title: why uwsgi workers idle but nginx showed a lot of timeouts?
body: <p>Stack: nginx, uwsgi, django</p>
  
  <p>uwsgitop and top both showed uwsgi workers are idle, while nginx error log said upstream timed out. </p>
  
  <p>I thought  some of request needed a lot of resources such as waiting for db or cache, while the others not.  After checking the timed out requests, most of them were not voracious. Any kind of request had been timed out. </p>
  
  <p>So why nginx didn't seed the requests to idle ones if the others were really busy? why uwsgi master just keep someone busy and the others idle?</p>