lru_rp.hh revision 12600:e670dd17c8cf 
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 Least Recently Used replacement policy.
34 * The victim is chosen using the timestamp. The timestamp may be true or
35 * pseudo, depending on the quantity of bits allocated for that.
36 */
37
38#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_LRU_RP_HH__
39#define __MEM_CACHE_REPLACEMENT_POLICIES_LRU_RP_HH__
40
41#include "mem/cache/replacement_policies/base.hh"
42#include "params/LRURP.hh"
43
44class LRURP : public BaseReplacementPolicy
45{
46  public:
47    /** Convenience typedef. */
48    typedef LRURPParams Params;
49
50    /**
51     * Construct and initiliaze this replacement policy.
52     */
53    LRURP(const Params *p);
54
55    /**
56     * Destructor.
57     */
58    ~LRURP() {}
59
60    /**
61     * Touch a block to update its last touch tick.
62     *
63     * @param blk Cache block to be touched.
64     */
65    void touch(CacheBlk *blk);
66
67    /**
68     * Reset replacement data for a block. Used when a block is inserted.
69     * Sets its last touch tick as the current tick.
70     *
71     * @param blk Cache block to be reset.
72     */
73    void reset(CacheBlk *blk);
74
75    /**
76     * Find replacement victim using LRU timestamps.
77     *
78     * @param candidates Replacement candidates, selected by indexing policy.
79     * @return Cache block to be replaced.
80     */
81    CacheBlk* getVictim(const ReplacementCandidates& candidates) override;
82};
83
84#endif // __MEM_CACHE_REPLACEMENT_POLICIES_LRU_RP_HH__
85