Yes, the 10 ms would be CPU time, not wall time.

But still, 10 ms really is not a lot on a 600 MHz machine. How long does your front end take to serve one request? How many qps do you serve from a single instance?

I have some go code with a trivial, completely unoptimized blog, rendering a couple of articles. Poking at appstats suggests I spend a bit more than 10 ms CPU time, App Engine reports ~30 ms CPU time.