Parallel task sink in PHP

<?php
/*
* Task sink
* Binds PULL socket to tcp://localhost:5558
* Collects results from workers via that socket
* @author Ian Barber <ian(dot)barber(at)gmail(dot)com>
*/

// Prepare our context and socket
$context = new ZMQContext();
$receiver = new ZMQSocket($context, ZMQ::SOCKET_PULL);
$receiver->bind("tcp://*:5558");

// Wait for start of batch
$string = $receiver->recv();

// Start our clock now
$tstart = microtime(true);

// Process 100 confirmations
$total_msec = 0; // Total calculated cost in msecs
for ($task_nbr = 0; $task_nbr < 100; $task_nbr++) {
$string = $receiver->recv();
if ($task_nbr % 10 == 0) {
echo ":";
} else {
echo ".";
}
}

$tend = microtime(true);

$total_msec = ($tend - $tstart) * 1000;
echo PHP_EOL;
printf ("Total elapsed time: %d msec", $total_msec);
echo PHP_EOL;