Threads are not equal. The game thread, or the rendering thread, are often much more important and a bottleneck. Many systems are parallelised and can happen on both named threads and worker threads. E.g. for a higher level overview, I’m trying to figure out how much time per frame a particular trace takes, that happens many times a frame, on both GT and worker threads.
It would help a lot to be able to see data only for a particular thread in Unreal Insights. E.g. in Timers tab header, between “Group By” and “Mode” combo boxes, another combo box, e.g. “Thread”, with values like “All”, “Game Thread”, “Rendering Thread”, “Worker Threads” etc. So when “Game Thread” is selected, only traces that happened on GT would be listed in “Timers”, and when a trace is plotted on the main graph, it would show only timing for GT.
It is possible to achieve this with existing functionality, by hiding all other CPU Thread tracks in the Timing View. The aggregated values in the Timers panel are computed only for the visible tracks. The graph track series for a timer also uses the visible tracks (so it will update automatically when a CPU Thread track is hidden).
So, to do this you can use the “CPU/GPU” drop down menu -- to hide all CPU thread tracks at once (or use the U key shortcut) and then to make visible only the thread groups needed (ex. the Game Thread; also from same CPU/GPU drop down menu), or to make only certain track visible (i.e. from a thread group with multiple threads) using the “All Tracks” drop down menu.
This workflow is not as easy as having a drop down with the thread filter as you suggested. I’ll add this to our backlog.