Re: [Qemu-devel] The status about vhost-net on kvm-arm?

[Nikolay Nikolaev]

Hello,


On Tue, Aug 12, 2014 at 5:41 AM, Li Liu <address@hidden> wrote:
>
> Hi all,
>
> Is anyone there can tell the current status of vhost-net on kvm-arm?
>
> Half a year has passed from Isa Ansharullah asked this question:
> http://www.spinics.net/lists/kvm-arm/msg08152.html
>
> I have found two patches which have provided the kvm-arm support of
> eventfd and irqfd:
>
> 1) [RFC PATCH 0/4] ARM: KVM: Enable the ioeventfd capability of KVM on ARM
> http://lists.gnu.org/archive/html/qemu-devel/2014-01/msg01770.html
>
> 2) [RFC,v3] ARM: KVM: add irqfd and irq routing support
> https://patches.linaro.org/32261/
>
> And there's a rough patch for qemu to support eventfd from Ying-Shiuan Pan:
>
> [Qemu-devel] [PATCH 0/4] ioeventfd support for virtio-mmio
> https://lists.gnu.org/archive/html/qemu-devel/2014-02/msg00715.html
>
> But there no any comments of this patch. And I can found nothing about qemu
> to support irqfd. Do I lost the track?
>
> If nobody try to fix it. We have a plan to complete it about virtio-mmio
> supporing irqfd and multiqueue.
>
>

we at Virtual Open Systems did some work and tested vhost-net on ARM
back in March.
The setup was based on:
 - host kernel with our ioeventfd patches:
http://www.spinics.net/lists/kvm-arm/msg08413.html

- qemu with the aforementioned patches from Ying-Shiuan Pan
https://lists.gnu.org/archive/html/qemu-devel/2014-02/msg00715.html

The testbed was ARM Chromebook with Exynos 5250, using a 1Gbps USB3
Ethernet adapter connected to a 1Gbps switch. I can't find the actual
numbers but I remember that with multiple streams the gain was clearly
seen. Note that it used the minimum required ioventfd implementation
and not irqfd.

I guess it is feasible to think that it all can be put together and
rebased + the recent irqfd work. One can achiev even better
performance (because of the irqfd).

>
>
>
>
>
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regards,
Nikolay Nikolaev
Virtual Open Systems