gem5  v20.1.0.0
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MemInterface Class Referenceabstract

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

#include <mem_interface.hh>

Inheritance diagram for MemInterface:
AbstractMemory ClockedObject SimObject Clocked EventManager Serializable Drainable Stats::Group DRAMInterface NVMInterface

Classes

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

Public Types

typedef MemInterfaceParams Params
 
- Public Types inherited from AbstractMemory
typedef AbstractMemoryParams Params
 
- Public Types inherited from ClockedObject
typedef ClockedObjectParams Params
 Parameters of ClockedObject. More...
 
- Public Types inherited from 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 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...
 
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...
 
const Paramsparams () const
 
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 ClockedObject
 ClockedObject (const ClockedObjectParams *p)
 
const Paramsparams () const
 
void serialize (CheckpointOut &cp) const override
 Serialize an object. More...
 
void unserialize (CheckpointIn &cp) override
 Unserialize an object. More...
 
- Public Member Functions inherited from SimObject
const Paramsparams () const
 
 SimObject (const Params *_params)
 
virtual ~SimObject ()
 
virtual const std::string name () const
 
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 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 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 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 Stats::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 (Stats::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...
 
 Group ()=delete
 
 Group (const Group &)=delete
 
Groupoperator= (const Group &)=delete
 
- Public Member Functions inherited from 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 ClockedObject
PowerStatepowerState
 

Protected Member Functions

virtual Tick writeToReadDelay () const
 
Tick readToWriteDelay () const
 
Tick rankToRankDelay () const
 
- Protected Member Functions inherited from AbstractMemory
bool checkLockedAddrList (PacketPtr pkt)
 
void trackLoadLocked (PacketPtr pkt)
 
bool writeOK (PacketPtr pkt)
 
- Protected Member Functions inherited from 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 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 Tick M5_CLASS_VAR_USED tCK
 General timing requirements. More...
 
const Tick tCS
 
const Tick tBURST
 
const Tick tRTW
 
const Tick tWTR
 
- Protected Attributes inherited from 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...
 
AbstractMemory::MemStats stats
 
- Protected Attributes inherited from SimObject
const SimObjectParams * _params
 Cached copy of the object parameters. More...
 
- Protected Attributes inherited from EventManager
EventQueueeventq
 A pointer to this object's event queue. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from SimObject
static void serializeAll (CheckpointOut &cp)
 Serialize 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 Public Member Functions inherited from Serializable
static const std::string & currentSection ()
 Gets the fully-qualified name of the active section. More...
 
static void serializeAll (const std::string &cpt_dir)
 Serializes all the SimObjects. More...
 
static void unserializeGlobals (CheckpointIn &cp)
 

Detailed Description

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

Definition at line 70 of file mem_interface.hh.

Member Typedef Documentation

◆ Params

typedef MemInterfaceParams MemInterface::Params

Definition at line 291 of file mem_interface.hh.

Constructor & Destructor Documentation

◆ MemInterface()

MemInterface::MemInterface ( const Params _p)

Definition at line 54 of file mem_interface.cc.

Member Function Documentation

◆ accessLatency()

virtual Tick MemInterface::accessLatency ( ) const
pure virtual

Implemented in NVMInterface, and DRAMInterface.

◆ addRankToRankDelay()

virtual void 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 NVMInterface, and DRAMInterface.

◆ allRanksDrained()

virtual bool MemInterface::allRanksDrained ( ) const
pure virtual

Check drain state of interface.

Returns
true if all ranks are drained and idle

Implemented in NVMInterface, and DRAMInterface.

◆ burstReady()

virtual bool 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 NVMInterface, and DRAMInterface.

◆ bytesPerBurst()

uint32_t MemInterface::bytesPerBurst ( ) const
inline
Returns
number of bytes in a burst for this interface

Definition at line 233 of file mem_interface.hh.

References burstSize.

Referenced by MemCtrl::addToReadQueue(), MemCtrl::addToWriteQueue(), MemCtrl::burstAlign(), MemCtrl::processNextReqEvent(), and MemCtrl::recvTimingReq().

◆ chooseNextFRFCFS()

virtual std::pair<MemPacketQueue::iterator, Tick> 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 NVMInterface, and DRAMInterface.

◆ commandOffset()

virtual Tick MemInterface::commandOffset ( ) const
pure virtual

Implemented in NVMInterface, and DRAMInterface.

