Pool of FU's, specific to the new CPU model. More...

#include <fu_pool.hh>

Inheritance diagram for gem5::o3::FUPool:

Classes
class	FUIdxQueue
	Class that implements a circular queue to hold FU indices. More...

Public Types
typedef FUPoolParams	Params
Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params

Public Member Functions
	FUPool (const Params &p)
	Constructs a FU pool.
	~FUPool ()
int	getUnit (OpClass capability)
	Gets a FU providing the requested capability.
void	freeUnitNextCycle (int fu_idx)
	Frees a FU at the end of this cycle.
void	processFreeUnits ()
	Frees all FUs on the list.
int	size ()
	Returns the total number of FUs.
void	dump ()
	Debugging function used to dump FU information.
Cycles	getOpLatency (OpClass capability)
	Returns the operation execution latency of the given capability.
bool	isPipelined (OpClass capability)
	Returns the issue latency of the given capability.
bool	isDrained () const
	Have all the FUs drained?
void	takeOverFrom ()
	Takes over from another CPU's thread.
Public Member Functions inherited from gem5::SimObject
const Params &	params () 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.
virtual void	loadState (CheckpointIn &cp)
	loadState() is called on each SimObject when restoring from a checkpoint.
virtual void	initState ()
	initState() is called on each SimObject when not restoring from a checkpoint.
virtual void	regProbePoints ()
	Register probe points for this object.
virtual void	regProbeListeners ()
	Register probe listeners for this object.
ProbeManager *	getProbeManager ()
	Get the probe manager for this object.
virtual Port &	getPort (const std::string &if_name, PortID idx=InvalidPortID)
	Get a port with a given name and index.
virtual void	startup ()
	startup() is the final initialization call before simulation.
DrainState	drain () override
	Provide a default implementation of the drain interface for objects that don't need draining.
virtual void	memWriteback ()
	Write back dirty buffers to memory using functional writes.
virtual void	memInvalidate ()
	Invalidate the contents of memory buffers.
void	serialize (CheckpointOut &cp) const override
	Serialize an object.
void	unserialize (CheckpointIn &cp) override
	Unserialize an object.
Public Member Functions inherited from gem5::EventManager
EventQueue *	eventQueue () 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.
void	setCurTick (Tick newVal)
	EventManager (EventManager &em)
	Event manger manages events in the event queue.
	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.
void	serializeSection (CheckpointOut &cp, const std::string &name) const
void	unserializeSection (CheckpointIn &cp, const char *name)
	Unserialize an a child object.
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.
virtual void	notifyFork ()
	Notify a child process of a fork.
Public Member Functions inherited from gem5::statistics::Group
	Group (Group parent, const char name=nullptr)
	Construct a new statistics group.
virtual	~Group ()
virtual void	regStats ()
	Callback to set stat parameters.
virtual void	resetStats ()
	Callback to reset stats.
virtual void	preDumpStats ()
	Callback before stats are dumped.
void	addStat (statistics::Info *info)
	Register a stat with this group.
const std::map< std::string, Group * > &	getStatGroups () const
	Get all child groups associated with this object.
const std::vector< Info * > &	getStats () const
	Get all stats associated with this object.
void	addStatGroup (const char name, Group block)
	Add a stat block as a child of this block.
const Info *	resolveStat (std::string name) const
	Resolve a stat by its name within this group.
void	mergeStatGroup (Group *block)
	Merge the contents (stats & children) of a block to this block.
	Group ()=delete
	Group (const Group &)=delete
Group &	operator= (const Group &)=delete
Public Member Functions inherited from gem5::Named
	Named (std::string_view name_)
virtual	~Named ()=default
virtual std::string	name () const

Static Public Attributes
static constexpr auto	NoNeedFU = -3
	Named constants to differentiate cases where an instruction asked the FUPool for a free FU but did not get one.
static constexpr auto	NoCapableFU = -2
	Instruction asked for a FU but this FUPool does not have a FU for this instruction op type.
static constexpr auto	NoFreeFU = -1
	Instruction asked for a FU but all FU for this op type have already been allocated to other instructions this cycle.

Private Attributes
std::array< Cycles, Num_OpClasses >	maxOpLatencies
	Maximum op execution latencies, per op class.
std::array< bool, Num_OpClasses >	pipelined
	Whether op is pipelined or not.
std::bitset< Num_OpClasses >	capabilityList
	Bitvector listing capabilities of this FU pool.
std::vector< bool >	unitBusy
	Bitvector listing which FUs are busy.
std::vector< int >	unitsToBeFreed
	List of units to be freed at the end of this cycle.
FUIdxQueue	fuPerCapList [Num_OpClasses]
	Per op class queues of FUs that provide that capability.
int	numFU
	Number of FUs.
std::vector< FuncUnit * >	funcUnits
	Functional units.

