[vfio-users] threadripper slowness
Roger Lawhorn
rll at twc.com
Thu Aug 15 16:14:11 UTC 2019
It is resolved.
windows 7 could not handle my new cpu.
I had a windows 10 virt machine I never used.
Booted it up and all is fixed.
I guess its finally goodbye to windows 7.
Goodbye old friend.
I'd say the issue was an OS that was out of date.
On 8/14/19 10:49 PM, Rich Mingin (vfio-users) wrote:
> You need to tweak NUMA because your previous CPU was not NUMA, and
> your new one is. Having the VM running on some CPU cores on one
> physical package, but accessing ram that's attached to other CPU cores
> on a different package can cause a lot of overhead. You want to avoid
> that.
>
> On Wed, Aug 14, 2019 at 7:31 PM Roger Lawhorn <rll at twc.com
> <mailto:rll at twc.com>> wrote:
>
> 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
>> <mailto: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 inreddit.com/r/vfio <http://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 <mailto:vfio-users-bounces at redhat.com> <vfio-users-bounces at redhat.com> <mailto: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 <mailto: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 <mailto:vfio-users at redhat.com>
>>>>> https://www.redhat.com/mailman/listinfo/vfio-users
>>>>>
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