Re: [Qemu-devel] [RFC PATCH] virtio-mmio: support for multiple irqs

[Joel Schopp]

On 11/05/2014 03:12 AM, Shannon Zhao wrote:
> Hi Rémy,
>
> On 2014/11/5 16:26, GAUGUEY Rémy 228890 wrote:
>> Hi Shannon, 
>>
>>> Type of backend         bandwith(GBytes/sec)
>>> virtio-net              0.66
>>> vhost-net               1.49
>>> vhost-net with irqfd    2.01
>>>
>>> Test cmd: ./iperf -c 192.168.0.2 -P 1 -i 10 -p 5001 -f G -t 60
>> Impressive results !
>> Could you please detail your setup ? which platform are you using and which 
>> GbE controller ?
> Sorry for not telling the test scenario. This test scenario is from Host to 
> Guest. It just
> compare the performance of different backends. I did this test on ARM64 
> platform.
>
> The setup was based on:
> 1)on host kvm-arm should support ioeventfd and irqfd
>       The irqfd patch is from Eric "ARM: KVM: add irqfd support".
>       http://www.spinics.net/lists/kvm-arm/msg11014.html
>
>       The ioeventfd patch is reworked by me from Antonios.
>       http://www.spinics.net/lists/kvm-arm/msg08413.html
>
> 2)qemu should enable ioeventfd support for virtio-mmio
>       This patch is refer to Ying-Shiuan Pan and reworked for new qemu branch.
>       https://lists.gnu.org/archive/html/qemu-devel/2014-11/msg00594.html
>
> 3)qemu should enable multiple irqs for virtio-mmio
>       This patch isn't sent to qemu maillist as we want to check whether this 
> is the right direction.
>       If you want to test, I'll send it to you.
I'm not a maintainer so my opinion isn't worth a lot here, but this
seems like the right direction to me.  I'd like to see the qemu patch
(do mention the dependency on the kernel patch) on the qemu-devel
mailing list.  I think these numbers also support some of the prereqs
listed above that have gone through several iterations getting queued up
for 3.19.