 panic("This tag class does not implement way allocation limit!\n");
238 }
239
240 /**
241 * Get the way allocation mask limit.
242 * @return The maximum number of ways available for replacement.
243 */
244 virtual int getWayAllocationMax() const
245 {
246 panic("This tag class does not implement way allocation limit!\n");
247 return -1;
248 }
249
250 /**
251 * This function updates the tags when a block is invalidated
252 *
253 * @param blk A valid block to invalidate.
254 */
255 virtual void invalidate(CacheBlk *blk)
256 {
257 assert(blk);
258 assert(blk->isValid());
259
260 occupancies[blk->srcMasterId]--;
261 totalRefs += blk->refCount;
262 sampledRefs++;
263
264 blk->invalidate();
265 }
266
267 /**
268 * Find replacement victim based on address. If the address requires
269 * blocks to be evicted, their locations are listed for eviction. If a
270 * conventional cache is being used, the list only contains the victim.
271 * However, if using sector or compressed caches, the victim is one of
272 * the blocks to be evicted, but its location is the only one that will
273 * be assigned to the newly allocated block associated to this address.
274 * @sa insertBlock
275 *
276 * @param addr Address to find a victim for.
277 * @param is_secure True if the target memory space is secure.
278 * @param evict_blks Cache blocks to be evicted.
279 * @return Cache block to be replaced.
280 */
281 virtual CacheBlk* findVictim(Addr addr, const bool is_secure,
282 std::vector<CacheBlk*>& evict_blks) const = 0;
283
284 /**
285 * Access block and update replacement data. May not succeed, in which case
286 * nullptr is returned. This has all the implications of a cache access and
287 * should only be used as such. Returns the tag lookup latency as a side
288 * effect.
289 *
290 * @param addr The address to find.
291 * @param is_secure True if the target memory space is secure.
292 * @param lat The latency of the tag lookup.
293 * @return Pointer to the cache block if found.
294 */
295 virtual CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) = 0;
296
297 /**
298 * Generate the tag from the given address.
299 *
300 * @param addr The address to get the tag from.
301 * @return The tag of the address.
302 */
303 virtual Addr extractTag(const Addr addr) const;
304
305 /**
306 * Insert the new block into the cache and update stats.
307 *
308 * @param addr Address of the block.
309 * @param is_secure Whether the block is in secure space or not.
310 * @param src_master_ID The source requestor ID.
311 * @param task_ID The new task ID.
312 * @param blk The block to update.
313 */
314 virtual void insertBlock(const Addr addr, const bool is_secure,
315 const int src_master_ID, const uint32_t task_ID,
316 CacheBlk *blk);
317
318 /**
319 * Regenerate the block address.
320 *
321 * @param block The block.
322 * @return the block address.
323 */
324 virtual Addr regenerateBlkAddr(const CacheBlk* blk) const = 0;
325
326 /**
327 * Visit each block in the tags and apply a visitor
328 *
329 * The visitor should be a std::function that takes a cache block
330 * reference as its parameter.
331 *
332 * @param visitor Visitor to call on each block.
333 */
334 virtual void forEachBlk(std::function<void(CacheBlk &)> visitor) = 0;
335
336 /**
337 * Find if any of the blocks satisfies a condition
338 *
339 * The visitor should be a std::function that takes a cache block
340 * reference as its parameter. The visitor will terminate the
341 * traversal early if the condition is satisfied.
342 *
343 * @param visitor Visitor to call on each block.
344 */
345 virtual bool anyBlk(std::function<bool(CacheBlk &)> visitor) = 0;
346
347 private:
348 /**
349 * Update the reference stats using data from the input block
350 *
351 * @param blk The input block
352 */
353 void cleanupRefsVisitor(CacheBlk &blk);
354
355 /**
356 * Update the occupancy and age stats using data from the input block
357 *
358 * @param blk The input block
359 */
360 void computeStatsVisitor(CacheBlk &blk);
361};
362
363class BaseTagsCallback : public Callback
364{
365 BaseTags *tags;
366 public:
367 BaseTagsCallback(BaseTags *t) : tags(t) {}
368 virtual void process() { tags->cleanupRefs(); };
369};
370
371class BaseTagsDumpCallback : public Callback
372{
373 BaseTags *tags;
374 public:
375 BaseTagsDumpCallback(BaseTags *t) : tags(t) {}
376 virtual void process() { tags->computeStats(); };
377};
378
379#endif //__MEM_CACHE_TAGS_BASE_HH__