Hi,
There are a lot of messages/threads out there about bad performance
while using AMDs Ryzen with KVM GPU passthrough. It revolves all on
enabling/disabling npt, while enabled overall VM performance is nice but
the GPU performance gives me about 20% (and a lot of drops to zero GPU
usage, wh
Although not related to graphics card performance, there is definitely
another issue with regards to running KVM nested L2 guests when npt=1.
Thought I'd mention this in case it helps with identifying performance
issues with NPT.
I'm unable to start any L2 guests with KVM acceleration (--enable-k
Hi,
I realize this is an older thread but I have spent much of today trying
to
diagnose the problem.
I have discovered how to reliably reproduce the problem with very little
effort.
It seems that reproducing the issue has been hit and miss for people as
it seems
to primarily affect games/pr
On Wed, May 3, 2017 at 10:37 AM, Matthias Ehrenfeuchter wrote:
> Hi,
>
> There are a lot of messages/threads out there about bad performance while
> using AMDs Ryzen with KVM GPU passthrough. It revolves all on
> enabling/disabling npt, while enabled overall VM performance is nice but the
> GPU pe
I recognized (with npt disabled) the VM is getting slower over time,
like in Windows the system process is taking more and more CPU usage. A
soft restart does help makeing it "usable" again. Also wondering if this
is an hardware related issue in Ryzen, so the upcoming Naples does have
it too? T
On Wed, 3 May 2017 12:28:35 -0400
Nick Sarnie wrote:
> On Wed, May 3, 2017 at 10:37 AM, Matthias Ehrenfeuchter
> wrote:
> > Hi,
> >
> > There are a lot of messages/threads out there about bad performance while
> > using AMDs Ryzen with KVM GPU passthrough. It revolves all on
> > enabling/disabl
On Fri, May 5, 2017 at 1:27 PM, Alex Williamson
wrote:
> On Wed, 3 May 2017 12:28:35 -0400
> Nick Sarnie wrote:
>
>> On Wed, May 3, 2017 at 10:37 AM, Matthias Ehrenfeuchter
>> wrote:
>> > Hi,
>> >
>> > There are a lot of messages/threads out there about bad performance while
>> > using AMDs Ryz
On 6/25/17 12:55, Nick Sarnie wrote:
On Fri, May 5, 2017 at 1:27 PM, Alex Williamson
wrote:
On Wed, 3 May 2017 12:28:35 -0400
Nick Sarnie wrote:
On Wed, May 3, 2017 at 10:37 AM, Matthias Ehrenfeuchter wrote:
Hi,
There are a lot of messages/threads out there about bad performance while
u
On Wed, Jun 28, 2017 at 1:23 PM, Suravee Suthikulpanit
wrote:
>
>
> On 6/25/17 12:55, Nick Sarnie wrote:
>>
>> On Fri, May 5, 2017 at 1:27 PM, Alex Williamson
>> wrote:
>>>
>>> On Wed, 3 May 2017 12:28:35 -0400
>>> Nick Sarnie wrote:
>>>
On Wed, May 3, 2017 at 10:37 AM, Matthias Ehrenfeucht
On Thu, 29 Jun 2017 00:23:20 +0700
Suravee Suthikulpanit wrote:
> So, I'm trying to reproduce this issue on the Ryzen system w/ the following
> setup:
>
>* Host kernel v4.11 (with this patch https://lkml.org/lkml/2017/6/23/295)
>
>* guest VM RHEL7.3
>
>* guest graphic driver = rade
On 6/29/17 00:26, Steven Walter wrote:
So, I'm trying to reproduce this issue on the Ryzen system w/ the following
setup:
* Host kernel v4.11 (with this patch https://lkml.org/lkml/2017/6/23/295)
* guest VM RHEL7.3
* guest graphic driver = radeon
* qemu-system-x86_64 --version
Q
On Thu, 29 Jun 2017 01:53:57 +0700
Suravee Suthikulpanit wrote:
> On 6/29/17 00:26, Steven Walter wrote:
> >> So, I'm trying to reproduce this issue on the Ryzen system w/ the following
> >> setup:
> >>
> >> * Host kernel v4.11 (with this patch https://lkml.org/lkml/2017/6/23/295)
> >>
> >> *
From: Alex Williamson
Sent: June 28, 2017 3:08 PM
To: Suthikulpanit, Suravee
Cc: Steven Walter; Nick Sarnie; Paolo Bonzini;
iommu@lists.linux-foundation.org; Matthias Ehrenfeuchter; k...@vger.kernel.org;
Bridgman, John
Subject: Re: AMD Ryzen KVM/NPT/IOMMU issue
From: Alex Williamson
Sent: June 28, 2017 3:08 PM
To: Suthikulpanit, Suravee
Cc: Steven Walter; Nick Sarnie; Paolo Bonzini;
iommu@lists.linux-foundation.org; Matthias Ehrenfeuchter; k...@vger.kernel.org;
Bridgman, John
Subject: Re: AMD Ryzen KVM/NPT/IOMMU issue
On Thu, 29 Jun 2017 01:53
gt; To: Suthikulpanit, Suravee
> Cc: Steven Walter; Nick Sarnie; Paolo Bonzini;
> iommu@lists.linux-foundation.org; Matthias Ehrenfeuchter;
> k...@vger.kernel.org; Bridgman, John
> Subject: Re: AMD Ryzen KVM/NPT/IOMMU issue
>
> On Thu, 29 Jun 2017 01:53:57 +0700
> Suravee Suthikulp
On 28/06/2017 21:52, Graham Neville wrote:
> Although not related to graphics card performance, there is definitely
> another issue with regards to running KVM nested L2 guests when npt=1.
