gem5  v21.1.0.2
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gem5::memory::MemInterface Class Referenceabstract

General interface to memory device Includes functions and parameters shared across media types. More...

#include <mem_interface.hh>

Inheritance diagram for gem5::memory::MemInterface:
gem5::memory::AbstractMemory gem5::ClockedObject gem5::SimObject gem5::Clocked gem5::EventManager gem5::Serializable gem5::Drainable gem5::statistics::Group gem5::Named gem5::memory::DRAMInterface gem5::memory::NVMInterface

Classes

class  Bank
 A basic class to track the bank state, i.e. More...
 

Public Types

typedef MemInterfaceParams Params
 
- Public Types inherited from gem5::ClockedObject
using Params = ClockedObjectParams
 Parameters of ClockedObject. More...
 
- Public Types inherited from gem5::SimObject
typedef SimObjectParams Params
 

Public Member Functions

void setCtrl (MemCtrl *_ctrl, unsigned int command_window)
 Set a pointer to the controller and initialize interface based on controller parameters. More...
 
Addr getCtrlAddr (Addr addr)
 Get an address in a dense range which starts from 0. More...
 
virtual void setupRank (const uint8_t rank, const bool is_read)=0
 Setup the rank based on packet received. More...
 
virtual bool allRanksDrained () const =0
 Check drain state of interface. More...
 
virtual std::pair< MemPacketQueue::iterator, TickchooseNextFRFCFS (MemPacketQueue &queue, Tick min_col_at) const =0
 For FR-FCFS policy, find first command that can issue Function will be overriden by interface to select based on media characteristics, used to determine when read or write can issue. More...
 
virtual Tick accessLatency () const =0
 
uint32_t bytesPerBurst () const
 
virtual Tick commandOffset () const =0
 
virtual bool burstReady (MemPacket *pkt) const =0
 Check if a burst operation can be issued to the interface. More...
 
Tick rankDelay () const
 Determine the required delay for an access to a different rank. More...
 
Tick minReadToWriteDataGap () const
 
Tick minWriteToReadDataGap () const
 
MemPacketdecodePacket (const PacketPtr pkt, Addr pkt_addr, unsigned int size, bool is_read, bool is_dram)
 Address decoder to figure out physical mapping onto ranks, banks, and rows. More...
 
virtual void addRankToRankDelay (Tick cmd_at)=0
 Add rank to rank delay to bus timing to all banks in all ranks when access to an alternate interface is issued. More...
 
 MemInterface (const Params &_p)
 
- Public Member Functions inherited from gem5::memory::AbstractMemory
 PARAMS (AbstractMemory)
 
 AbstractMemory (const Params &p)
 
virtual ~AbstractMemory ()
 
void initState () override
 initState() is called on each SimObject when not restoring from a checkpoint. More...
 
bool isNull () const
 See if this is a null memory that should never store data and always return zero. More...
 
void setBackingStore (uint8_t *pmem_addr)
 Set the host memory backing store to be used by this memory controller. More...
 
void getBackdoor (MemBackdoorPtr &bd_ptr)
 
const std::list< LockedAddr > & getLockedAddrList () const
 Get the list of locked addresses to allow checkpointing. More...
 
void addLockedAddr (LockedAddr addr)
 Add a locked address to allow for checkpointing. More...
 
Systemsystem () const
 read the system pointer Implemented for completeness with the setter More...
 
void system (System *sys)
 Set the system pointer on this memory This can't be done via a python parameter because the system needs pointers to all the memories and the reverse would create a cycle in the object graph. More...
 
AddrRange getAddrRange () const
 Get the address range. More...
 
uint8_t * toHostAddr (Addr addr) const
 Transform a gem5 address space address into its physical counterpart in the host address space. More...
 
uint64_t size () const
 Get the memory size. More...
 