◆ decodePacket()

MemPacket * 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 83 of file mem_interface.cc.

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

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

◆ getCtrlAddr()

Addr 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 193 of file mem_interface.hh.

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

Referenced by decodePacket().

◆ minReadToWriteDataGap()

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

Definition at line 258 of file mem_interface.hh.

References tCS, and tRTW.

Referenced by MemCtrl::minReadToWriteDataGap().

◆ minWriteToReadDataGap()

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

Definition at line 264 of file mem_interface.hh.

References tCS, and tWTR.

Referenced by MemCtrl::minWriteToReadDataGap().

◆ rankDelay()

Tick MemInterface::rankDelay ( ) const
inline

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

Returns
required rank to rank delay

Definition at line 252 of file mem_interface.hh.

References tCS.

◆ rankToRankDelay()

Tick MemInterface::rankToRankDelay ( ) const
inlineprotected

◆ readToWriteDelay()

Tick MemInterface::readToWriteDelay ( ) const
inlineprotected

Definition at line 157 of file mem_interface.hh.

References tBURST, and tRTW.

Referenced by DRAMInterface::doBurstAccess(), and NVMInterface::doBurstAccess().

◆ setCtrl()

void 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 76 of file mem_interface.cc.

References ctrl, maxCommandsPerWindow, and tCK.

◆ setupRank()

virtual void 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 NVMInterface, and DRAMInterface.

◆ writeToReadDelay()

virtual Tick MemInterface::writeToReadDelay ( ) const
inlineprotectedvirtual

Reimplemented in DRAMInterface.

Definition at line 152 of file mem_interface.hh.

References tBURST, and tWTR.

Referenced by NVMInterface::doBurstAccess().

Member Data Documentation

◆ addrMapping

Enums::AddrMap MemInterface::addrMapping
protected

Memory controller configuration initialized based on parameter values.

Definition at line 122 of file mem_interface.hh.

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

◆ banksPerRank

const uint32_t MemInterface::banksPerRank
protected

◆ burstSize

const uint32_t 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 129 of file mem_interface.hh.

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

◆ burstsPerRowBuffer

const uint32_t MemInterface::burstsPerRowBuffer
protected

◆ burstsPerStripe

const uint32_t MemInterface::burstsPerStripe
protected

Definition at line 135 of file mem_interface.hh.

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

◆ ctrl

MemCtrl* MemInterface::ctrl
protected

◆ deviceRowBufferSize

const uint32_t MemInterface::deviceRowBufferSize
protected

Definition at line 131 of file mem_interface.hh.

◆ deviceSize

const uint32_t MemInterface::deviceSize
protected

Definition at line 130 of file mem_interface.hh.

Referenced by DRAMInterface::DRAMInterface().

◆ devicesPerRank

const uint32_t MemInterface::devicesPerRank
protected

Definition at line 132 of file mem_interface.hh.

Referenced by DRAMInterface::DRAMInterface().

◆ maxCommandsPerWindow

unsigned int MemInterface::maxCommandsPerWindow
protected

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

Definition at line 116 of file mem_interface.hh.

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

◆ ranksPerChannel

const uint32_t MemInterface::ranksPerChannel
protected

◆ readBufferSize

const uint32_t 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 173 of file mem_interface.hh.

◆ rowBufferSize

const uint32_t MemInterface::rowBufferSize
protected

Definition at line 133 of file mem_interface.hh.

Referenced by DRAMInterface::DRAMInterface(), and DRAMInterface::init().

◆ rowsPerBank

uint32_t MemInterface::rowsPerBank
protected

Definition at line 138 of file mem_interface.hh.

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

◆ tBURST

const Tick MemInterface::tBURST
protected

◆ tCK

const Tick M5_CLASS_VAR_USED MemInterface::tCK
protected

◆ tCS

const Tick MemInterface::tCS
protected

◆ tRTW

const Tick MemInterface::tRTW
protected

Definition at line 146 of file mem_interface.hh.

Referenced by minReadToWriteDataGap(), and readToWriteDelay().

◆ tWTR

const Tick MemInterface::tWTR
protected

◆ writeBufferSize

const uint32_t MemInterface::writeBufferSize

Definition at line 174 of file mem_interface.hh.


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

Generated on Wed Sep 30 2020 14:02:27 for gem5 by doxygen 1.8.17