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40 * Authors: Erik Hallnor
46 * Declaration of a common base class for cache tagstore objects.
49 #ifndef __MEM_CACHE_TAGS_BASE_HH__
50 #define __MEM_CACHE_TAGS_BASE_HH__
56 #include "base/callback.hh"
57 #include "base/logging.hh"
58 #include "base/statistics.hh"
59 #include "base/types.hh"
60 #include "mem/cache/blk.hh"
61 #include "params/BaseTags.hh"
62 #include "sim/clocked_object.hh"
66 class ReplaceableEntry;
69 * A common base class of Cache tagstore objects.
71 class BaseTags : public ClockedObject
74 /** The block size of the cache. */
75 const unsigned blkSize;
76 /** Mask out all bits that aren't part of the block offset. */
78 /** The size of the cache. */
80 /** The tag lookup latency of the cache. */
81 const Cycles lookupLatency;
83 * The total access latency of the cache. This latency
84 * is different depending on the cache access mode
85 * (parallel or sequential)
87 const Cycles accessLatency;
88 /** Pointer to the parent cache. */
91 /** Indexing policy */
92 BaseIndexingPolicy *indexingPolicy;
95 * The number of tags that need to be touched to meet the warmup
98 const unsigned warmupBound;
99 /** Marked true when the cache is warmed up. */
102 /** the number of blocks in the cache */
103 const unsigned numBlocks;
105 /** The data blocks, 1 per cache block. */
106 std::unique_ptr<uint8_t[]> dataBlks;
110 * TODO: It would be good if these stats were acquired after warmup.
111 * @addtogroup CacheStatistics
115 /** Per cycle average of the number of tags that hold valid data. */
116 Stats::Average tagsInUse;
118 /** The total number of references to a block before it is replaced. */
119 Stats::Scalar totalRefs;
122 * The number of reference counts sampled. This is different from
123 * replacements because we sample all the valid blocks when the simulator
126 Stats::Scalar sampledRefs;
129 * Average number of references to a block before is was replaced.
130 * @todo This should change to an average stat once we have them.
132 Stats::Formula avgRefs;
134 /** The cycle that the warmup percentage was hit. 0 on failure. */
135 Stats::Scalar warmupCycle;
137 /** Average occupancy of each requestor using the cache */
138 Stats::AverageVector occupancies;
140 /** Average occ % of each requestor using the cache */
141 Stats::Formula avgOccs;
143 /** Occupancy of each context/cpu using the cache */
144 Stats::Vector occupanciesTaskId;
146 /** Occupancy of each context/cpu using the cache */
147 Stats::Vector2d ageTaskId;
149 /** Occ % of each context/cpu using the cache */
150 Stats::Formula percentOccsTaskId;
152 /** Number of tags consulted over all accesses. */
153 Stats::Scalar tagAccesses;
154 /** Number of data blocks consulted over all accesses. */
155 Stats::Scalar dataAccesses;
162 * Set the parent cache back pointer.
164 * @param _cache Pointer to parent cache.
166 void setCache(BaseCache *_cache);
169 typedef BaseTagsParams Params;
170 BaseTags(const Params *p);
175 virtual ~BaseTags() {}
178 * Initialize blocks and set the parent cache back pointer.
180 * @param _cache Pointer to parent cache.
182 virtual void init(BaseCache *_cache) = 0;
185 * Register local statistics.
190 * Average in the reference count for valid blocks when the simulation
196 * Computes stats just prior to dump event
201 * Print all tags used
206 * Finds the block in the cache without touching it.
208 * @param addr The address to look for.
209 * @param is_secure True if the target memory space is secure.
210 * @return Pointer to the cache block.
212 virtual CacheBlk *findBlock(Addr addr, bool is_secure) const;
215 * Find a block given set and way.
217 * @param set The set of the block.
218 * @param way The way of the block.
