Re: [PATCH 5/5] ioeventfd: Introduce KVM_IOEVENTFD_FLAG_SOCKET

Pekka Enberg
2011-07-14T08:59:09Z

On Thu, Jul 14, 2011 at 11:28 AM, Avi Kivity <avi@redhat.com> wrote:
> On 07/14/2011 11:14 AM, Pekka Enberg wrote:
>>
>> >
>> >  I'm talking about the real world.  Is any of this something that needs
>> >  optimization?
>>
>> Yes. See Sasha's other email. We should have mentioned that in the
>> changelog.
>
> It's completely unrealistic.  Sash and you are the only two people in the
> universe logging into the guest via a serial console and running benchmarks.

Why does that matter? Why should we keep the emulation slow if it's
possible to fix it? It's a fair question to ask if the benefits
outweigh the added complexity but asking as to keep serial emulation
slow because *you* think it's unrealistic is well - unrealistic from
your part!

>> >  1024 vcpus logging in via the serial console at 10Gbps.  Get real.
>>
>> [...]
>>
>> Huh, why are you bringing something like that up?
>
> Because it's another example of an unrealistic approach on your part.  No
> real user is interested in 1024 vcpus, and no real user is interested in
> optimized serial console.  It's good that you are bringing up new ideas and
> new code, but adding code just for its own sake is not a good thing.

*You* brought up 1024 vcpus using serial console! Obviously optimizing
something like that is stupid but we never claimed that we wanted to
do something like that!

As for 1024 vcpus, we already had the discussion where we explained
why we thought it was a good idea not to have such a low hard vcpu
limit for vcpus.

Pekka