New: kvm_amd nested pagetable gpu passthrough performance oddities
https://bugzilla.kernel.org/show_bug.cgi?id=196409
Bug ID: 196409
Summary: kvm_amd nested pagetable gpu passthrough performance
oddities
Product: Virtualization
Version: unspecified
Kernel Version: 4.10.8-1
Hardware: x86-64
OS: Linux
Tree: Mainline
Status: NEW
Severity: high
Priority: P1
Component: kvm
Assignee: [email protected]
Reporter: [email protected]
Regression: NoThe hardware I was testing with:
AMD Ryzen R7 1700
Gigabyte GA-AX370-Gaming 5
different GPUs
Windows10 x64 Guest
But this bug is reproducable on AMD FX series too.
While community is discussing for a while about this bug, I haven't found it here. Based on our discussion here:
http://www.spinics.net/lists/kvm/msg149446.html
While npt is enabled a passed through GPU is giving much less performance as expected. Here some test results the community already did:
First Heaven benchmark with ultra settings on 1920x1080:
- DirectX 11:
- npt=0: 87.0 fps
- npt=1: 78.4 fps (10% drop)
- DirectX 9:
- npt=0: 100.0 fps
- npt=1: 66.4 fps (33% drop)
- OpenGL:
- npt=0: 82.5 fps
- npt=1: 35.2 fps (58% drop)
Heaven Benchmark again, this time with low settings on 1280x720:
- DirectX 11:
- npt=0: 182.5 fps
- npt=1: 140.1 fps (25% drop)
- DirectX 9:
- npt=0: 169.2 fps
- npt=1: 74.1 fps (56% drop)
- OpenGL:
- npt=0: 202.8 fps
- npt=1: 45.0 fps (78% drop)
PerformanceTest 9.0 3d benchmark:
- DirectX 9:
- npt=0: 157 fps
- npt=1: 13 fps (92% drop)
- DirectX 10:
- npt=0: 220 fps
- npt=1: 212 fps (4% drop)
- DirectX 11:
- npt=0: 234 fps
- npt=1: 140 fps (40% drop)
- DirectX 12:
- npt=0: 88 fps (scored 35 because of the penalized FPS of not being
able to run at 4k)
- npt=1: 4.5 fps (scored 1, 95% drop)
- GPU Compute:
- Mandel:
- npt=0: ~= 2000 fps
- npt=1: ~= 2000 fps
- Bitonic Sort:
- npt=0: ~= 153583696.0 elements/sec
- npt=1: ~= 106233376.0 elements/sec (31% drop)
- QJulia4D:
- npt=0: ~= 1000 fps
- npt=1: ~= 1000 fps
- OpenCL:
- npt=0: ~= 750 fps
- npt=1: ~= 220 fps
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):
- Graphics test 1:
- npt=0: 80.56 FPS
- npt=1: 41.89 FPS (49% drop)
- Graphics test 2:
- npt=0: 70.64 FPS
- npt=1: 60.75 FPS (14% drop)
- Physics test:
- npt=0: 50.14 FPS
- npt=1: 5.78 FPS (89% drop)
- Combined test:
- npt=0: 32.83 FPS
- npt=1: 17.70 FPS (47% drop)
Sky Diver(DirectX 11):
- Graphics test 1:
- npt=0: 248.81 FPS
- npt=1: 173.63 FPS (31% drop)
- Graphics test 2:
- npt=0: 250.49 FPS
- npt=1: 124.84 FPS (51% drop)
- Physics test:
- 8 threads:
- npt=0: 140.93 FPS
- npt=1: 119.08 FPS (15% drop)
- 24 threads:
- npt=0: 110.22 FPS
- npt=1: 74.55 FPS (33% drop)
- 48 threads:
- npt=1: 71.56 FPS
- npt=1: 45.93 FPS (36% drop)
- 96 threads:
- npt=0: 41.04 FPS
- npt=1: 24.81 FPS (40% drop)
- Combined test:
- npt=0: 75.65 FPS
- npt=1: 50.45 FPS (33% drop)
I compared the performance with XEN and found out there is no performance impact, so the bug should be in the nested pagetable implementation in kvm_amd module and not a hardware related issue in AMD-Vi.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
https://bugzilla.kernel.org/show_bug.cgi?id=196409
Michael ([email protected]) changed:
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--- Comment #1 from Michael ([email protected]) ---
I too have this NPT issue with Ryzen 1800x and KVM latest kernel. It's incredible that no-one has managed to resolve this yet.
GPU performance is absolutely dire with npt=1 and CPU is so bad with npt=0. So loss/loss situation.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Thomas ([email protected]) changed:
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--- Comment #2 from Thomas ([email protected]) ---
Please look into this well documented issue, it makes the new AMD platform very unattractive for advanced virtualization.
This is very unfortunate because the nature of Ryzen (many cores, competitive IPC, good value, inofficial ECC support) would be excellent for this.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
[email protected] changed:
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--- Comment #3 from [email protected] ---
I'm also having this issue.
AMD Ryzen R7 1700
Asus Prime B350-Plus
Nvidia 970
Host: Arch Linux Kernel 4.11.9
Guest: Windows 10 x64
Adding to the info collected by efeu seems like the bug isn't specific to Ryzen.
