Re^4: Need help with Perl multi threading

[ashok.g]

in reply to Re^3: Need help with Perl multi threading
in thread Need help with Perl multi threading

Now this code:

#!/usr/bin/perl

use threads;
use strict;
use warnings;
use Net::SSH::Expect;
require 'total.pl';

my @servers = ('192.168.0.18','192.168.0.19','192.168.0.20');
my @process = ('testing','b','c');
my @threads;
my $output;
my $res;
my $final;
#@output = threads->new(\&Process_Output, $ssh, $proc )->join();

foreach my $host ( @servers )
{
    threads->new(\&process, $host )->join();
}
sub process()
{
    my $host = shift;
    my $png = `ping -c1 $host`;
    if ( $png =~ /64 bytes/ )
    {
        my $user= 'netcool';
                my $ssh = &SSH_Reference($host,$user);
        $ssh->run_ssh();
                eval {$res=$ssh->read_all(); };
        if ( !$@ && $res !~ /\(yes\/no\)/ && $res !~ m/password/ )
        {
            print "\nLogged in to $host\n";
                foreach my $proc ( @process ) 
                {
                    #push (@threads, threads->new(\&Process_Output, $s
+sh, $proc ));
                    $output=&Process_Output($ssh, $proc );
                        #print @output;
                        if ( $output =~ m/$proc/ )
                                        {
                                                print "\t$proc is runn
+ing\n";
                                        }
                                        else
                                        {
                                                print "\t$proc is not 
+running\n";
                                        }
                }
            $ssh->close();
        }
        else
        {
            print "Unable to SSH to $host\n";
        }
    }
    else
    {
        print "\nUnable to ping to Host: $host\n";
    }
}

produces this output:

perl some.pl 
Unable to SSH to 192.168.0.18
Unable to SSH to 192.168.0.19
Unable to SSH to 192.168.0.20

Now again back to the stage where I have started my script....

[chromatic]

With regard to:

foreach my $host ( @servers )
{
    threads->new(\&process, $host )->join();
}

... creating a new thread and then immediately joining it is a waste of time; join waits for the thread to finish.

In this case, detach is probably better. Otherwise, keep an array of all threads and after you've created all of them, then join all of them.

[ashok.g]

This was completely opposite to the comment posted in this node

Anyways I got my task completed by using Net::OpenSSH.

Thanks,
Ashok

[chromatic]

BrowserUK and I said essentially the same thing. If you write your thread code as you did, you're not getting any advantage of threading. All of your threads will run serially.