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/*
* Copyright (c) 2013-2014 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* 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
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file
* Miss and writeback queue declarations.
*/
#ifndef __MEM_CACHE_PREFETCH_BASE_HH__
#define __MEM_CACHE_PREFETCH_BASE_HH__
#include <cstdint>
#include "arch/generic/tlb.hh"
#include "base/compiler.hh"
#include "base/statistics.hh"
#include "base/types.hh"
#include "mem/cache/cache_blk.hh"
#include "mem/packet.hh"
#include "mem/request.hh"
#include "sim/byteswap.hh"
#include "sim/clocked_object.hh"
#include "sim/probe/probe.hh"
namespace gem5
{
class BaseCache;
struct BasePrefetcherParams;
namespace prefetch
{
class Base : public ClockedObject
{
class PrefetchListener : public ProbeListenerArgBase<PacketPtr>
{
public:
PrefetchListener(Base &_parent, ProbeManager *pm,
const std::string &name, bool _isFill = false,
bool _miss = false)
: ProbeListenerArgBase(pm, name),
parent(_parent), isFill(_isFill), miss(_miss) {}
void notify(const PacketPtr &pkt) override;
protected:
Base &parent;
const bool isFill;
const bool miss;
};
std::vector<PrefetchListener *> listeners;
public:
/**
* Class containing the information needed by the prefetch to train and
* generate new prefetch requests.
*/
class PrefetchInfo
{
/** The address used to train and generate prefetches */
Addr address;
/** The program counter that generated this address. */
Addr pc;
/** The requestor ID that generated this address. */
RequestorID requestorId;
/** Validity bit for the PC of this address. */
bool validPC;
/** Whether this address targets the secure memory space. */
bool secure;
/** Size in bytes of the request triggering this event */
unsigned int size;
/** Whether this event comes from a write request */
bool write;
/** Physical address, needed because address can be virtual */
Addr paddress;
/** Whether this event comes from a cache miss */
bool cacheMiss;
/** Pointer to the associated request data */
uint8_t *data;
public:
/**
* Obtains the address value of this Prefetcher address.
* @return the addres value.
*/
Addr getAddr() const
{
return address;
}
/**
* Returns true if the address targets the secure memory space.
* @return true if the address targets the secure memory space.
*/
bool isSecure() const
{
return secure;
}
/**
* Returns the program counter that generated this request.
* @return the pc value
*/
Addr getPC() const
{
assert(hasPC());
return pc;
}
/**
* Returns true if the associated program counter is valid
* @return true if the program counter has a valid value
*/
bool hasPC() const
{
return validPC;
}
/**
* Gets the requestor ID that generated this address
* @return the requestor ID that generated this address
*/
RequestorID getRequestorId() const
{
return requestorId;
}
/**
* Gets the size of the request triggering this event
* @return the size in bytes of the request triggering this event
*/
unsigned int getSize() const
{
return size;
}
/**
* Checks if the request that caused this prefetch event was a write
* request
* @return true if the request causing this event is a write request
*/
bool isWrite() const
{
return write;
}
/**
* Gets the physical address of the request
* @return physical address of the request
*/
Addr getPaddr() const
{
return paddress;
}
/**
* Check if this event comes from a cache miss
* @result true if this event comes from a cache miss
*/
bool isCacheMiss() const
{
return cacheMiss;
}
/**
* Gets the associated data of the request triggering the event
* @param Byte ordering of the stored data
* @return the data
*/
template <typename T>
inline T
get(ByteOrder endian) const
{
if (data == nullptr) {
panic("PrefetchInfo::get called with a request with no data.");
}
switch (endian) {
case ByteOrder::big:
return betoh(*(T*)data);
case ByteOrder::little:
return letoh(*(T*)data);
default:
panic("Illegal byte order in PrefetchInfo::get()\n");
};
}
/**
* Check for equality
* @param pfi PrefetchInfo to compare against
* @return True if this object and the provided one are equal
*/
bool sameAddr(PrefetchInfo const &pfi) const
{
return this->getAddr() == pfi.getAddr() &&
this->isSecure() == pfi.isSecure();
}
/**
* Constructs a PrefetchInfo using a PacketPtr.
* @param pkt PacketPtr used to generate the PrefetchInfo
* @param addr the address value of the new object, this address is
* used to train the prefetcher
* @param miss whether this event comes from a cache miss
*/
PrefetchInfo(PacketPtr pkt, Addr addr, bool miss);
/**
* Constructs a PrefetchInfo using a new address value and
* another PrefetchInfo as a reference.
