7da851d1a8
This patch does some minor tidying up of the MSHR and MSHRQueue. The clean up started as part of some ad-hoc tracing and debugging, but seems worthwhile enough to go in as a separate patch. The highlights of the changes are reduced scoping (private) members where possible, avoiding redundant new/delete, and constructor initialisation to please static code analyzers.
304 lines
8.9 KiB
C++
304 lines
8.9 KiB
C++
/*
|
|
* Copyright (c) 2012-2013 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) 2002-2005 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.
|
|
*
|
|
* Authors: Erik Hallnor
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* Miss Status and Handling Register (MSHR) declaration.
|
|
*/
|
|
|
|
#ifndef __MSHR_HH__
|
|
#define __MSHR_HH__
|
|
|
|
#include <list>
|
|
|
|
#include "base/printable.hh"
|
|
#include "mem/packet.hh"
|
|
|
|
class CacheBlk;
|
|
class MSHRQueue;
|
|
|
|
/**
|
|
* Miss Status and handling Register. This class keeps all the information
|
|
* needed to handle a cache miss including a list of target requests.
|
|
* @sa \ref gem5MemorySystem "gem5 Memory System"
|
|
*/
|
|
class MSHR : public Packet::SenderState, public Printable
|
|
{
|
|
|
|
/**
|
|
* Consider the MSHRQueue a friend to avoid making everything public
|
|
*/
|
|
friend class MSHRQueue;
|
|
|
|
private:
|
|
|
|
/** Cycle when ready to issue */
|
|
Tick readyTime;
|
|
|
|
/** True if the request is uncacheable */
|
|
bool _isUncacheable;
|
|
|
|
/** Flag set by downstream caches */
|
|
bool downstreamPending;
|
|
|
|
/** Will we have a dirty copy after this request? */
|
|
bool pendingDirty;
|
|
|
|
/** Did we snoop an invalidate while waiting for data? */
|
|
bool postInvalidate;
|
|
|
|
/** Did we snoop a read while waiting for data? */
|
|
bool postDowngrade;
|
|
|
|
public:
|
|
|
|
class Target {
|
|
public:
|
|
|
|
enum Source {
|
|
FromCPU,
|
|
FromSnoop,
|
|
FromPrefetcher
|
|
};
|
|
|
|
Tick recvTime; //!< Time when request was received (for stats)
|
|
Tick readyTime; //!< Time when request is ready to be serviced
|
|
Counter order; //!< Global order (for memory consistency mgmt)
|
|
PacketPtr pkt; //!< Pending request packet.
|
|
Source source; //!< Did request come from cpu, memory, or prefetcher?
|
|
bool markedPending; //!< Did we mark upstream MSHR
|
|
//!< as downstreamPending?
|
|
|
|
Target(PacketPtr _pkt, Tick _readyTime, Counter _order,
|
|
Source _source, bool _markedPending)
|
|
: recvTime(curTick()), readyTime(_readyTime), order(_order),
|
|
pkt(_pkt), source(_source), markedPending(_markedPending)
|
|
{}
|
|
};
|
|
|
|
class TargetList : public std::list<Target> {
|
|
/** Target list iterator. */
|
|
typedef std::list<Target>::iterator Iterator;
|
|
typedef std::list<Target>::const_iterator ConstIterator;
|
|
|
|
public:
|
|
bool needsExclusive;
|
|
bool hasUpgrade;
|
|
|
|
TargetList();
|
|
void resetFlags() { needsExclusive = hasUpgrade = false; }
|
|
bool isReset() { return !needsExclusive && !hasUpgrade; }
|
|
void add(PacketPtr pkt, Tick readyTime, Counter order,
|
|
Target::Source source, bool markPending);
|
|
void replaceUpgrades();
|
|
void clearDownstreamPending();
|
|
bool checkFunctional(PacketPtr pkt);
|
|
void print(std::ostream &os, int verbosity,
|
|
const std::string &prefix) const;
|
|
};
|
|
|
|
/** A list of MSHRs. */
|
|
typedef std::list<MSHR *> List;
|
|
/** MSHR list iterator. */
|
|
typedef List::iterator Iterator;
|
|
/** MSHR list const_iterator. */
|
|
typedef List::const_iterator ConstIterator;
|
|
|
|
/** Pointer to queue containing this MSHR. */
|
|
MSHRQueue *queue;
|
|
|
|
/** Order number assigned by the miss queue. */
|
|
Counter order;
|
|
|
|
/** Address of the request. */
|
|
Addr addr;
|
|
|
|
/** Size of the request. */
|
|
int size;
|
|
|
|
/** True if the request has been sent to the bus. */
|
|
bool inService;
|
|
|
|
/** True if the request is just a simple forward from an upper level */
|
|
bool isForward;
|
|
|
|
/** The pending* and post* flags are only valid if inService is
|
|
* true. Using the accessor functions lets us detect if these
|
|
* flags are accessed improperly.
