LightVM is stating a VM creation of 2.3ms while Firecracker states 125ms of time from VM creation to a working user space. So this comparing apples and oranges.
I know it's cool to talk about these insane numbers, but from what I can tell people have AWS lambdas that boot slower than this to the point where people send warmup calls just to be sure. What exactly warrants the ability to start a VM this quickly?
The 125ms is using Linux. Using a unikernel and tweaking Firecracker a bit (on KraftCloud) we can get, for example, 20 millis cold starts for NGINX, and have features on the way to reduce this further.