Longpolling (I think) is killing my local server

I am running a longpolling script to grab data from the database. It was working fine until moving my script to an MVC.

I have viewed the chrome developer tool and it's showing nothing in there, but the page just carries on loading, and when I go to refresh it won't load, I have to shit down my xampp server or close my browser... Here's my script:

<?php

class SystemController extends Controller
{

    public function lastbid()
    {

        set_time_limit(0);


        // main loop
        while (true) {


            //get the product info
            $getbidresult = ProductModel::bidprice(Request::get('item'));

            // if ajax request has send a timestamp, then $last_ajax_call = timestamp, else $last_ajax_call = null
            $last_ajax_call = Request::get('timestamp'); 


            // get timestamp of when file has been changed the last time
            $lastbid = isset($getbidresult->timestamp) ? $getbidresult->timestamp : 0;

            // if no timestamp delivered via ajax or data.txt has been changed SINCE last ajax timestamp
            if ($last_ajax_call == null || $lastbid > $last_ajax_call) {

            // put last bid info into an array
            $result = array(
                'bidamount' => isset($getbidresult->amount) ? System::escape($getbidresult->amount): 0,
                'timestamp' => System::escape($lastbid)
            );

            // encode to JSON, render the result (for AJAX)
            $json = json_encode($result);
            echo $json;

            // leave this loop step
            break;

        } else {
            // wait for 1 sec (not very sexy as this blocks the PHP/Apache process, but that's how it goes)
            sleep(10);
            continue;
        }
    }

    }
}

This is how I am grabbing the data with JS.

<script type="text/javascript">
function getContent(timestamp)
{
  var queryString = {
    'timestamp': timestamp
  };
  $.ajax(
  {
    type: 'GET',
    url: '<?php echo Config::get('URL'); ?>system/lastbid?item=<?php echo System::escape($recentitem->id); ?>',
    data: queryString,
    success: function(data)
    {
      var obj = jQuery.parseJSON(data);
      $('#bidprice-<?php echo System::escape($recentitem->id); ?>').html(obj.bidamount);
      getContent(obj.timestamp);
    }
  });
}
$(function()
{
  getContent();
});
$(document).ready(function() {
});
</script>

I've looked in apache logs with no avail unless I am looking in the wrong place. Does anything in the code look out of place, It doesn't to my knowledge but I may be overlooking something.

I have the script in a foreach, so I can initiate the div, for each product.