Sure, but ngen solved that problem years ago: http://msdn.microsoft.com/en-us/library/6t9t5wcf(v=vs.110).a...

Yeah, and mono's AOT too. I wonder if this is really just ngen integration into VS and thus not really a big deal.

See https://news.ycombinator.com/item?id=7520687

So I guess this is ngen in the cloud to skip doing it on the PC.

If I remember ngen is very architecture/platform specific - that is why it has to be done on the target machine. This sounds like it is done ahead of time with support for a variety of architectures.

It seems like this is basically just the same thing that Mono has done for a long time with AOT. I'm not really sure how it differs from the Ngen tool, though.

.NET Native addresses many of the same issues as Mono AOT but it has a radically different basis. We had the advantage of hindsight :)

The biggest difference with NGen is the fact that .NET Native doesn't ever "fall back" to JIT compiled code. There are other differences--refactored runtime, static-optimized libraries, static marshalling, etc.--which can be seen by the perf wins over NGen. We're seeing 40% startup performance gain over NGen apps for top Windows Store apps.

@apardoe, one question: where will the compilation to machine instruction happen? From some comments in this thread, it seems that it will happen at app store server and not at developer's box. If that is the case then why will I need anything to do any settings in VS for building projects?

@rajeevk, we could compile from MSIL and not tell the developer. But you probably appreciate the chance to test out the app on your own the way your user will run it. After all, you'll want to profile it or maybe find that last on-device, optimized-only bug...

What about stuff like Il.Emit and Expression<T>.Compile

Reflection.Emit isn't allowed in the Windows Store profile so we haven't handled it in this go-around. Expression compile is supported and handled properly.