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IO::Async::Loop::Epoll.3pm

NAME

IO::Async::Loop::Epoll - use "IO::Async" with "epoll" on Linux

SYNOPSIS

  use IO::Async::Loop::Epoll;
 
  my $loop = IO::Async::Loop::Epoll->new();
 
  $loop->add( ... );
 
  $loop->add( IO::Async::Signal->new(
        name => 'HUP',
        on_receipt => sub { ... },
  ) );
 
  $loop->loop_forever();
 
 

DESCRIPTION

This subclass of "IO::Async::Loop" uses "IO::Epoll" to perform read-ready and write-ready tests so that the O(1) high-performance multiplexing of Linux's epoll_pwait(2) syscall can be used.

The "epoll" Linux subsystem uses a registration system similar to the higher level "IO::Poll" object wrapper, meaning that better performance can be achieved in programs using a large number of filehandles. Each epoll_pwait(2) syscall only has an overhead proportional to the number of ready filehandles, rather than the total number being watched. For more detail, see the epoll(7) manpage.

This class uses the epoll_pwait(2) system call, which atomically switches the process's signal mask, performs a wait exactly as epoll_wait(2) would, then switches it back. This allows a process to block the signals it cares about, but switch in an empty signal mask during the poll, allowing it to handle file IO and signals concurrently.

CONSTRUCTOR

$loop = IO::Async::Loop::Epoll->new()

This function returns a new instance of a "IO::Async::Loop::Epoll" object.

METHODS

As this is a subclass of IO::Async::Loop, all of its methods are inherited. Expect where noted below, all of the class's methods behave identically to "IO::Async::Loop".

$count = $loop->loop_once( $timeout )

This method calls the "poll()" method on the stored "IO::Epoll" object, passing in the value of $timeout, and processes the results of that call. It returns the total number of "IO::Async::Notifier" callbacks invoked, or "undef" if the underlying "epoll_pwait()" method returned an error. If the "epoll_pwait()" was interrupted by a signal, then 0 is returned instead.

SEE ALSO

•

IO::Epoll - Scalable IO Multiplexing for Linux 2.5.44 and higher

•

IO::Async::Loop::Poll - use IO::Async with poll(2)

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>