[vfio-users] threadripper slowness

[Roger Lawhorn]

Just a note:
So far to resolve this I have had to use the kernel boot line options 
"rcu_nocbs=0-23 processor.max_cstate=5".
This fixes a known hardware bug in ryzen cpus that leads to constant 
crashing in linux.
I also compiled qemu 4.1.0-rc4.
Though it seems better I still suffer severe lag during heavy loading of 
textures and 3d objects.
The test games are fallout 4 and fallout 76.
The virtual machine is stored on a 1tb intel ssd.
On a 4 core i7 4940mx it was perfect.
On my new 12 core threadripper it lags out.
As long as the game isnt loading anything new it runs fine.
I never tweaked 'numa' before and I don't see why i need to now.

Any ideas?


I am on this till it works or I am out $3000.


On 8/12/19 6:56 AM, Roger Lawhorn wrote:
>
>
> On 8/11/19 9:59 PM, gamanakis at gmail.com wrote:
>> You could probably get rid of all the lag you experience. Possibly qemu 4.0
>> provides better topology to the guest. Generally Threadripper CPUs have 2
>> NUMA nodes, and you would want to pin the vcpus of the guest to one NUMA
>> node, and also allocate RAM from the same NUMA node. You would also have to
>> make sure the passthrough devices sit on corresponding PCIe lanes which that
>> NUMA node controls. There is lots of good info in reddit.com/r/vfio. Please
>> also provide your xml file (or script), and what you use as a virtualized
>> hard drive. Is it a passthrough NVMe, or virtio-scsi? In the latter case you
>> should also pin iothreads on the same NUMA node as everything else.
>> You can see the topology and NUMA nodes of your cpu by running lstopo.
>>
>> I am eager to see a configuration that uses both NUMA nodes of a
>> Threadripper CPU in one guest with minimal latency.
>>
>>> -----Original Message-----
>>> From:vfio-users-bounces at redhat.com  <vfio-users-bounces at redhat.com>
>>> On Behalf Of Roger Lawhorn
>>> Sent: Sunday, August 11, 2019 9:31 PM
>>> To:vfio-users at redhat.com
>>> Subject: Re: [vfio-users] threadripper slowness
>>>
>>> Hello,
>>>
>>> Just wanted to mention that I got rid of a lot of the lag by compiling
>> qemu 4.0.
>>> I dod not know if its a threadripper issue or not.
>>> The lag directly coincides with hard drive access.
>>> No hard drive access, no game lag.
>>> I have redhat virtio drivers installed for the hard drive and the nic.
>>> Are these drivers intel only?
>>> They are left only from my i7-4940mx processor install.
>>>
>>>
>>> On 8/9/19 11:51 AM, Roger Lawhorn wrote:
>>>> Hello.
>>>> I am new to the list.
>>>> I have been doing gpu passthrough for almost 5 years now with a i7
>>>> 4940mx cpu on a msi gt70 laptop.
>>>>
>>>> My new PC build is:
>>>> MSI x399 carbon pro motherboard : bios xxxxxx.1c0 : svm=enabled:
>>>> iommu=enabled
>>>> Threadripper 2920 12 core
>>>> Radeon pro duo R9 Fury X
>>>> Nvidia 980 TI OC
>>>>
>>>> I was unable to passthrough the nvidia card due to it not getting past
>>>> the "Running option rom..." message when debugging.
>>>>
>>>> The Radeon passed through with flying colors.
>>>>
>>>> The issue:
>>>> I used the radeon to run triple A games in linux using steam for linux
>>>> and proton. No problems.
>>>>
>>>> In Windows 7 in qemu I have passed all 24 cpus to it.
>>>> They max out to 80% while playing the same triple A games and the
>>>> games lag.
>>>> I have never had this issue before.
>>>>
>>>> Admittedly I am using the same script I used on the i7 to get going.
>>>> I had to remove threads from the -smp switch and use cores only.
>>>>
>>>> I also removed the kvm=off which is used for nvidia cards.
>>>>
>>>> I am looking for links to articles or direct info on what to do to
>>>> optimize the cpus.
>>>> When not lagging the radeon performs extremely well.
>>>>
>>>> I am concerned that perhaps kvm is not being used.
>>>>
>>>>
>>>> Thanks
>>>>
>>>> _______________________________________________
>>>> vfio-users mailing list
>>>> vfio-users at redhat.com
>>>> https://www.redhat.com/mailman/listinfo/vfio-users
>>>>
>>> _______________________________________________
>>> vfio-users mailing list
>>> vfio-users at redhat.com
>>> https://www.redhat.com/mailman/listinfo/vfio-users
>
>
> _______________________________________________
> vfio-users mailing list
> vfio-users at redhat.com
> https://www.redhat.com/mailman/listinfo/vfio-users

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/vfio-users/attachments/20190814/d8bb3fce/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lstopo_429.png
Type: image/png
Size: 40567 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/vfio-users/attachments/20190814/d8bb3fce/attachment.png>