On 2016年07月26日 15:48, Yan Fridland wrote:
Hi Yadi,
Thanks a lot for your comment.
Actually I am doing emulator pin to the QEMU process in the XML:
<vcpu placement='static'>3</vcpu>
<cputune>
<vcpupin vcpu='0' cpuset='1'/>
<vcpupin vcpu='1' cpuset='2'/>
<vcpupin vcpu='2' cpuset='3'/>
<emulatorpin cpuset='8'/>
<vcpusched vcpus='1-2' scheduler='fifo' priority='99'/>
</cputune>
*BUT*, looks like it doesn’t help. Is there any way to make ALL the
related QEMU threads run within the scope of cores 1,2,3,8 *ONLY* in
the above example?
it is so wired, I have no better ways to handle it since I have no
experienced the similar issue as your. so, just two suggestion for you:
1: check all qemu thread associated entries under cgroup filesystem,
sure that cpusets are correctly set.
2: if 1 fails, it may means there is nothing left to do, ftrace for
schduler.
whatever result, let me know please. I am very interesting in the issue.
Yadi
Thanks,
Yan
*From:*Yadi [mailto:yadi...@windriver.com]
*Sent:* Tuesday, July 26, 2016 6:12 AM
*To:* Yan Fridland; qemu-discuss@nongnu.org
*Subject:* Re: [Qemu-discuss] [problem]-starting a VM causes RT
(latency) problem for application running on another VM
On 2016年07月25日 23:03, Yan Fridland wrote:
Hello All,
Here is a problem I saw when I ran virsh start to a VM.
I have 2VMs on a server when one of them is running a RT
application and the other is in shut down state. Then I executed
"virsh start" to the second VM and saw 2-3 seconds later a big
latency problem in my RT application running on the first VM.
I want to emphasize that the VMs use dedicated isolated cores of
the server and I have the relevant configuration on the server and
the vcpu pinning section of virsh xml.
Can anyone tell me why I experience such behavior and how it can
be resolved?
I will highly appreciate your help.
Thank you,
Yan
I am not very sure, but I suggest you to add emulatorpin in xml file,
then see results. actually, all qemu associated process can use all
processors via cgroup configure created by libvirt,
https://libvirt.org/formatdomain.html#elementsCPUTuning
