Re: [Qemu-devel] [PATCH v3 0/3] virtio-mmio: introduce eventfd support

[Yingshiuan Pan]

Hi Peter,

I think this patch set was already merged by Michael in Jun. :).
http://git.qemu.org/?p=qemu.git;a=commit;h=434027badb421863b85ffdb4769966533c001cfa

--
Best Regards,
Yingshiuan Pan

2015-09-19 0:24 GMT+08:00 Peter Maydell :

> On 12 May 2015 at 09:10, Pavel Fedin  wrote:
> >  This patch set introduces eventfd support for virio-mmio. It was
> originally
> > published by Ying-Shiuan Pan but never got it to upstream:
> > https://lists.gnu.org/archive/html/qemu-devel/2014-02/msg00715.html
> >  I have updated and successfully tested it with vhost-net. I confirm
> that this
> > solution significantly improves the network performance even without
> irqfd.
> >  I would like to upstream it, since virtio-mmio is still there. I know
> that
> > some of you consider it deprecated, however i believe this is not
> entirely
> > true. Because you can add it to machine models which are not supposed to
> > have PCI (like vexpress).
> >  An old patch set relied on additional "eventfd" option in order to
> disable
> > the support if not implemented in kernel. My version simply checks
> > kvm_eventfds_enabled() for this purpose, so backwards compatibility is
> much
> > better.
> >  I decided to leave this set in three parts because ioeventfd support
> should
> > be enabled only when both host and guest notifiers are in place. I
> believe
> > it will not work with partial implementation, at least because vhost-net
> > requires both sets of eventfds. In this version i added correct reset
> handling.
>
> Hi Pavel. I've been going through my to-review folder and found this
> series from back in May lurking in it. Sorry I never got to reviewing it.
> Do you think it's still a change worth having? If so, please can you
> rebase and resend and I'll look at it this time around.
>
> thanks
> -- PMM
>

Re: [Qemu-devel] [PATCH v3 0/3] virtio-mmio: introduce eventfd support

[Peter Maydell]

On 12 May 2015 at 09:10, Pavel Fedin  wrote:
>  This patch set introduces eventfd support for virio-mmio. It was originally
> published by Ying-Shiuan Pan but never got it to upstream:
> https://lists.gnu.org/archive/html/qemu-devel/2014-02/msg00715.html
>  I have updated and successfully tested it with vhost-net. I confirm that this
> solution significantly improves the network performance even without irqfd.
>  I would like to upstream it, since virtio-mmio is still there. I know that
> some of you consider it deprecated, however i believe this is not entirely
> true. Because you can add it to machine models which are not supposed to
> have PCI (like vexpress).
>  An old patch set relied on additional "eventfd" option in order to disable
> the support if not implemented in kernel. My version simply checks
> kvm_eventfds_enabled() for this purpose, so backwards compatibility is much
> better.
>  I decided to leave this set in three parts because ioeventfd support should
> be enabled only when both host and guest notifiers are in place. I believe
> it will not work with partial implementation, at least because vhost-net
> requires both sets of eventfds. In this version i added correct reset 
> handling.

Hi Pavel. I've been going through my to-review folder and found this
series from back in May lurking in it. Sorry I never got to reviewing it.
Do you think it's still a change worth having? If so, please can you
rebase and resend and I'll look at it this time around.

thanks
-- PMM

Re: [Qemu-devel] [PATCH v3 0/3] virtio-mmio: introduce eventfd support

[Peter Maydell]

On 18 September 2015 at 17:56, Yingshiuan Pan  wrote:
> Hi Peter,
>
> I think this patch set was already merged by Michael in Jun. :).
> http://git.qemu.org/?p=qemu.git;a=commit;h=434027badb421863b85ffdb4769966533c001cfa

That answers that question :-). Thanks for digging up the git
commit for me.

-- PMM

[Qemu-devel] [PATCH v3 0/3] virtio-mmio: introduce eventfd support

[Pavel Fedin]

 This patch set introduces eventfd support for virio-mmio. It was originally
published by Ying-Shiuan Pan but never got it to upstream:
https://lists.gnu.org/archive/html/qemu-devel/2014-02/msg00715.html
 I have updated and successfully tested it with vhost-net. I confirm that this
solution significantly improves the network performance even without irqfd.
 I would like to upstream it, since virtio-mmio is still there. I know that
some of you consider it deprecated, however i believe this is not entirely
true. Because you can add it to machine models which are not supposed to
have PCI (like vexpress).
 An old patch set relied on additional eventfd option in order to disable
the support if not implemented in kernel. My version simply checks
kvm_eventfds_enabled() for this purpose, so backwards compatibility is much
better.
 I decided to leave this set in three parts because ioeventfd support should
be enabled only when both host and guest notifiers are in place. I believe
it will not work with partial implementation, at least because vhost-net
requires both sets of eventfds. In this version i added correct reset handling.



Ying-Shiuan Pan (3):
  virtio-mmio: introduce set_host_notifier()
  virtio-mmio: introduce set_guest_notifiers
  virtio-mmio: start ioeventfd when status gets DRIVER_OK

 hw/virtio/virtio-mmio.c | 181 
 1 file changed, 181 insertions(+)

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