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.
static SimObject *	find (const char *name)
	Find the SimObject with the given name and return a pointer to it.
static void	setSimObjectResolver (SimObjectResolver *resolver)
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.
static SimObjectResolver *	getSimObjectResolver ()
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.
Static Public Member Functions inherited from gem5::Serializable
static const std::string &	currentSection ()
	Gets the fully-qualified name of the active section.
static void	generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
	Generate a checkpoint file so that the serialization can be routed to it.
Protected Member Functions inherited from gem5::Drainable
	Drainable ()
virtual	~Drainable ()
virtual void	drainResume ()
	Resume execution after a successful drain.
void	signalDrainDone () const
	Signal that an object is drained.
Protected Attributes inherited from gem5::SimObject
const SimObjectParams &	_params
	Cached copy of the object parameters.
Protected Attributes inherited from gem5::EventManager
EventQueue *	eventq
	A pointer to this object's event queue.

Detailed Description

Pool of FU's, specific to the new CPU model.

The old FU pool had lists of free units and busy units, and whenever a FU was needed it would iterate through the free units to find a FU that provided the capability. This pool has lists of units specific to each of the capabilities, and whenever a FU is needed, it iterates through that list to find a free unit. The previous FU pool would have to be ticked each cycle to update which units became free. This FU pool lets the IEW stage handle freeing units, which frees them as their scheduled execution events complete. This limits units in this model to either have identical issue and op latencies, or 1 cycle issue latencies.

Definition at line 75 of file fu_pool.hh.

Member Typedef Documentation

◆ Params

typedef FUPoolParams gem5::o3::FUPool::Params

Definition at line 135 of file fu_pool.hh.

Constructor & Destructor Documentation

◆ FUPool()

gem5::o3::FUPool::FUPool ( const Params & p )

Constructs a FU pool.

Definition at line 85 of file fu_pool.cc.

References funcUnits, gem5::ArmISA::i, maxOpLatencies, numFU, gem5::MipsISA::p, pipelined, and gem5::SimObject::SimObject().

◆ ~FUPool()

gem5::o3::FUPool::~FUPool ( )

Definition at line 76 of file fu_pool.cc.

References gem5::PowerISA::fu, and funcUnits.

Member Function Documentation

◆ dump()

void gem5::o3::FUPool::dump ( )

Debugging function used to dump FU information.

Definition at line 205 of file fu_pool.cc.

References dump(), funcUnits, gem5::ArmISA::i, name(), numFU, and unitBusy.

Referenced by dump().

◆ freeUnitNextCycle()

void gem5::o3::FUPool::freeUnitNextCycle ( int fu_idx )

Frees a FU at the end of this cycle.

Definition at line 185 of file fu_pool.cc.

References freeUnitNextCycle(), unitBusy, and unitsToBeFreed.

Referenced by freeUnitNextCycle().

◆ getOpLatency()

Cycles gem5::o3::FUPool::getOpLatency ( OpClass capability )

inline

Returns the operation execution latency of the given capability.

Definition at line 190 of file fu_pool.hh.

References maxOpLatencies.

◆ getUnit()

int gem5::o3::FUPool::getUnit ( OpClass capability )

Gets a FU providing the requested capability.

Will mark the unit as busy, but leaves the freeing of the unit up to the IEW stage.

Parameters

capability The capability requested.

Returns: Returns NoCapableFU if the FU pool does not have the capability, NoFreeFU if there is no free FU, and the FU's index otherwise.

Definition at line 157 of file fu_pool.cc.

References capabilityList, fuPerCapList, getUnit(), NoCapableFU, NoFreeFU, numFU, and unitBusy.

Referenced by getUnit().

◆ isDrained()

bool gem5::o3::FUPool::isDrained ( ) const

Have all the FUs drained?

Definition at line 239 of file fu_pool.cc.

References gem5::ArmISA::i, isDrained(), numFU, and unitBusy.

Referenced by isDrained().

◆ isPipelined()

bool gem5::o3::FUPool::isPipelined ( OpClass capability )

inline

Returns the issue latency of the given capability.

Definition at line 195 of file fu_pool.hh.

References pipelined.

