When a thread updates a shared variable, the main thread will not see the update until it reads the shared variable again. A common way to do this is to have a timer in the Tk GUI to read the shared variable every 10 milliseconds( or whatever rate is good enough for you). You don't show any real code involving sockets, but Simple threaded chat server might help you with some ideas.

A simple example of a timer based method:

#!/usr/bin/perl
use warnings;
use strict;
use threads;
use threads::shared;

# declare, share then assign
my $ret;
share $ret;
$ret = 0;
my $val = 0;

#create thread before any tk code is called
my $thr = threads->create( \&worker );

use Tk;
my $mw = MainWindow->new();

    my $label = $mw->Label(
         -width => 50,
         -textvariable => \$val )->pack();
 
    my $timer = $mw->repeat(10,sub{
              $val = $ret;
            });

MainLoop;


# no Tk code in thread
sub worker {
   for(1..10){
     print "$_\n"; 
     $ret = $_;
     sleep 1; 
    }
   $ret = 'thread done, ready to join';
   print "$ret\n";
}
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Thanks for the information. I was able to do this by using the perl cond_wait and cond_signal concept.

Im not very good in threads. Kindly provide your suggestion on this

Perlmonks is not a code writing service, rather we help you to help yourself.

So I suggest you learn about threads by reading perlthrtut, try to do what you want, and come back with more specific questions when you're stuck.

I went through the link. It was very usefule. Even I manage to solve this using cond_signal and cond_Wait concept. Thanks once again for helping to refer this link.