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

Anthony Liguori
2010-03-18T14:53:26Z

On 03/18/2010 06:48 AM, Ingo Molnar wrote:
> * Avi Kivity<avi@redhat.com> wrote:
>
>
>> On 03/18/2010 12:50 PM, Ingo Molnar wrote:
>>
>>> * Avi Kivity<avi@redhat.com> wrote:
>>>
>>>
>>>>> The moment any change (be it as trivial as fixing a GUI detail or as
>>>>> complex as a new feature) involves two or more packages, development speed
>>>>> slows down to a crawl - while the complexity of the change might be very
>>>>> low!
>>>>>
>>>> Why is that?
>>>>
>>> It's very simple: because the contribution latencies and overhead compound,
>>> almost inevitably.
>>>
>> It's not inevitable, if the projects are badly run, you'll have high
>> latencies, but projects don't have to be badly run.
>>
> So the 64K dollar question is, why does Qemu still suck?
>

Why does Linux AIO still suck? Why do we not have a proper interface in
userspace for doing asynchronous file system operations?

Why don't we have an interface in userspace to do zero-copy transmit and
receive of raw network packets?

The lack of a decent userspace API for asynchronous file system
operations is a huge usability problem for us. Take a look at the
complexity of our -drive option. It's all because the kernel gives us
sucky interfaces.

Regards,

Anthony Liguori