title: Boost Coroutines performance: Symmetric vs Asymmetric
body: <p>Looking at the <a href="http://www.boost.org/doc/libs/1_59_0/libs/coroutine/doc/html/coroutine/performance.html" rel="noreferrer">performance page of Boost.Coroutine</a>, symmetric coroutines seem to be significantly cheaper to construct than asymmetric ones, by about 50x. This seems surprising as symmetric coroutines seem to provide a more general abstraction. Is there some functionality in asymetric coroutines that justifies this cost?</p>
  
  <p>I should also add that, in the context of asymetric coroutines, the construction cost is about 500x the cost of a context switch, so it could easily be the bottleneck in an application.</p>