|
|
*/
|
|
|
|
/** True if we need to get an exclusive copy of the block. */
|
|
bool needsExclusive() const { return targets.needsExclusive; }
|
|
|
|
bool isPendingDirty() const {
|
|
assert(inService); return pendingDirty;
|
|
}
|
|
|
|
bool hasPostInvalidate() const {
|
|
assert(inService); return postInvalidate;
|
|
}
|
|
|
|
bool hasPostDowngrade() const {
|
|
assert(inService); return postDowngrade;
|
|
}
|
|
|
|
/** Thread number of the miss. */
|
|
ThreadID threadNum;
|
|
|
|
private:
|
|
|
|
/** Data buffer (if needed). Currently used only for pending
|
|
* upgrade handling. */
|
|
uint8_t *data;
|
|
|
|
/**
|
|
* Pointer to this MSHR on the ready list.
|
|
* @sa MissQueue, MSHRQueue::readyList
|
|
*/
|
|
Iterator readyIter;
|
|
|
|
/**
|
|
* Pointer to this MSHR on the allocated list.
|
|
* @sa MissQueue, MSHRQueue::allocatedList
|
|
*/
|
|
Iterator allocIter;
|
|
|
|
/** List of all requests that match the address */
|
|
TargetList targets;
|
|
|
|
TargetList deferredTargets;
|
|
|
|
public:
|
|
|
|
bool isUncacheable() const { return _isUncacheable; }
|
|
|
|
/**
|
|
* Allocate a miss to this MSHR.
|
|
* @param cmd The requesting command.
|
|
* @param addr The address of the miss.
|
|
* @param asid The address space id of the miss.
|
|
* @param size The number of bytes to request.
|
|
* @param pkt The original miss.
|
|
*/
|
|
void allocate(Addr addr, int size, PacketPtr pkt,
|
|
Tick when, Counter _order);
|
|
|
|
bool markInService(PacketPtr pkt);
|
|
|
|
void clearDownstreamPending();
|
|
|
|
/**
|
|
* Mark this MSHR as free.
|
|
*/
|
|
void deallocate();
|
|
|
|
/**
|
|
* Add a request to the list of targets.
|
|
* @param target The target.
|
|
*/
|
|
void allocateTarget(PacketPtr target, Tick when, Counter order);
|
|
bool handleSnoop(PacketPtr target, Counter order);
|
|
|
|
/** A simple constructor. */
|
|
MSHR();
|
|
|
|
/**
|
|
* Returns the current number of allocated targets.
|
|
* @return The current number of allocated targets.
|
|
*/
|
|
int getNumTargets() const
|
|
{ return targets.size() + deferredTargets.size(); }
|
|
|
|
/**
|
|
* Returns true if there are targets left.
|
|
* @return true if there are targets
|
|
*/
|
|
bool hasTargets() const { return !targets.empty(); }
|
|
|
|
/**
|
|
* Returns a reference to the first target.
|
|
* @return A pointer to the first target.
|
|
*/
|
|
Target *getTarget()
|
|
{
|
|
assert(hasTargets());
|
|
return &targets.front();
|
|
}
|
|
|
|
/**
|
|
* Pop first target.
|
|
*/
|
|
void popTarget()
|
|
{
|
|
targets.pop_front();
|
|
}
|
|
|
|
bool isForwardNoResponse() const
|
|
{
|
|
if (getNumTargets() != 1)
|
|
return false;
|
|
const Target *tgt = &targets.front();
|
|
return tgt->source == Target::FromCPU && !tgt->pkt->needsResponse();
|
|
}
|
|
|
|
bool promoteDeferredTargets();
|
|
|
|
void handleFill(Packet *pkt, CacheBlk *blk);
|
|
|
|
bool checkFunctional(PacketPtr pkt);
|
|
|
|
/**
|
|
* Prints the contents of this MSHR for debugging.
|
|
*/
|
|
void print(std::ostream &os,
|
|
int verbosity = 0,
|
|
const std::string &prefix = "") const;
|
|
/**
|
|
* A no-args wrapper of print(std::ostream...) meant to be
|
|
* invoked from DPRINTFs avoiding string overheads in fast mode
|
|
*
|
|
* @return string with mshr fields + [deferred]targets
|
|
*/
|
|
std::string print() const;
|
|
};
|
|
|
|
#endif //__MSHR_HH__
|