title: How spinlocked threads avoid overhead of context switching?
body: <p>In wikipedia, the aritcle about spinlocks.</p>
  
  <blockquote>
    <p>Because they avoid overhead from operating system process rescheduling or context switching, spinlocks are efficient if threads are likely to be blocked for only short periods. </p>
  </blockquote>
  
  <p>I actually can't grasp this sentence.
  I think that even if a thread has a spinlock, it's going to be rescheduled, am I wrong ?
  <br><br>
  The context switching over-head - which is saving the registers,pc  &amp; scheduling queue - is constant for all switches, isn't it?</p>