title: why does SwiftMQ show flow control behaviour even when flow control is disabled?
body: <p>I'm trying to benchmark the performance of swiftMQ 5.0.0 with producer and consumer application I wrote so that I can vary the number of producer threads and consumer threads. I have added a delay on the consumer to simulate the time taken to process a message. I have run a test by setting the producer threads fixed at 2, and by varying the number of consumer threads from 20 to 92 in steps of 4.</p>
  <p>Initially, the producer rate starts high and consumer rate is low (as expected due to the delay added and less number of consumer threads).</p>
  <p>As the number of consumer threads increase, the producer rate drops and consumer rate increases and they become equal at around 48 consumer threads.</p>
  <p>After that, as the number of consumer threads further increase, both producer and consumer rates keep increasing linearly. <strong>I am wandering what the reason for this behavior is?</strong></p>
  <p>see this image for the
  <a href="https://i.stack.imgur.com/WmRFi.png" rel="nofollow noreferrer">result graph</a></p>
  <p>Notes:</p>
  <ul>
  <li>I have disabled flow control at queue level by setting <code>flowcontrol-start-queuesize=&quot;-1&quot;</code> .</li>
  <li>I also have not set a value to <code>inbound-flow-control-enabled</code> in routing swiftlet. (I believe it
  defaults to false)</li>
  </ul>
  <p>Any help on this matter is much appreciated. TIA</p>