Class EpollEventLoop

java.lang.Object

java.util.concurrent.AbstractExecutorService

io.netty.util.concurrent.AbstractEventExecutor

io.netty.util.concurrent.AbstractScheduledEventExecutor

io.netty.util.concurrent.SingleThreadEventExecutor

io.netty.channel.SingleThreadEventLoop

io.netty.channel.epoll.EpollEventLoop

All Implemented Interfaces:

EventLoop, EventLoopGroup, EventExecutor, EventExecutorGroup, OrderedEventExecutor, Iterable<EventExecutor>, Executor, ExecutorService, ScheduledExecutorService

public class EpollEventLoop
extends SingleThreadEventLoop

EventLoop which uses epoll under the covers. Only works on Linux!

Nested Class Summary

Nested classes/interfaces inherited from class SingleThreadEventLoop

SingleThreadEventLoop.ChannelsReadOnlyIterator<T>

Modifier and Type	Class	Description
protected static final class	SingleThreadEventLoop.ChannelsReadOnlyIterator<T extends Channel>

Nested classes/interfaces inherited from class SingleThreadEventExecutor

SingleThreadEventExecutor.NonWakeupRunnable

Modifier and Type	Class	Description
protected static interface	SingleThreadEventExecutor.NonWakeupRunnable	Deprecated. override SingleThreadEventExecutor.wakesUpForTask(Runnable) to re-create this behaviour

Nested classes/interfaces inherited from class AbstractEventExecutor

AbstractEventExecutor.LazyRunnable

Modifier and Type	Class	Description
static interface	AbstractEventExecutor.LazyRunnable	Deprecated. override SingleThreadEventExecutor.wakesUpForTask(Runnable) to re-create this behaviour

Field Summary

Fields inherited from class SingleThreadEventLoop

DEFAULT_MAX_PENDING_TASKS

Modifier and Type	Field	Description
protected static final int	DEFAULT_MAX_PENDING_TASKS

Method Summary

Modifier and Type	Method	Description
protected boolean	afterScheduledTaskSubmitted(long deadlineNanos)	See AbstractScheduledEventExecutor.beforeScheduledTaskSubmitted(long).
protected boolean	beforeScheduledTaskSubmitted(long deadlineNanos)	Called from arbitrary non-EventExecutor threads prior to scheduled task submission.
protected void	cleanup()	Do nothing, sub-classes may override
void	closeFileDescriptors()	This method is intended for use by process checkpoint/restore integration, such as OpenJDK CRaC.
int	getIoRatio()	Returns the percentage of the desired amount of time spent for I/O in the event loop.
protected Queue<Runnable>	newTaskQueue(int maxPendingTasks)	Create a new Queue which will holds the tasks to execute.
void	openFileDescriptors()	This method is intended for use by a process checkpoint/restore integration, such as OpenJDK CRaC.
int	registeredChannels()	Returns the number of Channels registered with this EventLoop or -1 if operation is not supported.
Iterator<Channel>	registeredChannelsIterator()
protected void	run()	Runs the task-processing loop until SingleThreadEventExecutor.confirmShutdown() returns true.
void	setIoRatio(int ioRatio)	Sets the percentage of the desired amount of time spent for I/O in the event loop.
protected void	wakeup(boolean inEventLoop)

Methods inherited from class SingleThreadEventLoop

afterRunningAllTasks, executeAfterEventLoopIteration, hasTasks, next, parent, pendingTasks, register, register, register

Modifier and Type	Method	Description
protected void	afterRunningAllTasks()	Invoked before returning from SingleThreadEventExecutor.runAllTasks() and SingleThreadEventExecutor.runAllTasks(long).
final void	executeAfterEventLoopIteration(Runnable task)	Adds a task to be run once at the end of next (or current) eventloop iteration.
protected boolean	hasTasks()
EventLoop	next()	Returns a reference to itself.
EventLoopGroup	parent()	Return the EventExecutorGroup which is the parent of this EventExecutor,
int	pendingTasks()	Return the number of tasks that are pending for processing.
ChannelFuture	register(Channel channel)	Register a Channel with this EventLoop.
ChannelFuture	register(ChannelPromise promise)	Register a Channel with this EventLoop using a ChannelFuture.
ChannelFuture	register(Channel channel, ChannelPromise promise)	Deprecated.