Addr start () const
 Get the start address. More...
 
bool isConfReported () const
 Should this memory be passed to the kernel and part of the OS physical memory layout. More...
 
bool isInAddrMap () const
 Some memories are used as shadow memories or should for other reasons not be part of the global address map. More...
 
bool isKvmMap () const
 When shadow memories are in use, KVM may want to make one or the other, but cannot map both into the guest address space. More...
 
void access (PacketPtr pkt)
 Perform an untimed memory access and update all the state (e.g. More...
 
void functionalAccess (PacketPtr pkt)
 Perform an untimed memory read or write without changing anything but the memory itself. More...
 
- Public Member Functions inherited from gem5::ClockedObject
 ClockedObject (const ClockedObjectParams &p)
 
void serialize (CheckpointOut &cp) const override
 Serialize an object. More...
 
void unserialize (CheckpointIn &cp) override
 Unserialize an object. More...
 
- Public Member Functions inherited from gem5::SimObject
const Paramsparams () const
 
 SimObject (const Params &p)
 
virtual ~SimObject ()
 
virtual void init ()
 init() is called after all C++ SimObjects have been created and all ports are connected. More...
 
virtual void loadState (CheckpointIn &cp)
 loadState() is called on each SimObject when restoring from a checkpoint. More...
 
virtual void regProbePoints ()
 Register probe points for this object. More...
 
virtual void regProbeListeners ()
 Register probe listeners for this object. More...
 
ProbeManagergetProbeManager ()
 Get the probe manager for this object. More...
 
virtual PortgetPort (const std::string &if_name, PortID idx=InvalidPortID)
 Get a port with a given name and index. More...
 
virtual void startup ()
 startup() is the final initialization call before simulation. More...
 
DrainState drain () override
 Provide a default implementation of the drain interface for objects that don't need draining. More...
 
virtual void memWriteback ()
 Write back dirty buffers to memory using functional writes. More...
 
virtual void memInvalidate ()
 Invalidate the contents of memory buffers. More...
 
void serialize (CheckpointOut &cp) const override
 Serialize an object. More...
 
void unserialize (CheckpointIn &cp) override
 Unserialize an object. More...
 
- Public Member Functions inherited from gem5::EventManager
EventQueueeventQueue () const
 
void schedule (Event &event, Tick when)
 
void deschedule (Event &event)
 
void reschedule (Event &event, Tick when, bool always=false)
 
void schedule (Event *event, Tick when)
 
void deschedule (Event *event)
 
void reschedule (Event *event, Tick when, bool always=false)
 
void wakeupEventQueue (Tick when=(Tick) -1)
 This function is not needed by the usual gem5 event loop but may be necessary in derived EventQueues which host gem5 on other schedulers. More...
 
void setCurTick (Tick newVal)
 
 EventManager (EventManager &em)
 Event manger manages events in the event queue. More...
 
 EventManager (EventManager *em)
 
 EventManager (EventQueue *eq)
 
- Public Member Functions inherited from gem5::Serializable
 Serializable ()
 
virtual ~Serializable ()
 
void serializeSection (CheckpointOut &cp, const char *name) const
 Serialize an object into a new section. More...
 
void serializeSection (CheckpointOut &cp, const std::string &name) const
 
void unserializeSection (CheckpointIn &cp, const char *name)
 Unserialize an a child object. More...
 
void unserializeSection (CheckpointIn &cp, const std::string &name)
 
- Public Member Functions inherited from gem5::Drainable
DrainState drainState () const
 Return the current drain state of an object. More...
 
virtual void notifyFork ()
 Notify a child process of a fork. More...
 
- Public Member Functions inherited from gem5::statistics::Group
 Group (Group *parent, const char *name=nullptr)
 Construct a new statistics group. More...
 
virtual ~Group ()
 
virtual void regStats ()
 Callback to set stat parameters. More...
 
virtual void resetStats ()
 Callback to reset stats. More...
 
virtual void preDumpStats ()
 Callback before stats are dumped. More...
 
void addStat (statistics::Info *info)
 Register a stat with this group. More...
 
const std::map< std::string, Group * > & getStatGroups () const
 Get all child groups associated with this object. More...
 
const std::vector< Info * > & getStats () const
 Get all stats associated with this object. More...
 
void addStatGroup (const char *name, Group *block)
 Add a stat block as a child of this block. More...
 
const InforesolveStat (std::string name) const
 Resolve a stat by its name within this group. More...
 
void mergeStatGroup (Group *block)
 Merge the contents (stats & children) of a block to this block. More...
 
