queued.hh revision 13551:f352df8e2863 
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
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 * 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
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
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
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Mitch Hayenga
38 */
39
40#ifndef __MEM_CACHE_PREFETCH_QUEUED_HH__
41#define __MEM_CACHE_PREFETCH_QUEUED_HH__
42
43#include <cstdint>
44#include <list>
45#include <utility>
46
47#include "base/statistics.hh"
48#include "base/types.hh"
49#include "mem/cache/prefetch/base.hh"
50#include "mem/packet.hh"
51
52struct QueuedPrefetcherParams;
53
54class QueuedPrefetcher : public BasePrefetcher
55{
56  protected:
57    struct DeferredPacket {
58        /** Prefetch info corresponding to this packet */
59        PrefetchInfo pfInfo;
60        /** Time when this prefetch becomes ready */
61        Tick tick;
62        /** The memory packet generated by this prefetch */
63        PacketPtr pkt;
64        /** The priority of this prefetch */
65        int32_t priority;
66
67        /**
68         * Constructor
69         * @param pfi PrefechInfo object associated to this packet
70         * @param t Time when this prefetch becomes ready
71         * @param p PacketPtr with the memory request of the prefetch
72         * @param prio This prefetch priority
73         */
74        DeferredPacket(PrefetchInfo const &pfi, Tick t, PacketPtr p,
75                       int32_t prio) : pfInfo(pfi), tick(t), pkt(p),
76                       priority(prio) {
77        }
78
79        bool operator>(const DeferredPacket& that) const
80        {
81            return priority > that.priority;
82        }
83        bool operator<(const DeferredPacket& that) const
84        {
85            return priority < that.priority;
86        }
87        bool operator<=(const DeferredPacket& that) const
88        {
89            return !(*this > that);
90        }
91    };
92    using AddrPriority = std::pair<Addr, int32_t>;
93
94    std::list<DeferredPacket> pfq;
95
96    // PARAMETERS
97
98    /** Maximum size of the prefetch queue */
99    const unsigned queueSize;
100
101    /** Cycles after generation when a prefetch can first be issued */
102    const Cycles latency;
103
104    /** Squash queued prefetch if demand access observed */
105    const bool queueSquash;
106
107    /** Filter prefetches if already queued */
108    const bool queueFilter;
109
110    /** Snoop the cache before generating prefetch (cheating basically) */
111    const bool cacheSnoop;
112
113    /** Tag prefetch with PC of generating access? */
114    const bool tagPrefetch;
115
116    using const_iterator = std::list<DeferredPacket>::const_iterator;
117    const_iterator inPrefetch(const PrefetchInfo &pfi) const;
118    using iterator = std::list<DeferredPacket>::iterator;
119    iterator inPrefetch(const PrefetchInfo &pfi);
120
121    // STATS
122    Stats::Scalar pfIdentified;
123    Stats::Scalar pfBufferHit;
124    Stats::Scalar pfInCache;
125    Stats::Scalar pfRemovedFull;
126    Stats::Scalar pfSpanPage;
127
128  public:
129    QueuedPrefetcher(const QueuedPrefetcherParams *p);
130    virtual ~QueuedPrefetcher();
131
132    void notify(const PacketPtr &pkt, const PrefetchInfo &pfi) override;
133
134    void insert(const PacketPtr &pkt, PrefetchInfo &new_pfi, int32_t priority);
135
136    virtual void calculatePrefetch(const PrefetchInfo &pfi,
137                                   std::vector<AddrPriority> &addresses) = 0;
138    PacketPtr getPacket() override;
139
140    Tick nextPrefetchReadyTime() const override
141    {
142        return pfq.empty() ? MaxTick : pfq.front().tick;
143    }
144
145    void regStats() override;
146};
147
148#endif //__MEM_CACHE_PREFETCH_QUEUED_HH__
149
150