stride.hh

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/*
 * Copyright (c) 2018 Inria
 * Copyright (c) 2012-2013, 2015 ARM Limited
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 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
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#ifndef __MEM_CACHE_PREFETCH_STRIDE_HH__
#define __MEM_CACHE_PREFETCH_STRIDE_HH__

#include <string>
#include <unordered_map>
#include <vector>

#include "base/sat_counter.hh"
#include "base/types.hh"
#include "mem/cache/prefetch/associative_set.hh"
#include "mem/cache/prefetch/queued.hh"
#include "mem/cache/replacement_policies/replaceable_entry.hh"
#include "mem/cache/tags/indexing_policies/set_associative.hh"
#include "mem/packet.hh"
#include "params/StridePrefetcherHashedSetAssociative.hh"

class BaseIndexingPolicy;
class BaseReplacementPolicy;
struct StridePrefetcherParams;

namespace Prefetcher {

class StridePrefetcherHashedSetAssociative : public SetAssociative
{
  protected:
    uint32_t extractSet(const Addr addr) const override;
    Addr extractTag(const Addr addr) const override;

  public:
    StridePrefetcherHashedSetAssociative(
        const StridePrefetcherHashedSetAssociativeParams *p)
      : SetAssociative(p)
    {
    }
    ~StridePrefetcherHashedSetAssociative() = default;
};

class Stride : public Queued
{
  protected:
    const SatCounter initConfidence;

    const double threshConf;

    const bool useMasterId;

    const int degree;

    const struct PCTableInfo
    {
        const int assoc;
        const int numEntries;

        BaseIndexingPolicy* const indexingPolicy;
        BaseReplacementPolicy* const replacementPolicy;

        PCTableInfo(int assoc, int num_entries,
            BaseIndexingPolicy* indexing_policy,
            BaseReplacementPolicy* replacement_policy)
          : assoc(assoc), numEntries(num_entries),
            indexingPolicy(indexing_policy),
            replacementPolicy(replacement_policy)
        {
        }
    } pcTableInfo;

    struct StrideEntry : public TaggedEntry
    {
        StrideEntry(const SatCounter& init_confidence);

        void invalidate() override;

        Addr lastAddr;
        int stride;
        SatCounter confidence;
    };
    typedef AssociativeSet<StrideEntry> PCTable;
    std::unordered_map<int, PCTable> pcTables;

    PCTable* findTable(int context);

    PCTable* allocateNewContext(int context);

  public:
    Stride(const StridePrefetcherParams *p);

    void calculatePrefetch(const PrefetchInfo &pfi,
                           std::vector<AddrPriority> &addresses) override;
};

} // namespace Prefetcher

#endif // __MEM_CACHE_PREFETCH_STRIDE_HH__