title: BlockingIOError exception ignored; should I be concerned?
body: <p>I'm writing a script that is 20,000 tasks that each make a subprocess call and a TCP call or two.  To make this not take all day, I'm using Python's new <code>asyncio</code>.</p>
  
  <p>However, I'm concerned about these errors Python prints out while my script runs:</p>
  
  <pre><code>Exception ignored when trying to write to the signal wakeup fd:
  BlockingIOError: [Errno 11] Resource temporarily unavailable
  </code></pre>
  
  <p>It will print a bunch of them, but not raise any exceptions.  I did get <code>OSError</code>s about <code>Too many open files</code> and dropped connections with the servers before, but I used semaphores to only allow 100 connections to each server at a time and only 700 connections total.</p>
  
  <p>Since Python's not raising any exceptions, I can't catch the errors.  But it doesn't <em>seem</em> to affect the script.</p>
  
  <p><strong>Are these errors something I should be concerned about?</strong>  If so, what do I need to do to get rid of them?  If not, how do I get rid of them so they're not in my program's output?</p>
  
  <p>Also, if these errors are serious, why does Python ignore them instead of raising an exception?</p>