Re: [Alacrityvm-devel] [GIT PULL] AlacrityVM guest drivers for 2.6.33

Gregory Haskins
2009-12-23T21:21:37Z

(Sorry for top post...on a mobile)

When someone repeatedly makes a claim you believe to be wrong and you
correct them, you start to wonder if that person has a less than
honorable agenda. In any case, I overreacted. For that, I apologize.

That said, you are still incorrect. With what I proposed, the model
will run as an in-kernel vbus device, and no longer run in userspace.
It would therefore improve virtio-net as I stated, much in the same
way vhost-net or venet-tap do today.

FYI I am about to log out for the long holiday, so will be
unresponsive for a bit.

Kind Regards,
-Greg

On 12/23/09, Avi Kivity <avi@redhat.com> wrote:
> On 12/23/2009 08:15 PM, Gregory Haskins wrote:
>> On 12/23/09 5:22 AM, Avi Kivity wrote:
>>
>>
>>> There was no attempt by Gregory to improve virtio-net.
>>>
>> If you truly do not understand why your statement is utterly wrong at
>> this point in the discussion, I feel sorry for you. If you are trying
>> to be purposely disingenuous, you should be ashamed of yourself. In any
>> case, your statement is demonstrably bogus, but you should already know
>> this given that we talked about at least several times.
>>
>
> There's no need to feel sorry for me, thanks. There's no reason for me
> to be ashamed, either. And there's no need to take the discussion to
> personal levels. Please keep it technical.
>
>
>> To refresh your memory: http://patchwork.kernel.org/patch/17428/
>>
>
> This is not an attempt to improve virtio-net, it's an attempt to push
> vbus. With this, virtio-net doesn't become any faster, since the
> greatest bottleneck is not removed, it remains in userspace.
>
> If you wanted to improve virtio-net, you would port venet-host to the
> virtio-net guest/host interface, and port any secret sauce in
> venet(-guest) to virtio-net. After that we could judge what vbus'
> contribution to the equation is.
>
>> In case its not blatantly clear, which I would hope it would be to
>> anyone that understands the problem space: What that patch would do is
>> allow an unmodified virtio-net to bridge to a vbus based virtio-net
>> backend. (Also note that this predates vhost-net by months (the date in
>> that thread is 4/9/2009) in case you are next going to try to argue that
>> it does nothing over vhost-net).
>>
>
> Without the backend, it is useless. It demonstrates vbus' flexibility
> quite well, but does nothing for virtio-net or its users, at least
> without a lot more work.
>
>> This would mean that virtio-net would gain most of the benefits I have
>> been advocating (fewer exits, cheaper exits, concurrent execution, etc).
>> So this would very much improve virtio-net indeed, given how poorly the
>> current backend was performing. I tried to convince the team to help me
>> build it out to completion on multiple occasions, but that request was
>> answered with "sorry, we are doing our own thing instead". You can say
>> that you didn't like my approach, since that is a subjective opinion.
>> But to say that I didn't attempt to improve it is a flat out wrong, and
>> I do not appreciate it.
>>
>
> Cutting down on the rhetoric is more important than cutting down exits
> at this point in time.
>
> --
> I have a truly marvellous patch that fixes the bug which this
> signature is too narrow to contain.
>
>

--
Sent from my mobile device