The TaskScheduler keeps track of what tasks are currently schedulable. When a task is enqueued it is added to the run queue or the pending queue depending as to whether there is a runable or pending task ahead of it that violates the mutual exclusion policies. When tasks exit the scheduler re-examines the tasks on the pending queue which may now be runnable. It is important that this process is efficient such that exit events do not scan tasks that are not waiting on a particular task id or task instance to have a 0 count. More...

#include <task.h>

Collaboration diagram for TaskScheduler:

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Public Types
enum	CancelReturnCode { CANCELLED, FAILED, QUEUED }

typedef boost::function< void(const char file_name, uint32_t line_no, const Task task, const char *description, uint64_t delay)>	LogFn

Public Member Functions
	TaskScheduler (int thread_count=0)
	TaskScheduler constructor. TBB assumes it can use the "thread" invoking tbb::scheduler can be used for task scheduling. But, in our case we dont want "main" thread to be part of tbb. So, initialize TBB with one thread more than its default. More...

	~TaskScheduler ()
	Frees up the task_entry_db_ allocated for scheduler. More...

void	Enqueue (Task *task)
	Enqueues a task for running. Starts task if all policy rules are met else puts task in waitq. Enqueueing may may result in the task being immedietly added to the run queue or to a pending queue. Tasks may not be added to the run queue in violation of their exclusion policy. More...

void	EnqueueUnLocked (Task *task)

CancelReturnCode	Cancel (Task *task)
	Cancels a Task that can be in RUN/WAIT state. The caller needs to ensure that the task exists when Cancel() is invoked. More...

void	SetPolicy (int task_id, TaskPolicy &policy)
	Sets the task exclusion policy. Adds policy entries for the task Examples: More...

bool	GetRunStatus ()

int	GetTaskId (const std::string &name)

std::string	GetTaskName (int task_id) const

TaskStats *	GetTaskGroupStats (int task_id)

TaskStats *	GetTaskStats (int task_id)

TaskStats *	GetTaskStats (int task_id, int instance_id)

void	ClearTaskGroupStats (int task_id)

void	ClearTaskStats (int task_id)

void	ClearTaskStats (int task_id, int instance_id)

TaskGroup *	GetTaskGroup (int task_id)
	Get TaskGroup for a task_id. Grows task_entry_db_ if necessary. More...

TaskGroup *	QueryTaskGroup (int task_id)
	Query TaskGroup for a task_id.Assumes valid entry is present for task_id. More...

bool	IsTaskGroupEmpty (int task_id) const
	Check if there are any Tasks in the given TaskGroup. Assumes that all task ids are mutually exclusive with bgp::Config. More...

TaskEntry *	GetTaskEntry (int task_id, int instance_id)
	Get TaskGroup for a task_id. Grows task_entry_db_ if necessary. More...

TaskEntry *	QueryTaskEntry (int task_id, int instance_id)
	Query TaskEntry for a task-id and task-instance. More...

void	OnTaskExit (Task *task)
	Method invoked on exit of a Task. Exit of a task can potentially start tasks in pendingq. More...

void	Stop ()
	Stops scheduling of all tasks. More...

void	Start ()
	Starts scheduling of all tasks. More...

void	Print ()
	Debug print routine. More...

bool	IsEmpty (bool running_only=false)
	Returns true if there are no tasks running and/or enqueued If running_only is true, enqueued tasks are ignored i.e. return true if there are no running tasks. Ignore TaskGroup or TaskEntry if it is disabled. More...

void	Terminate ()

int	HardwareThreadCount ()

uint64_t	enqueue_count () const

uint64_t	done_count () const

uint64_t	cancel_count () const

void	SetMaxThreadCount (int n)
	Force number of threads. More...

void	GetSandeshData (SandeshTaskScheduler *resp, bool summary)

void	Log (const char file_name, uint32_t line_no, const Task task, const char *description, uint64_t delay)

void	RegisterLog (LogFn fn)

void	SetTrackRunTime (bool value)

bool	track_run_time () const

void	EnableLatencyThresholds (uint32_t execute, uint32_t schedule)
	Enable logging of tasks exceeding configured latency. More...

