I'm using build timeout plugin and there's evident that the build time includes the time a job spent waiting in the build queue.

Let say I have build timeout set to 6 hours. But my job was actually executed for 1 hour or so before the build timeout plugin kicked in and killed it. So that 5 hour difference was actually spent in the build queue waiting for a available slave.

I think it makes more sense to assume build time start ticking only when the job executes