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

From: Jes Sorensen
Date: Thu Mar 18 2010 - 09:24:23 EST


On 03/18/10 11:58, Ingo Molnar wrote:

* Jes Sorensen<Jes.Sorensen@xxxxxxxxxx> 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/