title: How to read Evaluate Script timings in Chrome profiling/performance tab
body: <p>I've been told that my script is blocking the main thread on my client's site.</p>
  
  <p>It's marked as <code>&lt;script async...&gt;</code> so it should not be a network block.</p>
  
  <p>I ran the Chrome profiler and I don't really understand what I'm looking at, despite googling for explanations.</p>
  
  <p>Here's a screenshot of the script in question:
  <a href="https://i.stack.imgur.com/jAlrv.png" rel="noreferrer"><img src="https://i.stack.imgur.com/jAlrv.png" alt="enter image description here"></a></p>
  
  <p>I don't understand which part of the entire blue block is the "thread blocking part"</p>
  
  <p>Here's the associated <code>Bottom-Up</code> table:
  <a href="https://i.stack.imgur.com/b3sP7.png" rel="noreferrer"><img src="https://i.stack.imgur.com/b3sP7.png" alt="enter image description here"></a></p>
  
  <p>From the first image, the "thin line" spans from around 500ms to around 900ms, which is around 400ms of time, but in the Bottom-Up table, it says the total "Evaluate Script" time is 184.5ms.</p>
  
  <p>So can I assume the "blocking" time of the script should be taken from the Bottom-Up table, coming up to be 184.5ms?</p>