 Group ()=delete
 
 Group (const Group &)=delete
 
Groupoperator= (const Group &)=delete
 
- Public Member Functions inherited from gem5::Named
 Named (const std::string &name_)
 
virtual ~Named ()=default
 
virtual std::string name () const
 
- Public Member Functions inherited from gem5::Clocked
void updateClockPeriod ()
 Update the tick to the current tick. More...
 
Tick clockEdge (Cycles cycles=Cycles(0)) const
 Determine the tick when a cycle begins, by default the current one, but the argument also enables the caller to determine a future cycle. More...
 
Cycles curCycle () const
 Determine the current cycle, corresponding to a tick aligned to a clock edge. More...
 
Tick nextCycle () const
 Based on the clock of the object, determine the start tick of the first cycle that is at least one cycle in the future. More...
 
uint64_t frequency () const
 
Tick clockPeriod () const
 
double voltage () const
 
Cycles ticksToCycles (Tick t) const
 
Tick cyclesToTicks (Cycles c) const
 

Public Attributes

const uint32_t readBufferSize
 Buffer sizes for read and write queues in the controller These are passed to the controller on instantiation Defining them here allows for buffers to be resized based on memory type / configuration. More...
 
const uint32_t writeBufferSize
 
- Public Attributes inherited from gem5::ClockedObject
PowerStatepowerState
 

Protected Member Functions

virtual Tick writeToReadDelay () const
 
Tick readToWriteDelay () const
 
Tick rankToRankDelay () const
 
- Protected Member Functions inherited from gem5::memory::AbstractMemory
bool checkLockedAddrList (PacketPtr pkt)
 
void trackLoadLocked (PacketPtr pkt)
 
bool writeOK (PacketPtr pkt)
 
- Protected Member Functions inherited from gem5::Drainable
 Drainable ()
 
virtual ~Drainable ()
 
virtual void drainResume ()
 Resume execution after a successful drain. More...
 
void signalDrainDone () const
 Signal that an object is drained. More...
 
- Protected Member Functions inherited from gem5::Clocked
 Clocked (ClockDomain &clk_domain)
 Create a clocked object and set the clock domain based on the parameters. More...
 
 Clocked (Clocked &)=delete
 
Clockedoperator= (Clocked &)=delete
 
virtual ~Clocked ()
 Virtual destructor due to inheritance. More...
 
void resetClock () const
 Reset the object's clock using the current global tick value. More...
 
virtual void clockPeriodUpdated ()
 A hook subclasses can implement so they can do any extra work that's needed when the clock rate is changed. More...
 

Protected Attributes

MemCtrlctrl
 A pointer to the parent MemCtrl instance. More...
 
unsigned int maxCommandsPerWindow
 Number of commands that can issue in the defined controller command window, used to verify command bandwidth. More...
 
enums::AddrMap addrMapping
 Memory controller configuration initialized based on parameter values. More...
 
const uint32_t burstSize
 General device and channel characteristics The rowsPerBank is determined based on the capacity, number of ranks and banks, the burst size, and the row buffer size. More...
 
const uint32_t deviceSize
 
const uint32_t deviceRowBufferSize
 
const uint32_t devicesPerRank
 
const uint32_t rowBufferSize
 
const uint32_t burstsPerRowBuffer
 
const uint32_t burstsPerStripe
 
const uint32_t ranksPerChannel
 
const uint32_t banksPerRank
 
uint32_t rowsPerBank
 
const GEM5_CLASS_VAR_USED Tick tCK
 General timing requirements. More...
 
const Tick tCS
 
const Tick tBURST
 
const Tick tRTW
 
const Tick tWTR
 
- Protected Attributes inherited from gem5::memory::AbstractMemory
AddrRange range
 
uint8_t * pmemAddr
 
MemBackdoor backdoor
 
const bool confTableReported
 
const bool inAddrMap
 
const bool kvmMap
 
std::list< LockedAddrlockedAddrList
 
System_system
 Pointer to the System object. More...
 
gem5::memory::AbstractMemory::MemStats stats
 
- Protected Attributes inherited from gem5::SimObject
const SimObjectParams & _params
 Cached copy of the object parameters. More...
 
