queued.hh revision 11439:d0368996f1e0 
1/*
2 * Copyright (c) 2014-2015 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
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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 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
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21 * neither the name of the copyright holders nor the names of its
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23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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36 *
37 * Authors: Mitch Hayenga
38 */
39
40#ifndef __MEM_CACHE_PREFETCH_QUEUED_HH__
41#define __MEM_CACHE_PREFETCH_QUEUED_HH__
42
43#include <list>
44
45#include "mem/cache/prefetch/base.hh"
46#include "params/QueuedPrefetcher.hh"
47
48class QueuedPrefetcher : public BasePrefetcher
49{
50  protected:
51    struct DeferredPacket {
52        Tick tick;
53        PacketPtr pkt;
54        int32_t priority;
55        DeferredPacket(Tick t, PacketPtr p, int32_t pr) : tick(t), pkt(p),
56                                                        priority(pr)  {}
57        bool operator>(const DeferredPacket& that) const
58        {
59            return priority > that.priority;
60        }
61        bool operator<(const DeferredPacket& that) const
62        {
63            return priority < that.priority;
64        }
65        bool operator<=(const DeferredPacket& that) const
66        {
67            return !(*this > that);
68        }
69    };
70    using AddrPriority = std::pair<Addr, int32_t>;
71
72    std::list<DeferredPacket> pfq;
73
74    // PARAMETERS
75
76    /** Maximum size of the prefetch queue */
77    const unsigned queueSize;
78
79    /** Cycles after generation when a prefetch can first be issued */
80    const Cycles latency;
81
82    /** Squash queued prefetch if demand access observed */
83    const bool queueSquash;
84
85    /** Filter prefetches if already queued */
86    const bool queueFilter;
87
88    /** Snoop the cache before generating prefetch (cheating basically) */
89    const bool cacheSnoop;
90
91    /** Tag prefetch with PC of generating access? */
92    const bool tagPrefetch;
93
94    using const_iterator = std::list<DeferredPacket>::const_iterator;
95    std::list<DeferredPacket>::const_iterator inPrefetch(Addr address,
96            bool is_secure) const;
97    using iterator = std::list<DeferredPacket>::iterator;
98    std::list<DeferredPacket>::iterator inPrefetch(Addr address,
99            bool is_secure);
100
101    // STATS
102    Stats::Scalar pfIdentified;
103    Stats::Scalar pfBufferHit;
104    Stats::Scalar pfInCache;
105    Stats::Scalar pfRemovedFull;
106    Stats::Scalar pfSpanPage;
107
108  public:
109    QueuedPrefetcher(const QueuedPrefetcherParams *p);
110    virtual ~QueuedPrefetcher();
111
112    Tick notify(const PacketPtr &pkt);
113    PacketPtr insert(AddrPriority& info, bool is_secure);
114
115    // Note: This should really be pure virtual, but doesnt go well with params
116    virtual void calculatePrefetch(const PacketPtr &pkt,
117                                   std::vector<AddrPriority> &addresses) = 0;
118    PacketPtr getPacket();
119
120    Tick nextPrefetchReadyTime() const
121    {
122        return pfq.empty() ? MaxTick : pfq.front().tick;
123    }
124
125    void regStats();
126};
127
128#endif //__MEM_CACHE_PREFETCH_QUEUED_HH__
129
130