Re: Execute Jobs parallel using JobQueue

The other general advice is to use fork(), with or without POE, when  
you need true parallelism.

-- 
Rocco Caputo - [email protected]


On Dec 1, 2009, at 08:50, Mark Morgan wrote:

> Good day, Ryan,
>
> The problem with using 'sleep' in POE code is that POE isn't true
> pre-emptive multi-tasking, but rather cooperative multitasking at the
> process level.  Different sessions are still running in the same
> process/thread, so any actions that will monopolize CPU time for a
> stretch will block all POE tasks.  The general advice for POE tasks is
> that they should do no blocking calls in any individual event
> handling, in order to allow other sessions to run when the current one
> is idle.
>
> The best way to have a session delay itself for a time is one of the
> methods described in
> http://search.cpan.org/~rcaputo/POE-1.280/lib/POE/Kernel.pm#Timer_Events_%28Delayed_Messages%29
> .
>
> Take care,
> Mark.
>
> On Tue, Dec 1, 2009 at 4:38 PM, Ryan Chan <[email protected]>  
> wrote:
>> Hello,
>>
>> Consider my code below would like to execute the sleep() function in
>> parallel, using POE JobQueue component:
>>
>>
>> #=============
>> use strict;
>> use POE qw(Component::JobQueue);
>>
>> # Passive queue waits for enqueue events.
>> POE::Component::JobQueue->spawn(
>>        Alias       => 'passive',
>>        WorkerLimit => 16,
>>        Worker      => \&spawn_a_worker,
>>        Passive => {
>>                Prioritizer => sub { 1 }
>>        }
>> );
>>
>> sub spawn_a_worker {
>>        my ( $postback, @job_params ) = @_;
>>        POE::Session->create(
>>                inline_states => {
>>                        _start => \&start,
>>                        sleep  => \&sleep
>>                },
>>                args => [
>>                        $postback,
>>                        @job_params,
>>                ],
>>        );
>> }
>>
>> POE::Session->create(
>>        inline_states => {
>>                _start => \&init,
>>                _stop  => sub { print "END" }
>>        }
>> );
>> POE::Kernel->run();
>> exit(0);
>>
>> sub init {
>>        my $kernel = $_[KERNEL];
>>
>>        foreach ( 1 .. 10 ) {
>>                $kernel->post( passive => enqueue => response => $_ );
>>        }
>> }
>>
>> sub start {
>>        my $kernel = $_[ KERNEL ];
>>        print "Starting\n";
>>        $kernel->yield("sleep");
>> }
>>
>> sub sleep {
>>        print "Sleeping for 5 seconds\n";
>>        sleep 5;
>> }
>>
>> #==========
>>
>> It seems that tasks still block each other? If not, I would have all
>> message executed at the end of 5 seconds.
>>