uint32_t	schedule_delay () const

uint32_t	execute_delay () const

bool	measure_delay () const

void	SetLatencyThreshold (const std::string &name, uint32_t execute, uint32_t schedule)

uint32_t	schedule_delay (Task *task) const

uint32_t	execute_delay (Task *task) const

void	set_event_manager (EventManager *evm)

void	DisableTaskGroup (int task_id)

void	EnableTaskGroup (int task_id)

void	DisableTaskEntry (int task_id, int instance_id)

void	EnableTaskEntry (int task_id, int instance_id)

void	ModifyTbbKeepAwakeTimeout (uint32_t timeout)

void	EnableMonitor (EventManager *evm, uint64_t tbb_keepawake_time_msec, uint64_t inactivity_time_msec, uint64_t poll_interval_msec)
	Enable Task monitoring. More...

const TaskMonitor *	task_monitor () const

const TaskTbbKeepAwake *	tbb_awake_task () const

bool	use_spawn () const

Static Public Member Functions
static void	Initialize (uint32_t thread_count=0, EventManager *evm=NULL)

static TaskScheduler *	GetInstance ()

static int	GetThreadCount (int thread_count=0)
	Get number of tbb worker threads. For testing purposes only. Limit the number of tbb worker threads. More...

static bool	ShouldUseSpawn ()

static int	GetDefaultThreadCount ()

static void	SetThreadAmpFactor (int n)
	following function allows one to increase max num of threads used by TBB More...

Private Types
typedef std::vector< TaskGroup * >	TaskGroupDb

typedef std::map< std::string, int >	TaskIdMap

Private Member Functions
void	SetRunningTask (Task *)
	This function should not be called in production code. It is only for unit testing to control current running task This function modifies the running task as specified by the input. More...

void	ClearRunningTask ()

void	WaitForTerminateCompletion ()

int	CountThreadsPerPid (pid_t pid)
	Platfrom-dependent subroutine in Linux and FreeBSD implementations, used only in TaskScheduler::WaitForTerminateCompletion(). In Linux, make sure that all the [tbb] threads launched have completely exited. We do so by looking for the Threads count of this process in /proc/<pid>/status. More...

	DISALLOW_COPY_AND_ASSIGN (TaskScheduler)

Private Attributes
bool	use_spawn_
	Use spawn() to run a tbb::task instead of enqueue() More...

TaskEntry *	stop_entry_

tbb::task_scheduler_init	task_scheduler_

tbb::mutex	mutex_

bool	running_

uint64_t	seqno_

TaskGroupDb	task_group_db_

tbb::reader_writer_lock	id_map_mutex_

TaskIdMap	id_map_

int	id_max_

LogFn	log_fn_

int	hw_thread_count_

bool	track_run_time_

bool	measure_delay_

uint32_t	schedule_delay_
	Log if time between enqueue and task-execute exceeds the delay. More...

uint32_t	execute_delay_
	Log if time taken to execute exceeds the delay. More...

uint64_t	enqueue_count_

uint64_t	done_count_

uint64_t	cancel_count_

EventManager *	evm_

TaskTbbKeepAwake *	tbb_awake_task_

TaskMonitor *	task_monitor_

Static Private Attributes
static const int	kVectorGrowSize = 16

static boost::scoped_ptr < TaskScheduler >	singleton_

static int	ThreadAmpFactor_ = 1
	following variable allows one to increase max num of threads used by TBB More...

Friends
class	ConcurrencyScope

Detailed Description

The TaskScheduler keeps track of what tasks are currently schedulable. When a task is enqueued it is added to the run queue or the pending queue depending as to whether there is a runable or pending task ahead of it that violates the mutual exclusion policies. When tasks exit the scheduler re-examines the tasks on the pending queue which may now be runnable. It is important that this process is efficient such that exit events do not scan tasks that are not waiting on a particular task id or task instance to have a 0 count.

Definition at line 178 of file task.h.

Member Typedef Documentation

typedef boost::function<void(const char *file_name, uint32_t line_no, const Task *task, const char *description, uint64_t delay)> TaskScheduler::LogFn

Definition at line 182 of file task.h.

typedef std::vector<TaskGroup *> TaskScheduler::TaskGroupDb

private

Definition at line 332 of file task.h.

typedef std::map<std::string, int> TaskScheduler::TaskIdMap

private

Definition at line 333 of file task.h.

Member Enumeration Documentation

enum TaskScheduler::CancelReturnCode

Enumerator
CANCELLED
FAILED
QUEUED

Definition at line 205 of file task.h.

