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PosixKvmTimer Class Reference

Timer based on standard POSIX timers. More...

#include <timer.hh>

Inheritance diagram for PosixKvmTimer:
BaseKvmTimer

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 ( int  signo,
clockid_t  clockID,
float  hostFactor,
Tick  hostFreq 
)
Parameters
signoSignal to deliver
clockIDID of the clock to use
hostFactorPerformance scaling factor
hostFreqClock frequency of the host

Definition at line 78 of file timer.cc.

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

PosixKvmTimer::~PosixKvmTimer ( )

Definition at line 96 of file timer.cc.

References timer.

Member Function Documentation

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
ticksNumber of ticks until the timer fires

Implements BaseKvmTimer.

Definition at line 102 of file timer.cc.

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

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.

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_t PosixKvmTimer::clockID
private

Definition at line 203 of file timer.hh.

Referenced by calcResolution().

timer_t PosixKvmTimer::timer
private

Definition at line 204 of file timer.hh.

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


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

Generated on Fri Jun 9 2017 13:04:17 for gem5 by doxygen 1.8.6