221 virtual ReplaceableEntry* findBlockBySetAndWay(int set, int way) const;
224 * Align an address to the block size.
225 * @param addr the address to align.
226 * @return The block address.
228 Addr blkAlign(Addr addr) const
230 return addr & ~blkMask;
234 * Calculate the block offset of an address.
235 * @param addr the address to get the offset of.
236 * @return the block offset.
238 int extractBlkOffset(Addr addr) const
240 return (addr & blkMask);
244 * Limit the allocation for the cache ways.
245 * @param ways The maximum number of ways available for replacement.
247 virtual void setWayAllocationMax(int ways)
249 panic("This tag class does not implement way allocation limit!\n");
253 * Get the way allocation mask limit.
254 * @return The maximum number of ways available for replacement.
256 virtual int getWayAllocationMax() const
258 panic("This tag class does not implement way allocation limit!\n");
263 * This function updates the tags when a block is invalidated
265 * @param blk A valid block to invalidate.
267 virtual void invalidate(CacheBlk *blk)
270 assert(blk->isValid());
272 occupancies[blk->srcMasterId]--;
273 totalRefs += blk->refCount;
280 * Find replacement victim based on address. If the address requires
281 * blocks to be evicted, their locations are listed for eviction. If a
282 * conventional cache is being used, the list only contains the victim.
283 * However, if using sector or compressed caches, the victim is one of
284 * the blocks to be evicted, but its location is the only one that will
285 * be assigned to the newly allocated block associated to this address.
288 * @param addr Address to find a victim for.
289 * @param is_secure True if the target memory space is secure.
290 * @param evict_blks Cache blocks to be evicted.
291 * @return Cache block to be replaced.
293 virtual CacheBlk* findVictim(Addr addr, const bool is_secure,
294 std::vector<CacheBlk*>& evict_blks) const = 0;
296 virtual CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) = 0;
299 * Generate the tag from the given address.
301 * @param addr The address to get the tag from.
302 * @return The tag of the address.
304 virtual Addr extractTag(const Addr addr) const;
307 * Insert the new block into the cache and update stats.
309 * @param addr Address of the block.
310 * @param is_secure Whether the block is in secure space or not.
311 * @param src_master_ID The source requestor ID.
312 * @param task_ID The new task ID.
313 * @param blk The block to update.
315 virtual void insertBlock(const Addr addr, const bool is_secure,
316 const int src_master_ID, const uint32_t task_ID,
320 * Regenerate the block address.
322 * @param block The block.
323 * @return the block address.
325 virtual Addr regenerateBlkAddr(const CacheBlk* blk) const = 0;
328 * Visit each block in the tags and apply a visitor
330 * The visitor should be a std::function that takes a cache block
331 * reference as its parameter.
333 * @param visitor Visitor to call on each block.
335 virtual void forEachBlk(std::function<void(CacheBlk &)> visitor) = 0;
338 * Find if any of the blocks satisfies a condition
340 * The visitor should be a std::function that takes a cache block
341 * reference as its parameter. The visitor will terminate the
342 * traversal early if the condition is satisfied.
344 * @param visitor Visitor to call on each block.
346 virtual bool anyBlk(std::function<bool(CacheBlk &)> visitor) = 0;
350 * Update the reference stats using data from the input block
352 * @param blk The input block
354 void cleanupRefsVisitor(CacheBlk &blk);
357 * Update the occupancy and age stats using data from the input block
359 * @param blk The input block
361 void computeStatsVisitor(CacheBlk &blk);
364 class BaseTagsCallback : public Callback
368 BaseTagsCallback(BaseTags *t) : tags(t) {}
369 virtual void process() { tags->cleanupRefs(); };
372 class BaseTagsDumpCallback : public Callback
376 BaseTagsDumpCallback(BaseTags *t) : tags(t) {}
377 virtual void process() { tags->computeStats(); };
380 #endif //__MEM_CACHE_TAGS_BASE_HH__