I've set up Failed Request Tracing for a test site, but it is not measuring the speed the page takes to render.
It just says "Time Taken: 0 msec"
I've set up a similar test site on a different server and I do get a measurement for speed.
Failed Request Tracing should measure the speed the page takes to serve, right?
If you only want to benchmark the speed of a webpage, I recommend downloading fiddler
In regards to your problem seeing 0msec in FRT, you can try looking to see if you have the Output Caching module active. I have output caching enabled for images (.png) and saw a result of 0 msec just like your screenshot on subsequent runs.
The parameters for FRT I had enabled were: All Content (*), Status Code=200, Providers (all default).
ps. Try clearing your browser cache and do an
iisreset
from the command prompt and see if it updates.