Re: [RFC] Unify KVM kernel-space and user-space code into a single project

Ingo Molnar
2010-03-22T12:22:37Z

* oerg Roedel <joro@8bytes.org> wrote:

> On Sun, Mar 21, 2010 at 09:31:21PM +0100, Ingo Molnar wrote:
> > Lets see one example of that thought process in action: Oprofile.
>
> Since you are talking so much about oProfile in this thread I think it is
> important to mention that the problem with oProfile was not the repository
> separation.
>
> The problem was (and is) that the kernel and the user-space parts are
> maintained by different people [...]

Caused by: repository separation and the inevitable code and social fork a
decade later.

> [...] who dont talk to each other or have a direction where they want to go
> with the project. [...]

Caused by: repository separation and the inevitable code and social fork a
decade later.

> [...] Basically the reason of the oProfile failure is a disfunctional
> community. [...]

Caused by: repository separation and the inevitable code and social fork a
decade later.

> [...] I told the kernel-maintainer several times to also maintain
> user-space but he didn't want that.
>
> The situation with KVM is entirely different. Avi commits to kvm.git and
> qemu-kvm.git so he maintains both. [...]

What you fail to realise (or what you fail to know, you werent around when
Oprofile was written, i was) is that Oprofile _did_ have a functional single
community when it was written. The tooling and the kernel bits was written by
the same people.

But a decade is a long time and the drift happened due to the inevitability of
the repository separation, and due to the _inability_ to reach a sane, usable
solution within that framework of separation.

So i dont see much of a difference to the Oprofile situation really and i see
many parallels. I also see similar kinds of desktop usability problems.

The difference is that we dont have KVM with a decade of history and we dont
have a 'told you so' KVM reimplementation to show that proves the point. I
guess it's a matter of time before that happens, because Qemu usability is so
absymal today - so i guess we should suspend any discussions until that
happens, no need to waste time on arguing hypoteticals.

I think you are rationalizing the status quo.

It's as if you argued in 1990 that the unification of East and West Germany
wouldnt make much sense because despite clear problems and incompatibilites
and different styles westerners were still allowed to visit eastern relatives
and they both spoke the same language after all ;-)

Thanks,

Ingo