Methods inherited from class SingleThreadEventExecutor

addShutdownHook, addTask, awaitTermination, confirmShutdown, deadlineNanos, delayNanos, execute, inEventLoop, interruptThread, invokeAll, invokeAll, invokeAny, invokeAny, isShutdown, isShuttingDown, isTerminated, lazyExecute, newTaskQueue, peekTask, pollTask, pollTaskFrom, reject, reject, removeShutdownHook, removeTask, runAllTasks, runAllTasks, runAllTasksFrom, runScheduledAndExecutorTasks, shutdown, shutdownGracefully, takeTask, terminationFuture, threadProperties, updateLastExecutionTime, wakesUpForTask

Modifier and Type	Method	Description
void	addShutdownHook(Runnable task)	Add a Runnable which will be executed on shutdown of this instance
protected void	addTask(Runnable task)	Add a task to the task queue, or throws a RejectedExecutionException if this instance was shutdown before.
boolean	awaitTermination(long timeout, TimeUnit unit)
protected boolean	confirmShutdown()	Confirm that the shutdown if the instance should be done now!
protected long	deadlineNanos()	Returns the absolute point in time (relative to AbstractScheduledEventExecutor.getCurrentTimeNanos()) at which the next closest scheduled task should run.
protected long	delayNanos(long currentTimeNanos)	Returns the amount of time left until the scheduled task with the closest dead line is executed.
void	execute(Runnable task)
boolean	inEventLoop(Thread thread)	Return true if the given Thread is executed in the event loop, false otherwise.
protected void	interruptThread()	Interrupt the current running Thread.
<T> List<Future<T>>	invokeAll(Collection<? extends Callable<T>> tasks)
<T> List<Future<T>>	invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
<T> T	invokeAny(Collection<? extends Callable<T>> tasks)
<T> T	invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
boolean	isShutdown()
boolean	isShuttingDown()	Returns true if and only if all EventExecutors managed by this EventExecutorGroup are being shut down gracefully or was shut down.
boolean	isTerminated()
void	lazyExecute(Runnable task)	Like Executor.execute(Runnable) but does not guarantee the task will be run until either a non-lazy task is executed or the executor is shut down.
protected Queue<Runnable>	newTaskQueue()	Deprecated. Please use and override SingleThreadEventExecutor.newTaskQueue(int).
protected Runnable	peekTask()
protected Runnable	pollTask()
protected static Runnable	pollTaskFrom(Queue<Runnable> taskQueue)
protected static void	reject()
protected final void	reject(Runnable task)	Offers the task to the associated RejectedExecutionHandler.
void	removeShutdownHook(Runnable task)	Remove a previous added Runnable as a shutdown hook
protected boolean	removeTask(Runnable task)
protected boolean	runAllTasks()	Poll all tasks from the task queue and run them via Runnable.run() method.
protected boolean	runAllTasks(long timeoutNanos)	Poll all tasks from the task queue and run them via Runnable.run() method.
protected final boolean	runAllTasksFrom(Queue<Runnable> taskQueue)	Runs all tasks from the passed taskQueue.
protected final boolean	runScheduledAndExecutorTasks(int maxDrainAttempts)	Execute all expired scheduled tasks and all current tasks in the executor queue until both queues are empty, or maxDrainAttempts has been exceeded.
void	shutdown()	Deprecated.
Future<?>	shutdownGracefully(long quietPeriod, long timeout, TimeUnit unit)	Signals this executor that the caller wants the executor to be shut down.
protected Runnable	takeTask()	Take the next Runnable from the task queue and so will block if no task is currently present.
Future<?>	terminationFuture()	Returns the Future which is notified when all EventExecutors managed by this EventExecutorGroup have been terminated.
final ThreadProperties	threadProperties()	Returns the ThreadProperties of the Thread that powers the SingleThreadEventExecutor.
protected void	updateLastExecutionTime()	Updates the internal timestamp that tells when a submitted task was executed most recently.
protected boolean	wakesUpForTask(Runnable task)	Can be overridden to control which tasks require waking the EventExecutor thread if it is waiting so that they can be run immediately.