- Protected Attributes inherited from gem5::EventManager
EventQueueeventq
 A pointer to this object's event queue. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from gem5::SimObject
static void serializeAll (const std::string &cpt_dir)
 Create a checkpoint by serializing all SimObjects in the system. More...
 
static SimObjectfind (const char *name)
 Find the SimObject with the given name and return a pointer to it. More...
 
static void setSimObjectResolver (SimObjectResolver *resolver)
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
static SimObjectResolvergetSimObjectResolver ()
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
- Static Public Member Functions inherited from gem5::Serializable
static const std::string & currentSection ()
 Gets the fully-qualified name of the active section. More...
 
static void generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
 Generate a checkpoint file so that the serialization can be routed to it. More...
 

Detailed Description

General interface to memory device Includes functions and parameters shared across media types.

Definition at line 77 of file mem_interface.hh.

Member Typedef Documentation

◆ Params

typedef MemInterfaceParams gem5::memory::MemInterface::Params

Definition at line 298 of file mem_interface.hh.

Constructor & Destructor Documentation

◆ MemInterface()

gem5::memory::MemInterface::MemInterface ( const Params _p)

Definition at line 60 of file mem_interface.cc.

Member Function Documentation

◆ accessLatency()

virtual Tick gem5::memory::MemInterface::accessLatency ( ) const
pure virtual

◆ addRankToRankDelay()

virtual void gem5::memory::MemInterface::addRankToRankDelay ( Tick  cmd_at)
pure virtual

Add rank to rank delay to bus timing to all banks in all ranks when access to an alternate interface is issued.

param cmd_at Time of current command used as starting point for addition of rank-to-rank delay

Implemented in gem5::memory::NVMInterface, and gem5::memory::DRAMInterface.

◆ allRanksDrained()

virtual bool gem5::memory::MemInterface::allRanksDrained ( ) const
pure virtual

Check drain state of interface.

Returns
true if all ranks are drained and idle

Implemented in gem5::memory::NVMInterface, and gem5::memory::DRAMInterface.

◆ burstReady()

virtual bool gem5::memory::MemInterface::burstReady ( MemPacket pkt) const
pure virtual

Check if a burst operation can be issued to the interface.

Parameters
Returntrue if RD/WR can issue

Implemented in gem5::memory::NVMInterface, and gem5::memory::DRAMInterface.

◆ bytesPerBurst()

uint32_t gem5::memory::MemInterface::bytesPerBurst ( ) const
inline

◆ chooseNextFRFCFS()

virtual std::pair<MemPacketQueue::iterator, Tick> gem5::memory::MemInterface::chooseNextFRFCFS ( MemPacketQueue queue,
Tick  min_col_at 
) const
pure virtual

For FR-FCFS policy, find first command that can issue Function will be overriden by interface to select based on media characteristics, used to determine when read or write can issue.

Parameters
queueQueued requests to consider
min_col_atMinimum tick for 'seamless' issue
Returns
an iterator to the selected packet, else queue.end()
the tick when the packet selected will issue

Implemented in gem5::memory::NVMInterface, and gem5::memory::DRAMInterface.

◆ commandOffset()

virtual Tick gem5::memory::MemInterface::commandOffset ( ) const
pure virtual

◆ decodePacket()

MemPacket * gem5::memory::MemInterface::decodePacket ( const PacketPtr  pkt,
Addr  pkt_addr,
unsigned int  size,
bool  is_read,
bool  is_dram 
)

Address decoder to figure out physical mapping onto ranks, banks, and rows.

