stride.hh revision 13424:1744211c9a65 
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 <string>
52#include <unordered_map>
53#include <vector>
54
55#include "base/types.hh"
56#include "mem/cache/prefetch/queued.hh"
57#include "mem/packet.hh"
58
59struct StridePrefetcherParams;
60
61class StridePrefetcher : public QueuedPrefetcher
62{
63  protected:
64    const int maxConf;
65    const int threshConf;
66    const int minConf;
67    const int startConf;
68
69    const int pcTableAssoc;
70    const int pcTableSets;
71
72    const bool useMasterId;
73
74    const int degree;
75
76    struct StrideEntry
77    {
78        StrideEntry() : instAddr(0), lastAddr(0), isSecure(false), stride(0),
79                        confidence(0)
80        { }
81
82        Addr instAddr;
83        Addr lastAddr;
84        bool isSecure;
85        int stride;
86        int confidence;
87    };
88
89    class PCTable
90    {
91      public:
92        PCTable(int assoc, int sets, const std::string name) :
93            pcTableAssoc(assoc), pcTableSets(sets), _name(name) {}
94
95        std::vector<std::vector<StrideEntry>>& operator[] (int context) {
96            auto it = entries.find(context);
97            if (it != entries.end())
98                return it->second;
99
100            return allocateNewContext(context);
101        }
102
103        ~PCTable();
104      private:
105        const std::string name() {return _name; }
106        const int pcTableAssoc;
107        const int pcTableSets;
108        const std::string _name;
109        std::unordered_map<int, std::vector<std::vector<StrideEntry>>> entries;
110
111        std::vector<std::vector<StrideEntry>>& allocateNewContext(int context);
112    };
113    PCTable pcTable;
114
115    /**
116     * Search for an entry in the pc table.
117     *
118     * @param pc The PC to look for.
119     * @param is_secure True if the target memory space is secure.
120     * @param master_id The context.
121     * @return Pointer to the entry.
122     */
123    StrideEntry* findEntry(Addr pc, bool is_secure, int master_id);
124
125    StrideEntry* pcTableVictim(Addr pc, int master_id);
126
127    Addr pcHash(Addr pc) const;
128  public:
129
130    StridePrefetcher(const StridePrefetcherParams *p);
131
132    void calculatePrefetch(const PacketPtr &pkt,
133                           std::vector<AddrPriority> &addresses) override;
134};
135
136#endif // __MEM_CACHE_PREFETCH_STRIDE_HH__
137