Understanding process breakdown

Dear community,

I need your help to have a better understaing of what process breakdown categories means.

I would like to have a link to documentation or at least a summary of these categories:


And these events:

]Function Call
]Evaluate Script
[]Recalculate Styles

Thank you all in advance for answering.


Those are just a breakdown of the Chrome Timeline. The dev tools docs are probably your best resource for that: https://developers.google.com/chrome-developer-tools/docs/timeline

Hi Webpagetest Team, I have found some differences between the results shown in the timeline view and the ones given directly on the Chrome Dev Tools. I understand the Breakdown timeline may not show all the detail information, but 1. why is the “Composite Layout” task not appearing like the scripting, rendering and paint tasks? Furthermore, 2. I have noticed that above a “click” event task there is always a “Animation Frame Fired” task. When i record the same event directly on Chrome dev tools this task does not appear(at least not over the “click” event task).

Here the timeline example:
Here the full test:

Thanks a lot!! :slight_smile: