gem5::PosixKvmTimer Class Reference

Timer based on standard POSIX timers. More...

#include <timer.hh>

Inheritance diagram for gem5::PosixKvmTimer:

Public Member Functions
	PosixKvmTimer (int signo, clockid_t clockID, float hostFactor, Tick hostFreq)
	~PosixKvmTimer ()
void	arm (Tick ticks) override
	Arm the timer so that it fires after a certain number of ticks.
void	disarm () override
	Disarm the timer.
bool	expired () override
Public Member Functions inherited from gem5::BaseKvmTimer
	BaseKvmTimer (int signo, float hostFactor, Tick hostFreq)
	Setup basic timer functionality shared by all timer implementations.
virtual	~BaseKvmTimer ()
Tick	resolution ()
	Determine the resolution of the timer in ticks.
Tick	ticksFromHostCycles (uint64_t cycles)
	Convert cycles executed on the host into Ticks executed in the simulator.
Tick	ticksFromHostNs (uint64_t ns)
	Convert nanoseconds executed on the host into Ticks executed in the simulator.

Protected Member Functions
Tick	calcResolution () override
	Calculate the timer resolution, used by resolution() which caches the result.
Protected Member Functions inherited from gem5::BaseKvmTimer
uint64_t	hostNs (Tick ticks)
	Convert a time in simulator ticks to host nanoseconds.
uint64_t	hostCycles (Tick ticks)
	Convert a time in simulator ticks to host cycles.

Private Attributes
clockid_t	clockID
timer_t	timer
struct itimerspec	prevTimerSpec

Additional Inherited Members
Protected Attributes inherited from gem5::BaseKvmTimer
int	signo
	Signal to deliver when the timer times out.

Detailed Description

Timer based on standard POSIX timers.

The POSIX timer API supports several different clock with different characteristics.

Note

It might be tempting to use CLOCK_(THREAD|PROCESS)_CPUTIME_ID, however, this clock usually has much lower resolution than the real-time clocks.

Definition at line 187 of file timer.hh.

Constructor & Destructor Documentation

PosixKvmTimer()

gem5::PosixKvmTimer::PosixKvmTimer	(	int	signo,
		clockid_t	clockID,
		float	hostFactor,
		Tick	hostFreq )

Parameters

signo	Signal to deliver
clockID	ID of the clock to use
hostFactor	Performance scaling factor
hostFreq	Clock frequency of the host

Definition at line 79 of file timer.cc.

References clockID, panic, gem5::sev, gem5::BaseKvmTimer::signo, gem5::sysGettid(), and timer.

~PosixKvmTimer()

gem5::PosixKvmTimer::~PosixKvmTimer

(

)

Definition at line 97 of file timer.cc.

References timer.

Member Function Documentation

arm()

void gem5::PosixKvmTimer::arm ( Tick ticks )

overridevirtual

Arm the timer so that it fires after a certain number of ticks.

Note

A timer implementation is free to convert between simulation ticks and virtualized time using any method it chooses. The accuracy of the timer therefore depends on what it measures, an accurate timer implementation should measure the number of cycles or instructions executed in the guest. If such counters are unavailable, it may fallback to wall clock time.

Parameters

ticks

Number of ticks until the timer fires

Implements gem5::BaseKvmTimer.

Definition at line 103 of file timer.cc.

References DPRINTF, gem5::BaseKvmTimer::hostNs(), panic, timer, and gem5::ArmISA::ts.

calcResolution()

Tick gem5::PosixKvmTimer::calcResolution ( )

overrideprotectedvirtual

Calculate the timer resolution, used by resolution() which caches the result.

Returns

Minimum number of ticks the timer can resolve

Implements gem5::BaseKvmTimer.

Definition at line 144 of file timer.cc.

References clockID, gem5::MIN_HOST_CYCLES, panic, gem5::BaseKvmTimer::resolution(), gem5::BaseKvmTimer::ticksFromHostCycles(), gem5::BaseKvmTimer::ticksFromHostNs(), and gem5::ArmISA::ts.

disarm()

void gem5::PosixKvmTimer::disarm ( )

overridevirtual

Disarm the timer.

When this method has returned, the timer may no longer deliver signals upon timeout.

Implements gem5::BaseKvmTimer.

Definition at line 123 of file timer.cc.

References DPRINTF, panic, prevTimerSpec, timer, and gem5::ArmISA::ts.

expired()

bool gem5::PosixKvmTimer::expired ( )

overridevirtual

Reimplemented from gem5::BaseKvmTimer.

Definition at line 137 of file timer.cc.

References prevTimerSpec.

Member Data Documentation

clockID

clockid_t gem5::PosixKvmTimer::clockID

private

Definition at line 208 of file timer.hh.

Referenced by calcResolution(), and PosixKvmTimer().

prevTimerSpec

struct itimerspec gem5::PosixKvmTimer::prevTimerSpec

private

Definition at line 210 of file timer.hh.

Referenced by disarm(), and expired().

timer

timer_t gem5::PosixKvmTimer::timer

private

Definition at line 209 of file timer.hh.

Referenced by arm(), disarm(), PosixKvmTimer(), and ~PosixKvmTimer().

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

• cpu/kvm/timer.hh
• cpu/kvm/timer.cc