scomes(8) [centos man page]

scomes(8)						Tool for watching system resources						 scomes(8)

NAME

       scomes - tool for watching system resources

SYNOPSIS

       scomes -c "binary [binary arguments ...]" [timer]

DESCRIPTION

       scomes is a simple systemtap script for watching activity of one process. Syscalls count, userspace and kernelspace ticks, read and written
       bytes, transitted and received bytes and polling syscalls are measured.

       binary Binary file to be executed. This process will be watched.

       timer  Setting this option causes the script to print out statistic every N seconds. If not provided, the statistics are printed only  when
	      watched process terminates.

SEE ALSO

       tuned(8) diskdevstat(8) netdevstat(8) varnetload(8) stap(1)

AUTHOR

       Written by Jan Hutar <jhutar@redhat.com>.

REPORTING BUGS

       Report bugs to <pknirsch@redhat.com>.

Phil Knirsch							    13 Jan 2011 							 scomes(8)

Mojo::Reactor(3pm)					User Contributed Perl Documentation					Mojo::Reactor(3pm)

NAME

       Mojo::Reactor - Low level event reactor base class

SYNOPSIS

	 package Mojo::Reactor::MyEventLoop;
	 use Mojo::Base 'Mojo::Reactor';

	 $ENV{MOJO_REACTOR} ||= 'Mojo::Reactor::MyEventLoop';

	 sub io 	{...}
	 sub is_running {...}
	 sub one_tick	{...}
	 sub recurring	{...}
	 sub remove	{...}
	 sub start	{...}
	 sub stop	{...}
	 sub timer	{...}
	 sub watch	{...}

	 1;

DESCRIPTION

       Mojo::Reactor is an abstract base class for low level event reactors.

EVENTS

       Mojo::Reactor can emit the following events.

   "error"
	 $reactor->on(error => sub {
	   my ($reactor, $err) = @_;
	   ...
	 });

       Emitted safely for exceptions caught in callbacks.

	 $reactor->on(error => sub {
	   my ($reactor, $err) = @_;
	   say "Something very bad happened: $err";
	 });

METHODS

       Mojo::Reactor inherits all methods from Mojo::EventEmitter and implements the following new ones.

   "detect"
	 my $class = Mojo::Reactor->detect;

       Detect and load the best reactor implementation available, will try the value of the "MOJO_REACTOR" environment variable, Mojo::Reactor::EV
       or Mojo::Reactor::Poll.

	 # Instantiate best reactor implementation available
	 my $reactor = Mojo::Reactor->detect->new;

   "io"
	 $reactor = $reactor->io($handle => sub {...});

       Watch handle for I/O events, invoking the callback whenever handle becomes readable or writable. Meant to be overloaded in a subclass.

	 # Callback will be invoked twice if handle becomes readable and writable
	 $reactor->io($handle => sub {
	   my ($reactor, $writable) = @_;
	   say $writable ? 'Handle is writable' : 'Handle is readable';
	 });

   "is_readable"
	 my $success = $reactor->is_readable($handle);

       Quick non-blocking check if a handle is readable, useful for identifying tainted sockets.

   "is_running"
	 my $success = $reactor->is_running;

       Check if reactor is running. Meant to be overloaded in a subclass.

   "one_tick"
	 $reactor->one_tick;

       Run reactor until an event occurs or no events are being watched anymore. Note that this method can recurse back into the reactor, so you
       need to be careful.  Meant to be overloaded in a subclass.

	 # Don't block longer than 0.5 seconds
	 my $id = $reactor->timer(0.5 => sub {});
	 $reactor->one_tick;
	 $reactor->remove($id);

   "recurring"
	 my $id = $reactor->recurring(0.25 => sub {...});

       Create a new recurring timer, invoking the callback repeatedly after a given amount of time in seconds. Meant to be overloaded in a
       subclass.

	 # Invoke as soon as possible
	 $reactor->recurring(0 => sub { say 'Reactor tick.' });

   "remove"
	 my $success = $reactor->remove($handle);
	 my $success = $reactor->remove($id);

       Remove handle or timer. Meant to be overloaded in a subclass.

   "start"
	 $reactor->start;

       Start watching for I/O and timer events, this will block until "stop" is called or no events are being watched anymore. Meant to be
       overloaded in a subclass.

   "stop"
	 $reactor->stop;

       Stop watching for I/O and timer events. Meant to be overloaded in a subclass.

   "timer"
	 my $id = $reactor->timer(0.5 => sub {...});

       Create a new timer, invoking the callback after a given amount of time in seconds. Meant to be overloaded in a subclass.

	 # Invoke as soon as possible
	 $reactor->timer(0 => sub { say 'Next tick.' });

   "watch"
	 $reactor = $reactor->watch($handle, $readable, $writable);

       Change I/O events to watch handle for with "true" and "false" values, meant to be overloaded in a subclass.

	 # Watch only for readable events
	 $reactor->watch($handle, 1, 0);

	 # Watch only for writable events
	 $reactor->watch($handle, 0, 1);

	 # Watch for readable and writable events
	 $reactor->watch($handle, 1, 1);

	 # Pause watching for events
	 $reactor->watch($handle, 0, 0);

SEE ALSO

       Mojolicious, Mojolicious::Guides, <http://mojolicio.us>.

perl v5.14.2							    2012-09-05							Mojo::Reactor(3pm)