Constructor & Destructor Documentation

TaskScheduler::TaskScheduler ( int thread_count = 0 )

TaskScheduler constructor. TBB assumes it can use the "thread" invoking tbb::scheduler can be used for task scheduling. But, in our case we dont want "main" thread to be part of tbb. So, initialize TBB with one thread more than its default.

Definition at line 444 of file task.cc.

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TaskScheduler::~TaskScheduler ( )

Frees up the task_entry_db_ allocated for scheduler.

Definition at line 455 of file task.cc.

Member Function Documentation

TaskScheduler::CancelReturnCode TaskScheduler::Cancel ( Task * task )

Cancels a Task that can be in RUN/WAIT state. The caller needs to ensure that the task exists when Cancel() is invoked.

Definition at line 699 of file task.cc.

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uint64_t TaskScheduler::cancel_count ( ) const

inline

Definition at line 287 of file task.h.

void TaskScheduler::ClearRunningTask ( )

private

Definition at line 1006 of file task.cc.

void TaskScheduler::ClearTaskGroupStats ( int task_id )

Definition at line 875 of file task.cc.

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void TaskScheduler::ClearTaskStats ( int task_id )

Definition at line 883 of file task.cc.

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void TaskScheduler::ClearTaskStats	(	int	task_id,
		int	instance_id
	)

Definition at line 891 of file task.cc.

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int TaskScheduler::CountThreadsPerPid ( pid_t pid )

private

Platfrom-dependent subroutine in Linux and FreeBSD implementations, used only in TaskScheduler::WaitForTerminateCompletion(). In Linux, make sure that all the [tbb] threads launched have completely exited. We do so by looking for the Threads count of this process in /proc/<pid>/status.

In FreeBSD use libprocstat to check how many threads is running in specific process.

Definition at line 923 of file task.cc.

void TaskScheduler::DisableTaskEntry	(	int	task_id,
		int	instance_id
	)

Definition at line 1032 of file task.cc.

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void TaskScheduler::DisableTaskGroup ( int task_id )

Definition at line 1015 of file task.cc.

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TaskScheduler::DISALLOW_COPY_AND_ASSIGN ( TaskScheduler )

private

uint64_t TaskScheduler::done_count ( ) const

inline

Definition at line 286 of file task.h.

void TaskScheduler::EnableLatencyThresholds	(	uint32_t	execute,
		uint32_t	schedule
	)

Enable logging of tasks exceeding configured latency.

Definition at line 595 of file task.cc.

void TaskScheduler::EnableMonitor	(	EventManager *	evm,
		uint64_t	tbb_keepawake_time_msec,
		uint64_t	inactivity_time_msec,
		uint64_t	poll_interval_msec
	)

Enable Task monitoring.

Definition at line 511 of file task.cc.

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void TaskScheduler::EnableTaskEntry	(	int	task_id,
		int	instance_id
	)

Definition at line 1037 of file task.cc.

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void TaskScheduler::EnableTaskGroup ( int task_id )

Definition at line 1025 of file task.cc.

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void TaskScheduler::Enqueue ( Task * task )

Enqueues a task for running. Starts task if all policy rules are met else puts task in waitq. Enqueueing may may result in the task being immedietly added to the run queue or to a pending queue. Tasks may not be added to the run queue in violation of their exclusion policy.

Definition at line 636 of file task.cc.

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uint64_t TaskScheduler::enqueue_count ( ) const

inline

Definition at line 285 of file task.h.

void TaskScheduler::EnqueueUnLocked ( Task * task )

Definition at line 642 of file task.cc.

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uint32_t TaskScheduler::execute_delay ( ) const

inline

Definition at line 302 of file task.h.

uint32_t TaskScheduler::execute_delay ( Task * task ) const

Definition at line 541 of file task.cc.

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int TaskScheduler::GetDefaultThreadCount ( )

static

Definition at line 429 of file task.cc.

TaskScheduler * TaskScheduler::GetInstance ( )

static

Definition at line 547 of file task.cc.

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bool TaskScheduler::GetRunStatus ( )

inline

Definition at line 227 of file task.h.

void TaskScheduler::GetSandeshData	(	SandeshTaskScheduler *	resp,
		bool	summary
	)

Definition at line 1622 of file task.cc.

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TaskEntry * TaskScheduler::GetTaskEntry	(	int	task_id,
		int	instance_id
	)

Get TaskGroup for a task_id. Grows task_entry_db_ if necessary.

