An instance of a performance counter. More...

#include <perfevent.hh>

Public Member Functions
	PerfKvmCounter (PerfKvmCounterConfig &config, pid_t tid)
	Create and attach a new counter group.

	PerfKvmCounter (PerfKvmCounterConfig &config, pid_t tid, const PerfKvmCounter &parent)
	Create and attach a new counter and make it a member of an exist counter group.

	PerfKvmCounter ()
	Create a new counter, but don't attach it.

	~PerfKvmCounter ()

void	attach (PerfKvmCounterConfig &config, pid_t tid)
	Attach a counter.

void	attach (PerfKvmCounterConfig &config, pid_t tid, const PerfKvmCounter &parent)
	Attach a counter and make it a member of an existing counter group.

void	detach ()
	Detach a counter from PerfEvent.

bool	attached () const
	Check if a counter is attached.

void	start ()
	Start counting.

void	stop ()
	Stop counting.

void	period (uint64_t period)
	Update the period of an overflow counter.

void	refresh (int refresh)
	Enable a counter for a fixed number of events.

uint64_t	read () const
	Read the current value of a counter.

void	enableSignals (pid_t tid, int signal)
	Enable signal delivery to a thread on counter overflow.

void	enableSignals (int signal)
	Enable signal delivery on counter overflow.

Private Member Functions
	PerfKvmCounter (const PerfKvmCounter &that)

PerfKvmCounter &	operator= (const PerfKvmCounter &that)

void	attach (PerfKvmCounterConfig &config, pid_t tid, int group_fd)

pid_t	sysGettid ()
	Get the TID of the current thread.

void	mmapPerf (int pages)
	MMAP the PerfEvent file descriptor.

void	read (void *buf, size_t size) const
	Perform a read from the counter file descriptor.


int	fcntl (int cmd, long p1)
	PerfEvent fnctl interface.

int	fcntl (int cmd, void *p1)


int	ioctl (int request, long p1)
	PerfEvent ioctl interface.

int	ioctl (int request, void *p1)

int	ioctl (int request)

Private Attributes
int	fd
	PerfEvent file descriptor associated with counter.

struct perf_event_mmap_page *	ringBuffer
	Memory mapped PerfEvent sample ring buffer.

int	ringNumPages
	Total number of pages in ring buffer.

long	pageSize
	Cached host page size.

Detailed Description

An instance of a performance counter.

Definition at line 171 of file perfevent.hh.

Constructor & Destructor Documentation

◆ PerfKvmCounter() [1/4]

gem5::PerfKvmCounter::PerfKvmCounter	(	PerfKvmCounterConfig &	config,
		pid_t	tid )

Create and attach a new counter group.

Parameters

config	Counter configuration
tid	Thread to sample (0 indicates current thread)

Definition at line 71 of file perfevent.cc.

References attach().

◆ PerfKvmCounter() [2/4]

gem5::PerfKvmCounter::PerfKvmCounter	(	PerfKvmCounterConfig &	config,
		pid_t	tid,
		const PerfKvmCounter &	parent )

Create and attach a new counter and make it a member of an exist counter group.

Parameters

config	Counter configuration
tid	Thread to sample (0 indicates current thread)
parent	Group leader

Definition at line 77 of file perfevent.cc.

References attach().

◆ PerfKvmCounter() [3/4]

gem5::PerfKvmCounter::PerfKvmCounter ( )

Create a new counter, but don't attach it.

Definition at line 84 of file perfevent.cc.

◆ ~PerfKvmCounter()

gem5::PerfKvmCounter::~PerfKvmCounter ( )

Definition at line 89 of file perfevent.cc.

References attached(), and detach().

◆ PerfKvmCounter() [4/4]

gem5::PerfKvmCounter::PerfKvmCounter ( const PerfKvmCounter & that )

private

Member Function Documentation

◆ attach() [1/3]

void gem5::PerfKvmCounter::attach	(	PerfKvmCounterConfig &	config,
		pid_t	tid )

inline

Attach a counter.

Note: This operation is only supported if the counter isn't already attached.

Parameters

config	Counter configuration
tid	Thread to sample (0 indicates current thread)

Definition at line 207 of file perfevent.hh.

References attach().

Referenced by attach(), attach(), PerfKvmCounter(), and PerfKvmCounter().

