base.hh revision 13216:6ae030076b29 
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/blk.hh"
61#include "params/BaseTags.hh"
62#include "sim/clocked_object.hh"
63
64class BaseCache;
65class ReplaceableEntry;
66
67/**
68 * A common base class of Cache tagstore objects.
69 */
70class BaseTags : public ClockedObject
71{
72  protected:
73    /** The block size of the cache. */
74    const unsigned blkSize;
75    /** Mask out all bits that aren't part of the block offset. */
76    const Addr blkMask;
77    /** The size of the cache. */
78    const unsigned size;
79    /** The tag lookup latency of the cache. */
80    const Cycles lookupLatency;
81    /**
82     * The total access latency of the cache. This latency
83     * is different depending on the cache access mode
84     * (parallel or sequential)
85     */
86    const Cycles accessLatency;
87    /** Pointer to the parent cache. */
88    BaseCache *cache;
89
90    /**
91     * The number of tags that need to be touched to meet the warmup
92     * percentage.
93     */
94    const unsigned warmupBound;
95    /** Marked true when the cache is warmed up. */
96    bool warmedUp;
97
98    /** the number of blocks in the cache */
99    const unsigned numBlocks;
100
101    /** The data blocks, 1 per cache block. */
102    std::unique_ptr<uint8_t[]> dataBlks;
103
104    // Statistics
105    /**
106     * TODO: It would be good if these stats were acquired after warmup.
107     * @addtogroup CacheStatistics
108     * @{
109     */
110
111    /** Per cycle average of the number of tags that hold valid data. */
112    Stats::Average tagsInUse;
113
114    /** The total number of references to a block before it is replaced. */
115    Stats::Scalar totalRefs;
116
117    /**
118     * The number of reference counts sampled. This is different from
119     * replacements because we sample all the valid blocks when the simulator
120     * exits.
121     */
122    Stats::Scalar sampledRefs;
123
124    /**
125     * Average number of references to a block before is was replaced.
126     * @todo This should change to an average stat once we have them.
127     */
128    Stats::Formula avgRefs;
129
130    /** The cycle that the warmup percentage was hit. 0 on failure. */
131    Stats::Scalar warmupCycle;
132
133    /** Average occupancy of each requestor using the cache */
134    Stats::AverageVector occupancies;
135
136    /** Average occ % of each requestor using the cache */
137    Stats::Formula avgOccs;
138
139    /** Occupancy of each context/cpu using the cache */
140    Stats::Vector occupanciesTaskId;
141
142    /** Occupancy of each context/cpu using the cache */
143    Stats::Vector2d ageTaskId;
144
145    /** Occ % of each context/cpu using the cache */
146    Stats::Formula percentOccsTaskId;
147
148    /** Number of tags consulted over all accesses. */
149    Stats::Scalar tagAccesses;
150    /** Number of data blocks consulted over all accesses. */
151    Stats::Scalar dataAccesses;
152
153    /**
154     * @}
155     */
156
157    /**
158     * Set the parent cache back pointer.
159     *
160     * @param _cache Pointer to parent cache.
161     */
162    void setCache(BaseCache *_cache);
163
164  public:
165    typedef BaseTagsParams Params;
166    BaseTags(const Params *p);
167
168    /**
169     * Destructor.
170     */
171    virtual ~BaseTags() {}
172
173    /**
174     * Initialize blocks and set the parent cache back pointer.
175     *
176     * @param _cache Pointer to parent cache.
177     */
178    virtual void init(BaseCache *_cache) = 0;
179
180    /**
181     * Register local statistics.
182     */
183    void regStats();
184
185    /**
186     * Average in the reference count for valid blocks when the simulation
187     * exits.
188     */
189    void cleanupRefs();
190
191    /**
192     * Computes stats just prior to dump event
193     */
194    void computeStats();
195
196    /**
197     * Print all tags used
198     */
199    std::string print();
200
201    /**
202     * Find a block using the memory address
203     */
204    virtual CacheBlk * findBlock(Addr addr, bool is_secure) const = 0;
205
206    /**
207     * Find a block given set and way.
208     *
209     * @param set The set of the block.
210     * @param way The way of the block.
211     * @return The block.
212     */
213    virtual ReplaceableEntry* findBlockBySetAndWay(int set, int way) const = 0;
214
215    /**
216     * Align an address to the block size.
217     * @param addr the address to align.
218     * @return The block address.