Definition at line 583 of file task.cc.

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TaskGroup * TaskScheduler::GetTaskGroup ( int task_id )

Get TaskGroup for a task_id. Grows task_entry_db_ if necessary.

Definition at line 554 of file task.cc.

TaskStats * TaskScheduler::GetTaskGroupStats ( int task_id )

Definition at line 899 of file task.cc.

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int TaskScheduler::GetTaskId ( const std::string & name )

Definition at line 856 of file task.cc.

std::string TaskScheduler::GetTaskName ( int task_id ) const

Definition at line 846 of file task.cc.

TaskStats * TaskScheduler::GetTaskStats ( int task_id )

Definition at line 907 of file task.cc.

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TaskStats * TaskScheduler::GetTaskStats	(	int	task_id,
		int	instance_id
	)

Definition at line 915 of file task.cc.

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int TaskScheduler::GetThreadCount ( int thread_count = 0 )

static

Get number of tbb worker threads. For testing purposes only. Limit the number of tbb worker threads.

Definition at line 407 of file task.cc.

int TaskScheduler::HardwareThreadCount ( )

inline

Definition at line 276 of file task.h.

void TaskScheduler::Initialize	(	uint32_t	thread_count = `0`,
		EventManager *	evm = `NULL`
	)

static

Definition at line 478 of file task.cc.

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bool TaskScheduler::IsEmpty ( bool running_only = false )

Returns true if there are no tasks running and/or enqueued If running_only is true, enqueued tasks are ignored i.e. return true if there are no running tasks. Ignore TaskGroup or TaskEntry if it is disabled.

Definition at line 823 of file task.cc.

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bool TaskScheduler::IsTaskGroupEmpty ( int task_id ) const

Check if there are any Tasks in the given TaskGroup. Assumes that all task ids are mutually exclusive with bgp::Config.

Definition at line 574 of file task.cc.

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void TaskScheduler::Log	(	const char *	file_name,
		uint32_t	line_no,
		const Task *	task,
		const char *	description,
		uint64_t	delay
	)

Definition at line 523 of file task.cc.

bool TaskScheduler::measure_delay ( ) const

inline

Definition at line 304 of file task.h.

void TaskScheduler::ModifyTbbKeepAwakeTimeout ( uint32_t timeout )

Definition at line 505 of file task.cc.

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void TaskScheduler::OnTaskExit ( Task * task )

Method invoked on exit of a Task. Exit of a task can potentially start tasks in pendingq.

Definition at line 762 of file task.cc.

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void TaskScheduler::Print ( )

Debug print routine.

Definition at line 808 of file task.cc.

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TaskEntry * TaskScheduler::QueryTaskEntry	(	int	task_id,
		int	instance_id
	)

Query TaskEntry for a task-id and task-instance.

Definition at line 588 of file task.cc.

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TaskGroup * TaskScheduler::QueryTaskGroup ( int task_id )

Query TaskGroup for a task_id.Assumes valid entry is present for task_id.

Definition at line 570 of file task.cc.

void TaskScheduler::RegisterLog ( LogFn fn )

Definition at line 531 of file task.cc.

uint32_t TaskScheduler::schedule_delay ( ) const

inline

Definition at line 301 of file task.h.

uint32_t TaskScheduler::schedule_delay ( Task * task ) const

Definition at line 535 of file task.cc.

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void TaskScheduler::set_event_manager ( EventManager * evm )

Definition at line 493 of file task.cc.

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void TaskScheduler::SetLatencyThreshold	(	const std::string &	name,
		uint32_t	execute,
		uint32_t	schedule
	)

Definition at line 602 of file task.cc.

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void TaskScheduler::SetMaxThreadCount ( int n )

Force number of threads.

void TaskScheduler::SetPolicy	(	int	task_id,
		TaskPolicy &	policy
	)

Sets the task exclusion policy. Adds policy entries for the task Examples:

Policy <tid0> => <tid1, -1> <tid2, inst2> will result in following:
- task_db_[tid0] : Rule <tid1, -1> is added to policyq
- task_group_db_[tid0, inst2] : Rule <tid2, inst2> is added to policyq
The symmetry of policy will result in following additional rules,
- task_db_[tid1] : Rule <tid0, -1> is added to policyq
- task_group_db_[tid2, inst2] : Rule <tid0, inst2> is added to policyq

Definition at line 610 of file task.cc.