This function is called multiple times on the same system packet if the pakcet is larger than burst of the memory. The pkt_addr is used for the offset within the packet.

Parameters
pktThe packet from the outside world
pkt_addrThe starting address of the packet
sizeThe size of the packet in bytes
is_readIs the request for a read or a write to memory
is_dramIs the request to a DRAM interface
Returns
A MemPacket pointer with the decoded information

Definition at line 89 of file mem_interface.cc.

References gem5::X86ISA::addr, addrMapping, banksPerRank, burstSize, burstsPerRowBuffer, burstsPerStripe, DPRINTF, getCtrlAddr(), gem5::memory::MemInterface::Bank::NO_ROW, panic, ranksPerChannel, rowsPerBank, and gem5::memory::AbstractMemory::size().

Referenced by gem5::memory::MemCtrl::addToReadQueue(), and gem5::memory::MemCtrl::addToWriteQueue().

◆ getCtrlAddr()

Addr gem5::memory::MemInterface::getCtrlAddr ( Addr  addr)
inline

Get an address in a dense range which starts from 0.

The input address is the physical address of the request in an address space that contains other SimObjects apart from this controller.

Parameters
addrThe intput address which should be in the addrRange
Returns
An address in the continues range [0, max)

Definition at line 200 of file mem_interface.hh.

References gem5::X86ISA::addr, gem5::AddrRange::getOffset(), and gem5::memory::AbstractMemory::range.

Referenced by decodePacket().

◆ minReadToWriteDataGap()

Tick gem5::memory::MemInterface::minReadToWriteDataGap ( ) const
inline
Returns
minimum additional bus turnaround required for read-to-write

Definition at line 265 of file mem_interface.hh.

References tCS, and tRTW.

Referenced by gem5::memory::MemCtrl::minReadToWriteDataGap().

◆ minWriteToReadDataGap()

Tick gem5::memory::MemInterface::minWriteToReadDataGap ( ) const
inline
Returns
minimum additional bus turnaround required for write-to-read

Definition at line 271 of file mem_interface.hh.

References tCS, and tWTR.

Referenced by gem5::memory::MemCtrl::minWriteToReadDataGap().

◆ rankDelay()

Tick gem5::memory::MemInterface::rankDelay ( ) const
inline

Determine the required delay for an access to a different rank.

Returns
required rank to rank delay

Definition at line 259 of file mem_interface.hh.

References tCS.

◆ rankToRankDelay()

Tick gem5::memory::MemInterface::rankToRankDelay ( ) const
inlineprotected

◆ readToWriteDelay()

Tick gem5::memory::MemInterface::readToWriteDelay ( ) const
inlineprotected

◆ setCtrl()

void gem5::memory::MemInterface::setCtrl ( MemCtrl _ctrl,
unsigned int  command_window 
)

Set a pointer to the controller and initialize interface based on controller parameters.

Parameters
_ctrlpointer to the parent controller
command_windowsize of command window used to check command bandwidth

Definition at line 82 of file mem_interface.cc.

References ctrl, maxCommandsPerWindow, and tCK.

◆ setupRank()

virtual void gem5::memory::MemInterface::setupRank ( const uint8_t  rank,
const bool  is_read 
)
pure virtual

Setup the rank based on packet received.

Parameters
integervalue of rank to be setup. used to index ranks vector
arewe setting up rank for read or write packet?

Implemented in gem5::memory::NVMInterface, and gem5::memory::DRAMInterface.

◆ writeToReadDelay()

virtual Tick gem5::memory::MemInterface::writeToReadDelay ( ) const
inlineprotectedvirtual

Reimplemented in gem5::memory::DRAMInterface.

Definition at line 159 of file mem_interface.hh.

References tBURST, and tWTR.

Referenced by gem5::memory::NVMInterface::doBurstAccess().

Member Data Documentation

◆ addrMapping

enums::AddrMap gem5::memory::MemInterface::addrMapping
protected

Memory controller configuration initialized based on parameter values.

