Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35?

[Anthony Liguori]

On 08/03/2010 12:58 PM, Avi Kivity wrote:
>  On 08/03/2010 08:42 PM, Anthony Liguori wrote:
> > However, I don't think we can objectively differentiate between a 
> > "major" and "minor" user.  Generally speaking, I would rather that we 
> > not take the position of "you are a minor user therefore we're not 
> > going to accommodate you".
>
> Again it's a matter of practicalities.  With have written virtio 
> drivers for Windows and Linux, but not for FreeDOS or NetWare.  To 
> speed up Windows XP we have (in qemu-kvm) kvm-tpr-opt.c that is a 
> gross breach of decency, would we go to the same lengths to speed up 
> Haiku?  I suggest that we would not.

tpr-opt optimizes a legitimate dependence on the x86 architecture that 
Windows has.  While the implementation may be grossly indecent, it 
certainly fits the overall mission of what we're trying to do in qemu 
and kvm which is emulate an architecture.

You've invested a lot of time and effort into it because it's important 
to you (or more specifically, your employer).  That's because Windows is 
important to you.

If someone as adept and commit as you was heavily invested in Haiku and 
was willing to implement something equivalent to tpr-opt and also 
willing to do all of the work of maintaining it, then reject such a 
patch would be a mistake.

If Richard is willing to do the work to make -kernel perform faster in 
such a way that it fits into the overall mission of what we're building, 
then I see no reason to reject it.  The criteria for evaluating a patch 
should only depend on how it affects other areas of qemu and whether it 
impacts overall usability.

As a side note, we ought to do a better job of removing features that 
have created a burden on other areas of qemu that aren't actively being 
maintained.  That's a different discussion though.

Regards,

Anthony Liguori