Re: [Qemu-devel] Lock contention in QEMU

[Weiwei Jia]

On Fri, Dec 16, 2016 at 4:48 AM, Stefan Hajnoczi <address@hidden> wrote:
> On Thu, Dec 15, 2016 at 11:04:23AM -0500, Weiwei Jia wrote:
>> On Thu, Dec 15, 2016 at 3:06 AM, Stefan Hajnoczi <address@hidden> wrote:
>> > On Thu, Dec 15, 2016 at 12:17:09AM -0500, Weiwei Jia wrote:
>> >> BTW, do we have an example to show users how to config following
>> >> virtio-blk dataplane commands into XML configuration file?
>> >>
>> >> qemu -object iothread,id=iothread0 \
>> >>       -drive if=none,id=drive0,file=test.img,format=raw,cache=none \
>> >>       -device virtio-blk-pci,iothread=iothread0,drive=drive0
>> >
>> > https://libvirt.org/formatdomain.html#elementsIOThreadsAllocation
>> >
>> > See also <cputune><iothreadpin> and <driver iothread=>.
>>
>> It seems that the libvirt XML configuration in above link [1] is
>> different from the configuration which you said in your blog [2]. Your
>> blog just said how to use x-data-plane for virtio-blk but libvirt XML
>> configuration doesn't say anything about x-data-plane. Does it in
>> default support by latest QEMU version. If I want to test virtio-blk
>> or virtio-scsi data-plane to make timeslice more stable, what version
>> of QEMU/KVM should I use? Would you please give me some suggestions?
>> Thank you.
>>
>> [1] https://libvirt.org/formatdomain.html#elementsIOThreadsAllocation
>> [2] 
>> http://blog.vmsplice.net/2013/03/new-in-qemu-14-high-performance-virtio.html
>
> I will update the blog post (from 2013) with the modern libvirt XML
> syntax.
>
> Please use the
> https://libvirt.org/formatdomain.html#elementsIOThreadsAllocation
> documentation (unless you are using a really old QEMU and libvirt!).

I have tried the old libvirt XML way in your blog with QEMU v2.2.0 and
Libvirt v1.2.2. It seems that everything works well for me. I will try
the modern libvirt XML syntax with latest QEMU and libvirt.

Thank you,
Weiwei Jia