Zerg demo – Xen instance spawned for each web request
zerg.erlangonxen.org
zerg.erlangonxen.org
It's not an easy problem to solve elegantly too.
Edit: I wonder if the numbers would be similar if the example was done with HaLVM (https://github.com/GaloisInc/HaLVM).
I tweaked the background image URLs so they'd be absolute instead of relative, but otherwise it's unmodified.
Because 1.5 secs per request, and more for somewhat more complex operations, seems long to me. As instance startup time it is impressive though! But they are designed to die after each request, right? Or is that just this example?
But that isn't 3 seconds to serve the page. That's 3 seconds to basically build and boot the "server" on-demand, start all necessary daemons and serve the page.
Now think about what happened when you needed to add a Web server 10 years ago.
When you need to scale in a hurry (or in this case semi-automatically), the ability to launch persistent or temporary VM instances in a much shorter timeframe is critical.
Granted (and as they note here) this is sort of demo-only, and probably not particularly useful out of the box. But as a demonstration of how fast things could work it's perfect. It doesn't hurt that it's functional.
EDIT: Their github commit is fairly active for a solo developer[2].
These are very different things.