PosixKvmTimer Class Reference

Timer based on standard POSIX timers. More...

#include <timer.hh>

Inheritance diagram for PosixKvmTimer:

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

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

Private Attributes
clockid_t	clockID
timer_t	timer

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

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 183 of file timer.hh.

Constructor & Destructor Documentation

PosixKvmTimer()

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 78 of file timer.cc.

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

~PosixKvmTimer()

PosixKvmTimer::~PosixKvmTimer

(

)

Definition at line 96 of file timer.cc.

References timer.

Member Function Documentation

arm()

void PosixKvmTimer::arm ( Tick  ticks )

virtual

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 BaseKvmTimer.

Definition at line 102 of file timer.cc.

References DPRINTF, BaseKvmTimer::hostNs(), panic, timer, and ULL.

calcResolution()

Tick PosixKvmTimer::calcResolution ( )

protectedvirtual

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

Returns

Minimum number of ticks the timer can resolve

Implements BaseKvmTimer.

Definition at line 134 of file timer.cc.

References clockID, MIN_HOST_CYCLES, panic, BaseKvmTimer::resolution(), BaseKvmTimer::ticksFromHostCycles(), BaseKvmTimer::ticksFromHostNs(), and ULL.

disarm()

void PosixKvmTimer::disarm ( )

virtual

Disarm the timer.

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

Implements BaseKvmTimer.

Definition at line 122 of file timer.cc.

References DPRINTF, panic, and timer.

Member Data Documentation

clockID

clockid_t PosixKvmTimer::clockID

private

Definition at line 203 of file timer.hh.

Referenced by calcResolution().

timer

timer_t PosixKvmTimer::timer

private

Definition at line 204 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