* @param pfi PrefetchInfo used to generate this new object
* @param addr the address value of the new object
*/
PrefetchInfo(PrefetchInfo const &pfi, Addr addr);
~PrefetchInfo()
{
delete[] data;
}
};
protected:
// PARAMETERS
/** Pointr to the parent cache. */
BaseCache* cache;
/** The block size of the parent cache. */
unsigned blkSize;
/** log_2(block size of the parent cache). */
unsigned lBlkSize;
/** Only consult prefetcher on cache misses? */
const bool onMiss;
/** Consult prefetcher on reads? */
const bool onRead;
/** Consult prefetcher on reads? */
const bool onWrite;
/** Consult prefetcher on data accesses? */
const bool onData;
/** Consult prefetcher on instruction accesses? */
const bool onInst;
/** Request id for prefetches */
const RequestorID requestorId;
const Addr pageBytes;
/** Prefetch on every access, not just misses */
const bool prefetchOnAccess;
/** Prefetch on hit on prefetched lines */
const bool prefetchOnPfHit;
/** Use Virtual Addresses for prefetching */
const bool useVirtualAddresses;
/**
* Determine if this access should be observed
* @param pkt The memory request causing the event
* @param miss whether this event comes from a cache miss
*/
bool observeAccess(const PacketPtr &pkt, bool miss) const;
/** Determine if address is in cache */
bool inCache(Addr addr, bool is_secure) const;
/** Determine if address is in cache miss queue */
bool inMissQueue(Addr addr, bool is_secure) const;
bool hasBeenPrefetched(Addr addr, bool is_secure) const;
/** Determine if addresses are on the same page */
bool samePage(Addr a, Addr b) const;
/** Determine the address of the block in which a lays */
Addr blockAddress(Addr a) const;
/** Determine the address of a at block granularity */
Addr blockIndex(Addr a) const;
/** Determine the address of the page in which a lays */
Addr pageAddress(Addr a) const;
/** Determine the page-offset of a */
Addr pageOffset(Addr a) const;
/** Build the address of the i-th block inside the page */
Addr pageIthBlockAddress(Addr page, uint32_t i) const;
struct StatGroup : public statistics::Group
{
StatGroup(statistics::Group *parent);
statistics::Scalar demandMshrMisses;
statistics::Scalar pfIssued;
/** The number of times a HW-prefetched block is evicted w/o
* reference. */
statistics::Scalar pfUnused;
/** The number of times a HW-prefetch is useful. */
statistics::Scalar pfUseful;
/** The number of times there is a hit on prefetch but cache block
* is not in an usable state */
statistics::Scalar pfUsefulButMiss;
statistics::Formula accuracy;
statistics::Formula coverage;
/** The number of times a HW-prefetch hits in cache. */
statistics::Scalar pfHitInCache;
/** The number of times a HW-prefetch hits in a MSHR. */
statistics::Scalar pfHitInMSHR;
/** The number of times a HW-prefetch hits
* in the Write Buffer (WB). */
statistics::Scalar pfHitInWB;
/** The number of times a HW-prefetch is late
* (hit in cache, MSHR, WB). */
statistics::Formula pfLate;
} prefetchStats;
/** Total prefetches issued */
uint64_t issuedPrefetches;
/** Total prefetches that has been useful */
uint64_t usefulPrefetches;
/** Registered mmu for address translations */
BaseMMU * mmu;
public:
Base(const BasePrefetcherParams &p);
virtual ~Base() = default;
virtual void setCache(BaseCache *_cache);
/**
* Notify prefetcher of cache access (may be any access or just
* misses, depending on cache parameters.)
*/
virtual void notify(const PacketPtr &pkt, const PrefetchInfo &pfi) = 0;
/** Notify prefetcher of cache fill */
virtual void notifyFill(const PacketPtr &pkt)
{}
virtual PacketPtr getPacket() = 0;
virtual Tick nextPrefetchReadyTime() const = 0;
void
prefetchUnused()
{
prefetchStats.pfUnused++;
}
void
incrDemandMhsrMisses()
{
prefetchStats.demandMshrMisses++;
}
void
pfHitInCache()
{
prefetchStats.pfHitInCache++;
}
void
pfHitInMSHR()
{
prefetchStats.pfHitInMSHR++;
}
void
pfHitInWB()
{
prefetchStats.pfHitInWB++;
}
/**
* Register probe points for this object.
*/
void regProbeListeners() override;
/**
* Process a notification event from the ProbeListener.
* @param pkt The memory request causing the event
* @param miss whether this event comes from a cache miss
*/
void probeNotify(const PacketPtr &pkt, bool miss);
/**
* Add a SimObject and a probe name to listen events from
* @param obj The SimObject pointer to listen from
* @param name The probe name
*/
void addEventProbe(SimObject *obj, const char *name);
/**
* Add a BaseMMU object to be used whenever a translation is needed.
* This is generally required when the prefetcher is allowed to generate
* page crossing references and/or uses virtual addresses for training.
* @param mmu pointer to the BaseMMU object to add
*/
void addMMU(BaseMMU *mmu);
};
} // namespace prefetch
} // namespace gem5
#endif //__MEM_CACHE_PREFETCH_BASE_HH__