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

Jes Sorensen
2010-03-18T13:23:54Z

On 03/18/10 11:58, Ingo Molnar wrote:
>
> * Jes Sorensen<Jes.Sorensen@redhat.com> wrote:
>> Thats a very glorified statement but it's not reality, sorry. You can do
>> that with something like perf because it's so small and development of perf
>> is limited to a very small group of developers.
>
> I was not talking about just perf: i am also talking about the arch/x86/
> unification which is 200+ KLOC of highly non-trivial kernel code with hundreds
> of contributors and with 8000+ commits in the past two years.

Sorry but you cannot compare merging two chunks of kernel code that
originated from the same base, with the efforts of mixing a large
userland project with a kernel component. Apples and oranges.

> Also, it applies to perf as well: people said exactly that a year ago: 'perf
> has it easy to be clean as it is small, once it gets as large as Oprofile
> tooling it will be in the same messy situation'.
>
> Today perf has more features than Oprofile, has a larger and more complex code
> base, has more contributors, and no, it's not in the same messy situation at
> all.

Both perf and oprofile are still relatively small projects in comparison
to QEMU.

> So whatever you think of large, unified projects, you are quite clearly
> mistaken. I have done and maintained through two different types of
> unifications and the experience was very similar: both developers and users
> (and maintainers) are much better off.

You believe that I am wrong in my assessment of unified projects, and I
obviously think you are mistaken and underestimating the cost and
effects of trying to merge the two.

Well I think we are just going to agree to disagree on this one. I am
not against merging projects where it makes sense, but in this
particular case I am strongly convinced the loss would be much greater
than the gain.

Cheers,
Jes