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void TaskScheduler::SetRunningTask ( Task * unit_test )

private

This function should not be called in production code. It is only for unit testing to control current running task This function modifies the running task as specified by the input.

Definition at line 1001 of file task.cc.

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void TaskScheduler::SetThreadAmpFactor ( int n )

static

following function allows one to increase max num of threads used by TBB

Definition at line 1011 of file task.cc.

void TaskScheduler::SetTrackRunTime ( bool value )

inline

Definition at line 296 of file task.h.

bool TaskScheduler::ShouldUseSpawn ( )

static

Definition at line 433 of file task.cc.

void TaskScheduler::Start ( )

Starts scheduling of all tasks.

Definition at line 798 of file task.cc.

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void TaskScheduler::Stop ( )

Stops scheduling of all tasks.

Definition at line 792 of file task.cc.

const TaskMonitor* TaskScheduler::task_monitor ( ) const

inline

Definition at line 322 of file task.h.

const TaskTbbKeepAwake* TaskScheduler::tbb_awake_task ( ) const

inline

Definition at line 323 of file task.h.

void TaskScheduler::Terminate ( )

Definition at line 978 of file task.cc.

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bool TaskScheduler::track_run_time ( ) const

inline

Definition at line 297 of file task.h.

bool TaskScheduler::use_spawn ( ) const

inline

Definition at line 324 of file task.h.

void TaskScheduler::WaitForTerminateCompletion ( )

private

Definition at line 952 of file task.cc.

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Friends And Related Function Documentation

friend class ConcurrencyScope

friend

Definition at line 331 of file task.h.

Member Data Documentation

uint64_t TaskScheduler::cancel_count_

private

Definition at line 389 of file task.h.

uint64_t TaskScheduler::done_count_

private

Definition at line 388 of file task.h.

uint64_t TaskScheduler::enqueue_count_

private

Definition at line 387 of file task.h.

EventManager* TaskScheduler::evm_

private

Definition at line 390 of file task.h.

uint32_t TaskScheduler::execute_delay_

private

Log if time taken to execute exceeds the delay.

Definition at line 385 of file task.h.

int TaskScheduler::hw_thread_count_

private

Definition at line 376 of file task.h.

TaskIdMap TaskScheduler::id_map_

private

Definition at line 372 of file task.h.

tbb::reader_writer_lock TaskScheduler::id_map_mutex_

private

Definition at line 371 of file task.h.

int TaskScheduler::id_max_

private

Definition at line 373 of file task.h.

const int TaskScheduler::kVectorGrowSize = 16

staticprivate

Definition at line 335 of file task.h.

LogFn TaskScheduler::log_fn_

private

Definition at line 375 of file task.h.

bool TaskScheduler::measure_delay_

private

Definition at line 379 of file task.h.

tbb::mutex TaskScheduler::mutex_

mutableprivate

Definition at line 366 of file task.h.

bool TaskScheduler::running_

private

Definition at line 367 of file task.h.

uint32_t TaskScheduler::schedule_delay_

private

Log if time between enqueue and task-execute exceeds the delay.

Definition at line 382 of file task.h.

uint64_t TaskScheduler::seqno_

private

Definition at line 368 of file task.h.

boost::scoped_ptr< TaskScheduler > TaskScheduler::singleton_

staticprivate

Definition at line 336 of file task.h.

TaskEntry* TaskScheduler::stop_entry_

private

Definition at line 363 of file task.h.

TaskGroupDb TaskScheduler::task_group_db_

private

Definition at line 369 of file task.h.

TaskMonitor* TaskScheduler::task_monitor_

private

Definition at line 397 of file task.h.

tbb::task_scheduler_init TaskScheduler::task_scheduler_

private

Definition at line 365 of file task.h.

TaskTbbKeepAwake* TaskScheduler::tbb_awake_task_

private

Definition at line 396 of file task.h.

int TaskScheduler::ThreadAmpFactor_ = 1

staticprivate

following variable allows one to increase max num of threads used by TBB

Definition at line 394 of file task.h.

bool TaskScheduler::track_run_time_

private

Definition at line 378 of file task.h.

bool TaskScheduler::use_spawn_

private

Use spawn() to run a tbb::task instead of enqueue()

Definition at line 362 of file task.h.

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

Public Types

Public Member Functions

Static Public Member Functions

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Friends

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation