stride.hh revision 11439 
1/*
2 * Copyright (c) 2012-2013, 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 * Copyright (c) 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: Ron Dreslinski
41 */
42
43/**
44 * @file
45 * Describes a strided prefetcher.
46 */
47
48#ifndef __MEM_CACHE_PREFETCH_STRIDE_HH__
49#define __MEM_CACHE_PREFETCH_STRIDE_HH__
50
51#include <unordered_map>
52
53#include "mem/cache/prefetch/queued.hh"
54#include "params/StridePrefetcher.hh"
55
56class StridePrefetcher : public QueuedPrefetcher
57{
58  protected:
59    const int maxConf;
60    const int threshConf;
61    const int minConf;
62    const int startConf;
63
64    const int pcTableAssoc;
65    const int pcTableSets;
66
67    const bool useMasterId;
68
69    const int degree;
70
71    struct StrideEntry
72    {
73        StrideEntry() : instAddr(0), lastAddr(0), isSecure(false), stride(0),
74                        confidence(0)
75        { }
76
77        Addr instAddr;
78        Addr lastAddr;
79        bool isSecure;
80        int stride;
81        int confidence;
82    };
83
84    class PCTable
85    {
86      public:
87        PCTable(int assoc, int sets, const std::string name) :
88            pcTableAssoc(assoc), pcTableSets(sets), _name(name) {}
89        StrideEntry** operator[] (int context) {
90            auto it = entries.find(context);
91            if (it != entries.end())
92                return it->second;
93
94            return allocateNewContext(context);
95        }
96
97        ~PCTable();
98      private:
99        const std::string name() {return _name; }
100        const int pcTableAssoc;
101        const int pcTableSets;
102        const std::string _name;
103        std::unordered_map<int, StrideEntry**> entries;
104
105        StrideEntry** allocateNewContext(int context);
106    };
107    PCTable pcTable;
108
109    bool pcTableHit(Addr pc, bool is_secure, int master_id, StrideEntry* &entry);
110    StrideEntry* pcTableVictim(Addr pc, int master_id);
111
112    Addr pcHash(Addr pc) const;
113  public:
114
115    StridePrefetcher(const StridePrefetcherParams *p);
116
117    void calculatePrefetch(const PacketPtr &pkt,
118                           std::vector<AddrPriority> &addresses);
119};
120
121#endif // __MEM_CACHE_PREFETCH_STRIDE_HH__
122