◆ processFreeUnits()

void gem5::o3::FUPool::processFreeUnits ( )

Frees all FUs on the list.

Definition at line 192 of file fu_pool.cc.

References processFreeUnits(), unitBusy, and unitsToBeFreed.

Referenced by processFreeUnits().

◆ size()

int gem5::o3::FUPool::size ( )

inline

Returns the total number of FUs.

Definition at line 184 of file fu_pool.hh.

References numFU.

◆ takeOverFrom()

void gem5::o3::FUPool::takeOverFrom ( )

inline

Takes over from another CPU's thread.

Definition at line 203 of file fu_pool.hh.

Member Data Documentation

◆ capabilityList

std::bitset<Num_OpClasses> gem5::o3::FUPool::capabilityList

private

Bitvector listing capabilities of this FU pool.

Definition at line 84 of file fu_pool.hh.

Referenced by getUnit().

◆ funcUnits

std::vector<FuncUnit *> gem5::o3::FUPool::funcUnits

private

Functional units.

Definition at line 132 of file fu_pool.hh.

Referenced by dump(), FUPool(), and ~FUPool().

◆ fuPerCapList

FUIdxQueue gem5::o3::FUPool::fuPerCapList[Num_OpClasses]

private

Per op class queues of FUs that provide that capability.

Definition at line 126 of file fu_pool.hh.

Referenced by getUnit().

◆ maxOpLatencies

std::array<Cycles, Num_OpClasses> gem5::o3::FUPool::maxOpLatencies

private

Maximum op execution latencies, per op class.

Definition at line 79 of file fu_pool.hh.

Referenced by FUPool(), and getOpLatency().

◆ NoCapableFU

auto gem5::o3::FUPool::NoCapableFU = -2

staticconstexpr

Instruction asked for a FU but this FUPool does not have a FU for this instruction op type.

Definition at line 156 of file fu_pool.hh.

Referenced by getUnit(), and gem5::o3::InstructionQueue::scheduleReadyInsts().

◆ NoFreeFU

auto gem5::o3::FUPool::NoFreeFU = -1

staticconstexpr

Instruction asked for a FU but all FU for this op type have already been allocated to other instructions this cycle.

Definition at line 163 of file fu_pool.hh.

Referenced by getUnit(), and gem5::o3::InstructionQueue::scheduleReadyInsts().

◆ NoNeedFU

auto gem5::o3::FUPool::NoNeedFU = -3

staticconstexpr

Named constants to differentiate cases where an instruction asked the FUPool for a free FU but did not get one.

Instruction asked for a FU but does not actually need any (e.g., NOP)

Definition at line 150 of file fu_pool.hh.

Referenced by gem5::o3::InstructionQueue::scheduleReadyInsts().

◆ numFU

int gem5::o3::FUPool::numFU

private

Number of FUs.

Definition at line 129 of file fu_pool.hh.

Referenced by dump(), FUPool(), getUnit(), isDrained(), and size().

◆ pipelined

std::array<bool, Num_OpClasses> gem5::o3::FUPool::pipelined

private

Whether op is pipelined or not.

Definition at line 81 of file fu_pool.hh.

Referenced by FUPool(), and isPipelined().

◆ unitBusy

std::vector<bool> gem5::o3::FUPool::unitBusy

private

Bitvector listing which FUs are busy.

Definition at line 87 of file fu_pool.hh.

Referenced by dump(), freeUnitNextCycle(), getUnit(), isDrained(), and processFreeUnits().

◆ unitsToBeFreed

std::vector<int> gem5::o3::FUPool::unitsToBeFreed

private

List of units to be freed at the end of this cycle.

Definition at line 90 of file fu_pool.hh.

Referenced by freeUnitNextCycle(), and processFreeUnits().

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

cpu/o3/fu_pool.hh
cpu/o3/fu_pool.cc

Classes

Public Types

Public Member Functions

Static Public Attributes

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Params

Constructor & Destructor Documentation

◆ FUPool()

◆ ~FUPool()

Member Function Documentation

◆ dump()

◆ freeUnitNextCycle()

◆ getOpLatency()

◆ getUnit()

◆ isDrained()

◆ isPipelined()

◆ processFreeUnits()

◆ size()

◆ takeOverFrom()

Member Data Documentation

◆ capabilityList

◆ funcUnits

◆ fuPerCapList

◆ maxOpLatencies

◆ NoCapableFU

◆ NoFreeFU

◆ NoNeedFU

◆ numFU

◆ pipelined

◆ unitBusy

◆ unitsToBeFreed