Definition at line 129 of file mem_interface.hh.

Referenced by decodePacket(), and gem5::memory::DRAMInterface::init().

◆ banksPerRank

const uint32_t gem5::memory::MemInterface::banksPerRank
protected

◆ burstSize

const uint32_t gem5::memory::MemInterface::burstSize
protected

General device and channel characteristics The rowsPerBank is determined based on the capacity, number of ranks and banks, the burst size, and the row buffer size.

Definition at line 136 of file mem_interface.hh.

Referenced by bytesPerBurst(), gem5::memory::NVMInterface::chooseRead(), decodePacket(), gem5::memory::DRAMInterface::doBurstAccess(), gem5::memory::NVMInterface::doBurstAccess(), and gem5::memory::DRAMInterface::DRAMInterface().

◆ burstsPerRowBuffer

const uint32_t gem5::memory::MemInterface::burstsPerRowBuffer
protected

◆ burstsPerStripe

const uint32_t gem5::memory::MemInterface::burstsPerStripe
protected

Definition at line 142 of file mem_interface.hh.

Referenced by decodePacket(), and gem5::memory::DRAMInterface::init().

◆ ctrl

MemCtrl* gem5::memory::MemInterface::ctrl
protected

◆ deviceRowBufferSize

const uint32_t gem5::memory::MemInterface::deviceRowBufferSize
protected

Definition at line 138 of file mem_interface.hh.

◆ deviceSize

const uint32_t gem5::memory::MemInterface::deviceSize
protected

Definition at line 137 of file mem_interface.hh.

Referenced by gem5::memory::DRAMInterface::DRAMInterface().

◆ devicesPerRank

const uint32_t gem5::memory::MemInterface::devicesPerRank
protected

Definition at line 139 of file mem_interface.hh.

Referenced by gem5::memory::DRAMInterface::DRAMInterface().

◆ maxCommandsPerWindow

unsigned int gem5::memory::MemInterface::maxCommandsPerWindow
protected

Number of commands that can issue in the defined controller command window, used to verify command bandwidth.

Definition at line 123 of file mem_interface.hh.

Referenced by gem5::memory::DRAMInterface::activateBank(), gem5::memory::NVMInterface::chooseRead(), gem5::memory::DRAMInterface::doBurstAccess(), gem5::memory::NVMInterface::doBurstAccess(), gem5::memory::DRAMInterface::prechargeBank(), and setCtrl().

◆ ranksPerChannel

const uint32_t gem5::memory::MemInterface::ranksPerChannel
protected

◆ readBufferSize

const uint32_t gem5::memory::MemInterface::readBufferSize

Buffer sizes for read and write queues in the controller These are passed to the controller on instantiation Defining them here allows for buffers to be resized based on memory type / configuration.

Definition at line 180 of file mem_interface.hh.

◆ rowBufferSize

const uint32_t gem5::memory::MemInterface::rowBufferSize
protected

◆ rowsPerBank

uint32_t gem5::memory::MemInterface::rowsPerBank
protected

Definition at line 145 of file mem_interface.hh.

Referenced by decodePacket(), and gem5::memory::DRAMInterface::DRAMInterface().

◆ tBURST

const Tick gem5::memory::MemInterface::tBURST
protected

◆ tCK

const GEM5_CLASS_VAR_USED Tick gem5::memory::MemInterface::tCK
protected

◆ tCS

const Tick gem5::memory::MemInterface::tCS
protected

◆ tRTW

const Tick gem5::memory::MemInterface::tRTW
protected

Definition at line 153 of file mem_interface.hh.

Referenced by minReadToWriteDataGap(), and readToWriteDelay().

◆ tWTR

const Tick gem5::memory::MemInterface::tWTR
protected

◆ writeBufferSize

const uint32_t gem5::memory::MemInterface::writeBufferSize

Definition at line 181 of file mem_interface.hh.


The documentation for this class was generated from the following files:

Generated on Tue Sep 21 2021 12:31:28 for gem5 by doxygen 1.8.17