queued.hh

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 * Authors: Mitch Hayenga
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#ifndef __MEM_CACHE_PREFETCH_QUEUED_HH__
#define __MEM_CACHE_PREFETCH_QUEUED_HH__

#include <cstdint>
#include <list>
#include <utility>

#include "base/statistics.hh"
#include "base/types.hh"
#include "mem/cache/prefetch/base.hh"
#include "mem/packet.hh"

struct QueuedPrefetcherParams;

class QueuedPrefetcher : public BasePrefetcher
{
  protected:
    struct DeferredPacket : public BaseTLB::Translation {
        QueuedPrefetcher *owner;
        PrefetchInfo pfInfo;
        Tick tick;
        PacketPtr pkt;
        int32_t priority;
        RequestPtr translationRequest;
        ThreadContext *tc;
        bool ongoingTranslation;

        DeferredPacket(QueuedPrefetcher *o, PrefetchInfo const &pfi, Tick t,
            int32_t prio) : owner(o), pfInfo(pfi), tick(t), pkt(nullptr),
            priority(prio), translationRequest(), tc(nullptr),
            ongoingTranslation(false) {
        }

        bool operator>(const DeferredPacket& that) const
        {
            return priority > that.priority;
        }
        bool operator<(const DeferredPacket& that) const
        {
            return priority < that.priority;
        }
        bool operator<=(const DeferredPacket& that) const
        {
            return !(*this > that);
        }

        void createPkt(Addr paddr, unsigned blk_size, MasterID mid,
                       bool tag_prefetch, Tick t);

        void setTranslationRequest(const RequestPtr &req)
        {
            translationRequest = req;
        }

        void markDelayed() override
        {}

        void finish(const Fault &fault, const RequestPtr &req,
                            ThreadContext *tc, BaseTLB::Mode mode) override;

        void startTranslation(BaseTLB *tlb);
    };

    std::list<DeferredPacket> pfq;
    std::list<DeferredPacket> pfqMissingTranslation;

    using const_iterator = std::list<DeferredPacket>::const_iterator;
    using iterator = std::list<DeferredPacket>::iterator;

    // PARAMETERS

    const unsigned queueSize;

    const unsigned missingTranslationQueueSize;

    const Cycles latency;

    const bool queueSquash;

    const bool queueFilter;

    const bool cacheSnoop;

    const bool tagPrefetch;

    const unsigned int throttleControlPct;

    // STATS
    Stats::Scalar pfIdentified;
    Stats::Scalar pfBufferHit;
    Stats::Scalar pfInCache;
    Stats::Scalar pfRemovedFull;
    Stats::Scalar pfSpanPage;

  public:
    using AddrPriority = std::pair<Addr, int32_t>;

    QueuedPrefetcher(const QueuedPrefetcherParams *p);
    virtual ~QueuedPrefetcher();

    void notify(const PacketPtr &pkt, const PrefetchInfo &pfi) override;

    void insert(const PacketPtr &pkt, PrefetchInfo &new_pfi, int32_t priority);

    virtual void calculatePrefetch(const PrefetchInfo &pfi,
                                   std::vector<AddrPriority> &addresses) = 0;
    PacketPtr getPacket() override;

    Tick nextPrefetchReadyTime() const override
    {
        return pfq.empty() ? MaxTick : pfq.front().tick;
    }

    void regStats() override;

  private:

    void addToQueue(std::list<DeferredPacket> &queue, DeferredPacket &dpp);

    void processMissingTranslations(unsigned max);

    void translationComplete(DeferredPacket *dp, bool failed);

    bool alreadyInQueue(std::list<DeferredPacket> &queue,
                        const PrefetchInfo &pfi, int32_t priority);

    size_t getMaxPermittedPrefetches(size_t total) const;

    RequestPtr createPrefetchRequest(Addr addr, PrefetchInfo const &pfi,
                                        PacketPtr pkt);
};

#endif //__MEM_CACHE_PREFETCH_QUEUED_HH__