Methods inherited from class AbstractScheduledEventExecutor

cancelScheduledTasks, deadlineToDelayNanos, getCurrentTimeNanos, hasScheduledTasks, initialNanoTime, nanoTime, nextScheduledTaskDeadlineNanos, nextScheduledTaskNano, pollScheduledTask, pollScheduledTask, schedule, schedule, scheduleAtFixedRate, scheduleWithFixedDelay, validateScheduled

Modifier and Type	Method	Description
protected void	cancelScheduledTasks()	Cancel all scheduled tasks.
protected static long	deadlineToDelayNanos(long deadlineNanos)	Given an arbitrary deadline deadlineNanos, calculate the number of nano seconds from now deadlineNanos would expire.
protected long	getCurrentTimeNanos()	Get the current time in nanoseconds by this executor's clock.
protected final boolean	hasScheduledTasks()	Returns true if a scheduled task is ready for processing.
protected static long	initialNanoTime()	The initial value used for delay and computations based upon a monatomic time source.
protected static long	nanoTime()	Deprecated. Use the non-static AbstractScheduledEventExecutor.getCurrentTimeNanos() instead.
protected final long	nextScheduledTaskDeadlineNanos()	Return the deadline (in nanoseconds) when the next scheduled task is ready to be run or -1 if no task is scheduled.
protected final long	nextScheduledTaskNano()	Return the nanoseconds until the next scheduled task is ready to be run or -1 if no task is scheduled.
protected final Runnable	pollScheduledTask()
protected final Runnable	pollScheduledTask(long nanoTime)	Return the Runnable which is ready to be executed with the given nanoTime.
ScheduledFuture<?>	schedule(Runnable command, long delay, TimeUnit unit)
<V> ScheduledFuture<V>	schedule(Callable<V> callable, long delay, TimeUnit unit)
ScheduledFuture<?>	scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit)
ScheduledFuture<?>	scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit)
protected void	validateScheduled(long amount, TimeUnit unit)	Deprecated. will be removed in the future.

Methods inherited from class AbstractEventExecutor

inEventLoop, iterator, newFailedFuture, newProgressivePromise, newPromise, newSucceededFuture, newTaskFor, newTaskFor, runTask, safeExecute, shutdownGracefully, shutdownNow, submit, submit, submit

Modifier and Type	Method	Description
boolean	inEventLoop()	Calls EventExecutor.inEventLoop(Thread) with Thread.currentThread() as argument
Iterator<EventExecutor>	iterator()
<V> Future<V>	newFailedFuture(Throwable cause)	Create a new Future which is marked as failed already.
<V> ProgressivePromise<V>	newProgressivePromise()	Create a new ProgressivePromise.
<V> Promise<V>	newPromise()	Return a new Promise.
<V> Future<V>	newSucceededFuture(V result)	Create a new Future which is marked as succeeded already.
protected final <T> RunnableFuture<T>	newTaskFor(Runnable runnable, T value)
protected final <T> RunnableFuture<T>	newTaskFor(Callable<T> callable)
protected static void	runTask(Runnable task)
protected static void	safeExecute(Runnable task)	Try to execute the given Runnable and just log if it throws a Throwable.
Future<?>	shutdownGracefully()	Shortcut method for EventExecutorGroup.shutdownGracefully(long, long, TimeUnit) with sensible default values.
List<Runnable>	shutdownNow()	Deprecated. EventExecutorGroup.shutdownGracefully(long, long, TimeUnit) or AbstractEventExecutor.shutdownGracefully() instead.
Future<?>	submit(Runnable task)
<T> Future<T>	submit(Runnable task, T result)
<T> Future<T>	submit(Callable<T> task)

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Iterable

forEach, spliterator

Method Details

openFileDescriptors

@UnstableApi
public void openFileDescriptors()

This method is intended for use by a process checkpoint/restore integration, such as OpenJDK CRaC.

wakeup

protected void wakeup(boolean inEventLoop)

Overrides:

wakeup in class SingleThreadEventExecutor

beforeScheduledTaskSubmitted

protected boolean beforeScheduledTaskSubmitted(long deadlineNanos)

Description copied from class: AbstractScheduledEventExecutor

Called from arbitrary non-EventExecutor threads prior to scheduled task submission. Returns true if the EventExecutor thread should be woken immediately to process the scheduled task (if not already awake).

