base.hh revision 12745:e28c117a9806 
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 "mem/packet.hh"
62#include "params/BaseTags.hh"
63#include "sim/clocked_object.hh"
64
65class BaseCache;
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  public:
158    typedef BaseTagsParams Params;
159    BaseTags(const Params *p);
160
161    /**
162     * Destructor.
163     */
164    virtual ~BaseTags() {}
165
166    /**
167     * Set the parent cache back pointer.
168     * @param _cache Pointer to parent cache.
169     */
170    void setCache(BaseCache *_cache);
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     * Find a block using the memory address
195     */
196    virtual CacheBlk * findBlock(Addr addr, bool is_secure) const = 0;
197
198    /**
199     * Find a block given set and way.
200     *
201     * @param set The set of the block.
202     * @param way The way of the block.
203     * @return The block.
204     */
205    virtual ReplaceableEntry* findBlockBySetAndWay(int set, int way) const = 0;
206
207    /**
208     * Align an address to the block size.
209     * @param addr the address to align.
210     * @return The block address.
211     */
212    Addr blkAlign(Addr addr) const
213    {
214        return addr & ~blkMask;
215    }
216
217    /**
218     * Calculate the block offset of an address.
219     * @param addr the address to get the offset of.
220     * @return the block offset.
221     */
222    int extractBlkOffset(Addr addr) const
223    {
224        return (addr & blkMask);
225    }
226
227    /**
228     * Limit the allocation for the cache ways.
229     * @param ways The maximum number of ways available for replacement.
230     */
231    virtual void setWayAllocationMax(int ways)
232    {
233        panic("This tag class does not implement way allocation limit!\n");
234    }
235
236    /**
237     * Get the way allocation mask limit.
238     * @return The maximum number of ways available for replacement.
239     */
240    virtual int getWayAllocationMax() const
241    {
242        panic("This tag class does not implement way allocation limit!\n");
243        return -1;
244    }
245
246    /**
247     * This function updates the tags when a block is invalidated
248     *
249     * @param blk A valid block to invalidate.
250     */
251    virtual void invalidate(CacheBlk *blk)
252    {
253        assert(blk);
254        assert(blk->isValid());
255
256        occupancies[blk->srcMasterId]--;
257        totalRefs += blk->refCount;
258        sampledRefs++;
259
260        blk->invalidate();
261    }
262
263    /**
264     * Find replacement victim based on address. If the address requires
265     * blocks to be evicted, their locations are listed for eviction. If a
266     * conventional cache is being used, the list only contains the victim.
267     * However, if using sector or compressed caches, the victim is one of
268     * the blocks to be evicted, but its location is the only one that will
269     * be assigned to the newly allocated block associated to this address.
270     * @sa insertBlock
271     *
272     * @param addr Address to find a victim for.
273     * @param evict_blks Cache blocks to be evicted.
274     * @return Cache block to be replaced.
275     */
276    virtual CacheBlk* findVictim(Addr addr, std::vector<CacheBlk*>& evict_blks)
277                                                                     const = 0;
278
279    virtual CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) = 0;
280
281    virtual Addr extractTag(Addr addr) const = 0;
282
283    /**
284     * Insert the new block into the cache and update stats.
285     *
286     * @param pkt Packet holding the address to update
287     * @param blk The block to update.
288     */
289    virtual void insertBlock(PacketPtr pkt, CacheBlk *blk);
290
291    /**
292     * Regenerate the block address.
293     *
294     * @param block The block.
295     * @return the block address.
296     */
297    virtual Addr regenerateBlkAddr(const CacheBlk* blk) const = 0;
298
299    /**
300     * Visit each block in the tags and apply a visitor
301     *
302     * The visitor should be a std::function that takes a cache block
303     * reference as its parameter.
304     *
305     * @param visitor Visitor to call on each block.
306     */
307    virtual void forEachBlk(std::function<void(CacheBlk &)> visitor) = 0;
308
309    /**
310     * Find if any of the blocks satisfies a condition
311     *
312     * The visitor should be a std::function that takes a cache block
313     * reference as its parameter. The visitor will terminate the
314     * traversal early if the condition is satisfied.
315     *
316     * @param visitor Visitor to call on each block.
317     */
318    virtual bool anyBlk(std::function<bool(CacheBlk &)> visitor) = 0;
319
320  private:
321    /**
322     * Update the reference stats using data from the input block
323     *
324     * @param blk The input block
325     */
326    void cleanupRefsVisitor(CacheBlk &blk);
327
328    /**
329     * Update the occupancy and age stats using data from the input block
330     *
331     * @param blk The input block
332     */
333    void computeStatsVisitor(CacheBlk &blk);
334};
335
336class BaseTagsCallback : public Callback
337{
338    BaseTags *tags;
339  public:
340    BaseTagsCallback(BaseTags *t) : tags(t) {}
341    virtual void process() { tags->cleanupRefs(); };
342};
343
344class BaseTagsDumpCallback : public Callback
345{
346    BaseTags *tags;
347  public:
348    BaseTagsDumpCallback(BaseTags *t) : tags(t) {}
349    virtual void process() { tags->computeStats(); };
350};
351
352#endif //__MEM_CACHE_TAGS_BASE_HH__
353