Re^4: Queuing in multithread context

Thank you again for your guidance,

problem is to me that I'm unable to find a pattern where I can achieve a working implementation of your sample. This is a great sample of queueing proved working but I just don't get it, maybe I just completely mistaken the purpose of the Thread::Queue; ... I understood it could hold threads (like tasks) waiting for the completion of one to dequeue a second..

To be honest what is losing me in your example is that you never "queue" any item in $serverQueue... there is something I don't get in here, maybe this is a bit too advanced for my understanding

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Re^5: Queuing in multithread context by SimonPratt (Friar) on Jan 20, 2015 at 18:39 UTC
Added some comments to help you out: use 5.16.2; use threads; use Thread::Queue; my @serverList = qw(one two three four five six); # Array to hold list + of servers that need to be updated my $serverQueue = Thread::Queue->new( @serverList ); # Create a Thread +::Queue, passing in the array of servers as items to queue (each serv +er is queued as a single string) $serverQueue->end; # Nothing else will be queued, so notify the queue +of this by ending it my @threads = map { threads->new( \&worker ) } 1..4; # Create a suitab +le number of threads that wont overload IO on the local server $_->join for @threads; # Block here until all the threads have complet +ed say 'Back to main - Finished!'; # End of program sub worker { my $tid = threads->tid; # Get the ID number of the thread while ( my $server = $serverQueue->dequeue_nb ) { # Dequeue the ne +xt item from the queue, in a non-blocking fashion (will undef and fin +ish loop once the queue is empty) say "I'm thread ID $tid and I'm processing server $server"; sleep 1; } say "Thread ID $tid finished"; } [download]	[reply] [d/l]

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Re^5: Queuing in multithread context
by SimonPratt (Friar) on Jan 20, 2015 at 18:39 UTC

Added some comments to help you out:

use 5.16.2;
use threads;
use Thread::Queue;

my @serverList = qw(one two three four five six); # Array to hold list
+ of servers that need to be updated

my $serverQueue = Thread::Queue->new( @serverList ); # Create a Thread
+::Queue, passing in the array of servers as items to queue (each serv
+er is queued as a single string)
$serverQueue->end; # Nothing else will be queued, so notify the queue 
+of this by ending it

my @threads = map { threads->new( \&worker ) } 1..4; # Create a suitab
+le number of threads that wont overload IO on the local server
$_->join for @threads; # Block here until all the threads have complet
+ed

say 'Back to main - Finished!'; # End of program

sub worker {
    my $tid = threads->tid; # Get the ID number of the thread
    while ( my $server = $serverQueue->dequeue_nb ) { # Dequeue the ne
+xt item from the queue, in a non-blocking fashion (will undef and fin
+ish loop once the queue is empty)
        say "I'm thread ID $tid and I'm processing server $server";
        sleep 1;
    }
    say "Thread ID $tid finished";
}
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