If false is returned, AbstractScheduledEventExecutor.afterScheduledTaskSubmitted(long) will be called with the same value after the scheduled task is enqueued, providing another opportunity to wake the EventExecutor thread if required.

Overrides:

beforeScheduledTaskSubmitted in class AbstractScheduledEventExecutor

Parameters:

deadlineNanos - deadline of the to-be-scheduled task relative to AbstractScheduledEventExecutor.getCurrentTimeNanos()

Returns:

true if the EventExecutor thread should be woken, false otherwise

afterScheduledTaskSubmitted

protected boolean afterScheduledTaskSubmitted(long deadlineNanos)

Description copied from class: AbstractScheduledEventExecutor

See AbstractScheduledEventExecutor.beforeScheduledTaskSubmitted(long). Called only after that method returns false.

Overrides:

afterScheduledTaskSubmitted in class AbstractScheduledEventExecutor

Parameters:

deadlineNanos - relative to AbstractScheduledEventExecutor.getCurrentTimeNanos()

Returns:

true if the EventExecutor thread should be woken, false otherwise

newTaskQueue

protected Queue<Runnable> newTaskQueue(int maxPendingTasks)

Description copied from class: SingleThreadEventExecutor

Create a new Queue which will holds the tasks to execute. This default implementation will return a LinkedBlockingQueue but if your sub-class of SingleThreadEventExecutor will not do any blocking calls on the this Queue it may make sense to @Override this and return some more performant implementation that does not support blocking operations at all.

Overrides:

newTaskQueue in class SingleThreadEventExecutor

getIoRatio

public int getIoRatio()

Returns the percentage of the desired amount of time spent for I/O in the event loop.

setIoRatio

public void setIoRatio(int ioRatio)

Sets the percentage of the desired amount of time spent for I/O in the event loop. The default value is 50, which means the event loop will try to spend the same amount of time for I/O as for non-I/O tasks.

registeredChannels

public int registeredChannels()

Description copied from class: SingleThreadEventLoop

Returns the number of Channels registered with this EventLoop or -1 if operation is not supported. The returned value is not guaranteed to be exact accurate and should be viewed as a best effort.

Overrides:

registeredChannels in class SingleThreadEventLoop

registeredChannelsIterator

public Iterator<Channel> registeredChannelsIterator()

Overrides:

registeredChannelsIterator in class SingleThreadEventLoop

Returns:

read-only iterator of active Channels registered with this EventLoop. The returned value is not guaranteed to be exact accurate and should be viewed as a best effort. This method is expected to be called from within event loop.

run

protected void run()

Description copied from class: SingleThreadEventExecutor

Runs the task-processing loop until SingleThreadEventExecutor.confirmShutdown() returns true.

Implementations must not let a Throwable thrown by a task escape this method: any uncaught Throwable terminates the executor (logged at WARN and surfaced via SingleThreadEventExecutor.terminationFuture()), at which point every Channel registered with this executor stops processing I/O and new task submissions are rejected. The supplied helpers - SingleThreadEventExecutor.runAllTasks(), SingleThreadEventExecutor.runAllTasks(long), and AbstractEventExecutor.safeExecute(Runnable) - catch Throwable for you; custom loops built on SingleThreadEventExecutor.pollTask() or SingleThreadEventExecutor.takeTask() are responsible for wrapping each task invocation accordingly.

Specified by:

run in class SingleThreadEventExecutor

cleanup

protected void cleanup()

Description copied from class: SingleThreadEventExecutor

Do nothing, sub-classes may override

Overrides:

cleanup in class SingleThreadEventExecutor

closeFileDescriptors

@UnstableApi
public void closeFileDescriptors()

This method is intended for use by process checkpoint/restore integration, such as OpenJDK CRaC. It's up to the caller to ensure that there is no concurrent use of the FDs while these are closed, e.g. by blocking the executor.