Re: [Qemu-devel] [PATCH] main: force enabling of I/O thread

[Anthony Liguori]

On 08/29/2011 03:21 PM, Andreas Färber wrote:
> Am 29.08.2011 um 20:03 schrieb Anthony Liguori:
>
> > On 08/22/2011 08:35 AM, Jan Kiszka wrote:
> > > On 2011-08-22 15:24, Anthony Liguori wrote:
> > > > Enabling the I/O thread by default seems like an important part of
> > > > declaring
> > > > 1.0. Besides allowing true SMP support with KVM, the I/O thread
> > > > means that the
> > > > TCG VCPU doesn't have to multiplex itself with the I/O dispatch
> > > > routines which
> > > > currently requires a (racey) signal based alarm system.
> > > >
> > > > I know there have been concerns about performance. I think so far
> > > > the ones that
> > > > have come up (virtio-net) are most likely due to secondary reasons like
> > > > decreased batching.
> > >
> > > iothread enabled without [1] gives unacceptable performance for ARM
> > > emulation (Musicpal board) here. With that series applied, the host CPU
> > > load is measurably higher, but no longer excessively.
> >
> > Given that [1] has been applied now, is there any objections to this
> > patch?
>
> There had been additional patches to fix I/O thread issues on Darwin,
> have any such fixes been applied the last few weeks?

I don't see any outstanding Darwin patches in my queue so either they 
were applied or there were issues with them.

Regards,

Anthony Liguori

> The patches that I tested some time ago only fixed the non-iothread case
> reliably.
>
> Andreas