queued.hh revision 13416:d90887d0c889 
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
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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        Tick tick;
59        PacketPtr pkt;
60        int32_t priority;
61        DeferredPacket(Tick t, PacketPtr p, int32_t pr) : tick(t), pkt(p),
62                                                        priority(pr)  {}
63        bool operator>(const DeferredPacket& that) const
64        {
65            return priority > that.priority;
66        }
67        bool operator<(const DeferredPacket& that) const
68        {
69            return priority < that.priority;
70        }
71        bool operator<=(const DeferredPacket& that) const
72        {
73            return !(*this > that);
74        }
75    };
76    using AddrPriority = std::pair<Addr, int32_t>;
77
78    std::list<DeferredPacket> pfq;
79
80    // PARAMETERS
81
82    /** Maximum size of the prefetch queue */
83    const unsigned queueSize;
84
85    /** Cycles after generation when a prefetch can first be issued */
86    const Cycles latency;
87
88    /** Squash queued prefetch if demand access observed */
89    const bool queueSquash;
90
91    /** Filter prefetches if already queued */
92    const bool queueFilter;
93
94    /** Snoop the cache before generating prefetch (cheating basically) */
95    const bool cacheSnoop;
96
97    /** Tag prefetch with PC of generating access? */
98    const bool tagPrefetch;
99
100    using const_iterator = std::list<DeferredPacket>::const_iterator;
101    std::list<DeferredPacket>::const_iterator inPrefetch(Addr address,
102            bool is_secure) const;
103    using iterator = std::list<DeferredPacket>::iterator;
104    std::list<DeferredPacket>::iterator inPrefetch(Addr address,
105            bool is_secure);
106
107    // STATS
108    Stats::Scalar pfIdentified;
109    Stats::Scalar pfBufferHit;
110    Stats::Scalar pfInCache;
111    Stats::Scalar pfRemovedFull;
112    Stats::Scalar pfSpanPage;
113
114  public:
115    QueuedPrefetcher(const QueuedPrefetcherParams *p);
116    virtual ~QueuedPrefetcher();
117
118    void notify(const PacketPtr &pkt) override;
119    PacketPtr insert(AddrPriority& info, bool is_secure);
120
121    // Note: This should really be pure virtual, but doesnt go well with params
122    virtual void calculatePrefetch(const PacketPtr &pkt,
123                                   std::vector<AddrPriority> &addresses) = 0;
124    PacketPtr getPacket();
125
126    Tick nextPrefetchReadyTime() const
127    {
128        return pfq.empty() ? MaxTick : pfq.front().tick;
129    }
130
131    void regStats();
132};
133
134#endif //__MEM_CACHE_PREFETCH_QUEUED_HH__
135
136