>
> Thought I'd mention this in case it helps with identifying performance
> issues with NPT.
>
> I'm unab
On Wed, Jun 28, 2017 at 4:33 PM, Paolo Bonzini wrote:
>
>
> On 28/06/2017 21:52, Graham Neville wrote:
>> Although not related to graphics card performance, there is definitely
>> another issue with regards to running KVM nested L2 guests when npt=1.
>>
>> Thought I'd mention this in case it helps
On Wed, Jun 28, 2017 at 7:34 PM, Nick Sarnie wrote:
> Hi Suravee,
>
> Thanks a lot for helping. Torcs does not appear graphically demanding
> on modern hardware, so this issue may not be easily noticeable. I was
> able to easily reproduce the problem using the Unigine Heaven
> benchmark, but I'm s
On Wed, Jun 28, 2017 at 9:50 PM, Thiago Padilha wrote:
> Some more data from 3DMark benchmarks:
>
> Time Spy(DirectX 12):
> - Graphics test 1:
> - npt=0: 37.65 FPS
> - npt=1: 24.22 FPS (36% drop)
> - Graphics test 2:
> - npt=0: 33.05 FPS
> - npt=1: 29.65 FPS (10% drop)
> - CPU test:
> -
Some more data from 3DMark benchmarks:
Time Spy(DirectX 12):
- Graphics test 1:
- npt=0: 37.65 FPS
- npt=1: 24.22 FPS (36% drop)
- Graphics test 2:
- npt=0: 33.05 FPS
- npt=1: 29.65 FPS (10% drop)
- CPU test:
- npt=0: 17.35 FPS
- npt=1: 12.03 FPS (31% drop)
Fire Strike(DirectX 11):
-
Hi
Just wanted to add that I've also tested passthrough with Xen and my radeon
rx460(unfortunately Xen doesn't work with nvidia yet) and confirm that hardware
assisted paging seems to work flawless without affecting GPU performance.
An easy way to verify this is to run the following Passmark's Pe
On Wed, Jun 28, 2017 at 2:53 PM, Suravee Suthikulpanit
wrote:
>
>
> On 6/29/17 00:26, Steven Walter wrote:
>>>
>>> So, I'm trying to reproduce this issue on the Ryzen system w/ the
>>> following
>>> setup:
>>>
>>> * Host kernel v4.11 (with this patch
>>> https://lkml.org/lkml/2017/6/23/295)
>>>
Further to this I have verified that IOMMU is working fine, traces and
additional printk's added to the kernel module were used to check. All
accesses are successful and hit the correct addresses.
However profiling under Windows shows there might be an issue with IRQs
not reaching the guest. When
I have identified the issue! With NPT enabled I am now getting near bare
metal performance with PCI pass through. The issue was with some stubs
that have not been properly implemented. I will clean my code up and
submit a patch shortly.
This is a 10 year old bug that has only become evident with
I have isolated it to a single change, although I do not completely
understand what other implications it might have.
By just changing the line in `init_vmcb` that reads:
save->g_pat = svm->vcpu.arch.pat;
To:
save->g_pat = 0x0606060606060606;
This enables write back and performance jumps
On Wed, 25 Oct 2017 07:16:46 +1100
geoff--- via iommu wrote:
> I have isolated it to a single change, although I do not completely
> understand what other implications it might have.
>
> By just changing the line in `init_vmcb` that reads:
>
>save->g_pat = svm->vcpu.arch.pat;
>
> To:
>
>
On 2017-10-25 08:31, Alex Williamson wrote:
On Wed, 25 Oct 2017 07:16:46 +1100
geoff--- via iommu wrote:
I have isolated it to a single change, although I do not completely
understand what other implications it might have.
By just changing the line in `init_vmcb` that reads:
save->g_pat =
On Tue, Oct 24, 2017 at 5:39 PM, geoff--- via iommu
wrote:
> On 2017-10-25 08:31, Alex Williamson wrote:
>>
>> On Wed, 25 Oct 2017 07:16:46 +1100
>> geoff--- via iommu wrote:
>>
>>> I have isolated it to a single change, although I do not completely
>>> understand what other implications it might
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