◆ attach() [2/3]

void gem5::PerfKvmCounter::attach	(	PerfKvmCounterConfig &	config,
		pid_t	tid,
		const PerfKvmCounter &	parent )

inline

Attach a counter and make it a member of an existing counter group.

Note: This operation is only supported if the counter isn't already attached.

Parameters

config	Counter configuration
tid	Thread to sample (0 indicates current thread)
parent	Group leader

Definition at line 222 of file perfevent.hh.

References attach(), and fd.

◆ attach() [3/3]

void gem5::PerfKvmCounter::attach	(	PerfKvmCounterConfig &	config,
		pid_t	tid,
		int	group_fd )

private

Definition at line 162 of file perfevent.cc.

References attached(), gem5::PerfKvmCounterConfig::attr, fd, mmapPerf(), and panic.

◆ attached()

bool gem5::PerfKvmCounter::attached ( ) const

inline

Check if a counter is attached.

Definition at line 231 of file perfevent.hh.

References fd.

Referenced by attach(), detach(), fcntl(), ioctl(), mmapPerf(), read(), and ~PerfKvmCounter().

◆ detach()

void gem5::PerfKvmCounter::detach ( )

Detach a counter from PerfEvent.

Definition at line 96 of file perfevent.cc.

References attached(), fd, pageSize, ringBuffer, ringNumPages, and warn.

Referenced by ~PerfKvmCounter().

◆ enableSignals() [1/2]

void gem5::PerfKvmCounter::enableSignals ( int signal )

inline

Enable signal delivery on counter overflow.

Identical to enableSignals(pid_t) when called with the current TID as its parameter.

Parameters

signal Signal to send upon overflow

Definition at line 301 of file perfevent.hh.

References enableSignals(), and sysGettid().

Referenced by enableSignals().

◆ enableSignals() [2/2]

void gem5::PerfKvmCounter::enableSignals	(	pid_t	tid,
		int	signal )

Enable signal delivery to a thread on counter overflow.

Parameters

tid	Thread to deliver signal to
signal	Signal to send upon overflow

Definition at line 147 of file perfevent.cc.

References fcntl(), and panic.

Referenced by gem5::PerfKvmTimer::PerfKvmTimer().

◆ fcntl() [1/2]

int gem5::PerfKvmCounter::fcntl	(	int	cmd,
		long	p1 )

private

PerfEvent fnctl interface.

Parameters

cmd	fcntl command
p1	Request parameter

Returns: -1 on error (error number in errno), ioctl dependent value otherwise.

Definition at line 227 of file perfevent.cc.

References attached(), and fd.

Referenced by enableSignals().

◆ fcntl() [2/2]

int gem5::PerfKvmCounter::fcntl	(	int	cmd,
		void *	p1 )

inlineprivate

Definition at line 343 of file perfevent.hh.

References fcntl().

Referenced by fcntl().

◆ ioctl() [1/3]

int gem5::PerfKvmCounter::ioctl ( int request )

inlineprivate

Definition at line 358 of file perfevent.hh.

References ioctl(), and gem5::X86ISA::L.

Referenced by ioctl().

◆ ioctl() [2/3]

int gem5::PerfKvmCounter::ioctl	(	int	request,
		long	p1 )

private

PerfEvent ioctl interface.

Parameters

request	PerfEvent request
p1	Optional request parameter

Returns: -1 on error (error number in errno), ioctl dependent value otherwise.

Definition at line 234 of file perfevent.cc.

References attached(), and fd.

Referenced by period(), refresh(), start(), and stop().

◆ ioctl() [3/3]

int gem5::PerfKvmCounter::ioctl	(	int	request,
		void *	p1 )

inlineprivate

Definition at line 357 of file perfevent.hh.

References ioctl().

Referenced by ioctl().

◆ mmapPerf()

void gem5::PerfKvmCounter::mmapPerf ( int pages )

private

MMAP the PerfEvent file descriptor.

Note: We currently don't use the ring buffer, but PerfEvent requires this to be mapped for overflow handling to work.; Overflow handling requires at least one buf_page to be mapped.

Parameters

pages number of pages in circular sample buffer. Must be an even power of 2.

Definition at line 204 of file perfevent.cc.

References attached(), fd, pageSize, panic, ringBuffer, and ringNumPages.

Referenced by attach().

◆ operator=()

PerfKvmCounter & gem5::PerfKvmCounter::operator= ( const PerfKvmCounter & that )

private

◆ period()

void gem5::PerfKvmCounter::period ( uint64_t period )

Update the period of an overflow counter.

