Re: [ANNOUNCE] Native Linux KVM tool

From: Jan Kiszka
Date: Fri Apr 08 2011 - 05:12:19 EST

On 2011-04-08 10:27, Pekka Enberg wrote:
> Hi Jan,
> On Fri, 2011-04-08 at 09:39 +0200, Jan Kiszka wrote:
>> I agree that it's easy to change 2kSomething LOC for this. But if you
>> now wait too long designing in essential features like SMP, a scalable
>> execution model, and - very important - portability (*), it can get
>> fairly painful to fix such architectural deficits later on. How long did
>> it take for Linux to overcome the BKL? QEMU is in the same unfortunate
>> position.
> Yup, and we're taking your feedback seriously (and are thankful for
> it!). We're hoping to look at SMP in the near future - help is
> appreciated!

Honestly, I do not yet see a major advantage for us to invest here
instead of / in addition to continuing to improve QEMU. We've spend
quite some effort on the latter with IMO noteworthy results. Porting
over qemu-kvm to upstream was and still is among those efforts. We (*)
are "almost done". :)

Just one example: Despite QEMU's current deficits, I just have add a
handful of (ad-hoc) patches to turn it into a (soft) real-time
hypervisor, and that also for certain non-Linux guests. Your approach is
yet man years of development and stabilization effort away from getting
close to such a level.

Don't want to discourage you or other contributors. I wish you that this
approach can gather the critical mass and momentum to make it a real
alternative, at least for a subset of use cases. We will surely keep an
eye on it and re-assess its pros&cons as it progresses.


(*) the QEMU & KVM community

Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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