219     */
220    Addr blkAlign(Addr addr) const
221    {
222        return addr & ~blkMask;
223    }
224
225    /**
226     * Calculate the block offset of an address.
227     * @param addr the address to get the offset of.
228     * @return the block offset.
229     */
230    int extractBlkOffset(Addr addr) const
231    {
232        return (addr & blkMask);
233    }
234
235    /**
236     * Limit the allocation for the cache ways.
237     * @param ways The maximum number of ways available for replacement.
238     */
239    virtual void setWayAllocationMax(int ways)
240    {
241        panic("This tag class does not implement way allocation limit!\n");
242    }
243
244    /**
245     * Get the way allocation mask limit.
246     * @return The maximum number of ways available for replacement.
247     */
248    virtual int getWayAllocationMax() const
249    {
250        panic("This tag class does not implement way allocation limit!\n");
251        return -1;
252    }
253
254    /**
255     * This function updates the tags when a block is invalidated
256     *
257     * @param blk A valid block to invalidate.
258     */
259    virtual void invalidate(CacheBlk *blk)
260    {
261        assert(blk);
262        assert(blk->isValid());
263
264        occupancies[blk->srcMasterId]--;
265        totalRefs += blk->refCount;
266        sampledRefs++;
267
268        blk->invalidate();
269    }
270
271    /**
272     * Find replacement victim based on address. If the address requires
273     * blocks to be evicted, their locations are listed for eviction. If a
274     * conventional cache is being used, the list only contains the victim.
275     * However, if using sector or compressed caches, the victim is one of
276     * the blocks to be evicted, but its location is the only one that will
277     * be assigned to the newly allocated block associated to this address.
278     * @sa insertBlock
279     *
280     * @param addr Address to find a victim for.
281     * @param is_secure True if the target memory space is secure.
282     * @param evict_blks Cache blocks to be evicted.
283     * @return Cache block to be replaced.
284     */
285    virtual CacheBlk* findVictim(Addr addr, const bool is_secure,
286                                 std::vector<CacheBlk*>& evict_blks) const = 0;
287
288    virtual CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) = 0;
289
290    virtual Addr extractTag(Addr addr) const = 0;
291
292    /**
293     * Insert the new block into the cache and update stats.
294     *
295     * @param addr Address of the block.
296     * @param is_secure Whether the block is in secure space or not.
297     * @param src_master_ID The source requestor ID.
298     * @param task_ID The new task ID.
299     * @param blk The block to update.
300     */
301    virtual void insertBlock(const Addr addr, const bool is_secure,
302                             const int src_master_ID, const uint32_t task_ID,
303                             CacheBlk *blk);
304
305    /**
306     * Regenerate the block address.
307     *
308     * @param block The block.
309     * @return the block address.
310     */
311    virtual Addr regenerateBlkAddr(const CacheBlk* blk) const = 0;
312
313    /**
314     * Visit each block in the tags and apply a visitor
315     *
316     * The visitor should be a std::function that takes a cache block
317     * reference as its parameter.
318     *
319     * @param visitor Visitor to call on each block.
320     */
321    virtual void forEachBlk(std::function<void(CacheBlk &)> visitor) = 0;
322
323    /**
324     * Find if any of the blocks satisfies a condition
325     *
326     * The visitor should be a std::function that takes a cache block
327     * reference as its parameter. The visitor will terminate the
328     * traversal early if the condition is satisfied.
329     *
330     * @param visitor Visitor to call on each block.
331     */
332    virtual bool anyBlk(std::function<bool(CacheBlk &)> visitor) = 0;
333
334  private:
335    /**
336     * Update the reference stats using data from the input block
337     *
338     * @param blk The input block
339     */
340    void cleanupRefsVisitor(CacheBlk &blk);
341
342    /**
343     * Update the occupancy and age stats using data from the input block
344     *
345     * @param blk The input block
346     */
347    void computeStatsVisitor(CacheBlk &blk);
348};
349
350class BaseTagsCallback : public Callback
351{
352    BaseTags *tags;
353  public:
354    BaseTagsCallback(BaseTags *t) : tags(t) {}
355    virtual void process() { tags->cleanupRefs(); };
356};
357
358class BaseTagsDumpCallback : public Callback
359{
360    BaseTags *tags;
361  public:
362    BaseTagsDumpCallback(BaseTags *t) : tags(t) {}
363    virtual void process() { tags->computeStats(); };
364};
365
366#endif //__MEM_CACHE_TAGS_BASE_HH__
367