Warning: This ioctl has some pretty bizarre semantics. It seems like the new period isn't effective until after the next counter overflow. If you use this method to change the sample period, you will see one sample with the old period and then start sampling with the new period. This problem was fixed for ARM in version 3.7 of the kernel.; This method doesn't work at all on some 2.6.3x kernels since it has inverted check for the return value when copying parameters from userspace.

Parameters

period Overflow period in events

Definition at line 124 of file perfevent.cc.

References ioctl(), panic, and period().

Referenced by gem5::PerfKvmTimer::arm(), and period().

◆ read() [1/2]

uint64_t gem5::PerfKvmCounter::read ( ) const

Read the current value of a counter.

Definition at line 138 of file perfevent.cc.

References read().

Referenced by read(), and read().

◆ read() [2/2]

void gem5::PerfKvmCounter::read	(	void *	buf,
		size_t	size ) const

private

Perform a read from the counter file descriptor.

Parameters

buf	Destination buffer
size	Amount of data to read

Definition at line 241 of file perfevent.cc.

References attached(), fd, panic, and read().

◆ refresh()

void gem5::PerfKvmCounter::refresh ( int refresh )

Enable a counter for a fixed number of events.

When this method is called, perf event enables the counter if it was disabled. It then leaves the counter enabled until it has overflowed a refresh times.

Note: This does not update the period of the counter.

Parameters

refresh Number of overflows before disabling the counter.

Definition at line 131 of file perfevent.cc.

References ioctl(), panic, and refresh().

Referenced by gem5::PerfKvmTimer::arm(), and refresh().

◆ start()

void gem5::PerfKvmCounter::start ( )

Start counting.

Note: If this counter is a group leader, it will start the entire group.

Definition at line 110 of file perfevent.cc.

References ioctl(), and panic.

◆ stop()

void gem5::PerfKvmCounter::stop ( )

Stop counting.

Note: If this counter is a group leader, it will stop the entire group.

Definition at line 117 of file perfevent.cc.

References ioctl(), and panic.

Referenced by gem5::PerfKvmTimer::disarm().

◆ sysGettid()

pid_t gem5::PerfKvmCounter::sysGettid ( )

private

Get the TID of the current thread.

Returns: Current thread's TID

Definition at line 198 of file perfevent.cc.

Referenced by enableSignals().

Member Data Documentation

◆ fd

int gem5::PerfKvmCounter::fd

private

PerfEvent file descriptor associated with counter.

-1 if not attached to PerfEvent.

Definition at line 373 of file perfevent.hh.

Referenced by attach(), attach(), attached(), detach(), fcntl(), ioctl(), mmapPerf(), and read().

◆ pageSize

long gem5::PerfKvmCounter::pageSize

private

Cached host page size.

Definition at line 381 of file perfevent.hh.

Referenced by detach(), and mmapPerf().

◆ ringBuffer

struct perf_event_mmap_page* gem5::PerfKvmCounter::ringBuffer

private

Memory mapped PerfEvent sample ring buffer.

Definition at line 376 of file perfevent.hh.

Referenced by detach(), and mmapPerf().

◆ ringNumPages

int gem5::PerfKvmCounter::ringNumPages

private

Total number of pages in ring buffer.

Definition at line 378 of file perfevent.hh.

Referenced by detach(), and mmapPerf().

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

cpu/kvm/perfevent.hh
cpu/kvm/perfevent.cc

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ PerfKvmCounter() [1/4]

◆ PerfKvmCounter() [2/4]

◆ PerfKvmCounter() [3/4]

◆ ~PerfKvmCounter()

◆ PerfKvmCounter() [4/4]

Member Function Documentation

◆ attach() [1/3]

◆ attach() [2/3]

◆ attach() [3/3]

◆ attached()

◆ detach()

◆ enableSignals() [1/2]

◆ enableSignals() [2/2]

◆ fcntl() [1/2]

◆ fcntl() [2/2]

◆ ioctl() [1/3]

◆ ioctl() [2/3]

◆ ioctl() [3/3]

◆ mmapPerf()

◆ operator=()

◆ period()

◆ read() [1/2]

◆ read() [2/2]

◆ refresh()

◆ start()

◆ stop()

◆ sysGettid()

Member Data Documentation

◆ fd

◆ pageSize

◆ ringBuffer

◆ ringNumPages