The first bug report is 9 years old.
https://sourceforge.net/p/kvm/bugs/230/
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
[email protected] changed:
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--- Comment #4 from [email protected] ---
Same problem here.
AMD Ryzen R7 1700
Gigabyte GA-AX370-Gaming 5
GT 570
R9 290x
Host: Arch
Guest: Windows 8.1/10
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #5 from Andrey ([email protected]) --- Confirmed with:
AMD Ryzen 5 1600
Gigabyte AB350 Gaming 3
GTX 750 for host
GTX 1050 Ti for guest
Arch Linux as a host, Windows 10 as a guest.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #6 from Michael ([email protected]) --- Threadripper just around the corner and noone here knows the answer to the KVM/NPT/AMD issue. Shame really, I think quite a few folk will switch to Intel if this isn't fixed soon.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
[email protected] changed:
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--- Comment #7 from [email protected] ---
Same issue with kernel 4.10 - 4.12 here.
CPU - AMD Ryzen 7 1700
MB - Asus Prime x370 Pro
Host GPU - NVidia GTX 750ti
VFIO GPU - AMD Radeon RX480
Host OS - Manjaro 17.2
Guest OS - Windows 10
With npt=1, everything is fast, except GPU fps is 10-15 in Skyrim with npt=0, everything is slow, GPU fps is ~30 in Skyrim
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Symon ([email protected]) changed:
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--- Comment #8 from Symon ([email protected]) --- Same Problems here :(
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
JohnSmith ([email protected]) changed:
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--- Comment #9 from JohnSmith ([email protected]) --- Same problem here. This issue should be a very high priority. It basically destroys GPU passthrough on Ryzen CPUs.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
maspe ([email protected]) changed:
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--- Comment #10 from maspe ([email protected]) --- Same problem for me :(
Ubuntu 17.04 - all mainline kernels up to 4.13-rc6
CPU - AMD Ryzen 7 1700
MB - Asus Prime x370 Pro
Host GPU - NVidia GTX 1050ti passthrough GPU - AMD Radeon RX480 Host OS - Ubuntu 17.04
Guest OS - Windows 10
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Duarte Pousa ([email protected]) changed:
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--- Comment #11 from Duarte Pousa ([email protected]) --- Behaviour confirmed in OpenSUSE Tumbleweed, both in the distribution provided kernels and mainline.
Current Kernel Version: 4.12
Tested Kernel Versions: 4.11,4.12
CPU - AMD Ryzen 7 1700
MB - MSI x370 SLI PLUS PRO
Host GPU - AMD Radeon RX 560
Guest GPU - NVIDIA GTX 750 ti
Host OS - OpenSUSE Tumbleweed
Guest OS - Windows 10 LTSB 2016
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Dennis ([email protected]) changed:
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--- Comment #12 from Dennis ([email protected]) --- I have the same problems.
Current Kernel Version: 4.12.8 Tested Kernel Versions: 4.10, 4.11, 4.12
CPU - AMD Ryzen 7 1700
MB - ASRock X370 Taichi Host GPU - Nvidia GT1030 Guest GPU - Nvidia GTX 980 Ti Host OS - Fedora 26 Workstation Guest OS - Windows 10 Education
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
[email protected] changed:
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--- Comment #13 from [email protected] --- Same problem here
CPU - AMD Ryzen 7 1700
MB - ASRock X370 Killer SLI Host GPU - AMD Radeon HD6850 Guest GPU - Nvidia GTX 1080 Ti Host OS - Fedora 26 Workstation Guest OS - Windows 10 Pro
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
John Kelley ([email protected]) changed:
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--- Comment #14 from John Kelley ([email protected]) ---
I am also experiencing the above mentioned issue with very similar performance impact. I am currently not using the virtualization features due to this performance bug with AMD Nested Page Tables.
CPU - AMD Ryzen 7 1800x
MB - Asus PRIME X370-PRO
Host GPU - AMD Radeon 480
Guest GPU - AMD Radeon r290
Host OS - Arch Linux, 4.11.9 kernel (Previously 4.9, 4.10) Guest OS - Windows 10 Pro Anniversary Edition
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
ML ([email protected]) changed:
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--- Comment #15 from ML ([email protected]) ---
Also the same problem.
CPU - AMD Ryzen 7 1700 & TR 1950X
MB - Gigabyte Gaming 5 & Asrock X399 Fatality Pro
Host GPU - AMD RX 570 & RX 460
Guest GPU - Nvidia 980Ti & 1080ti
Host OS - Fedora 26 Workstation
Guest OS - Windows 10 Pro
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
sddearjack ([email protected]) changed:
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--- Comment #16 from sddearjack ([email protected]) --- Had to reply, affected by the same problem, annoying as hell, because I cant find a solution or how to adapt to this *bug.
CPU: R7 1700x
MB: X370 Taichi
Host GPU: RX 550
Guest GPU: 980 ti
Host OS: Gentoo, Arch, Fedora.
Guest OS: Windows 10 Pro
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
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EPalmer ([email protected]) changed:
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--- Comment #17 from EPalmer ([email protected]) --- I'm also having this issue, currently still using my old machine in the meantime.
CPU: Ryzen 1700 MB: Gigabyte X370 Gaming 5 Host GPU: Radeon 7870 (PITCAIRN) Guest GPU: Radeon 290X (HAWAII) Host OS: Ubuntu 16.04 (Kernel 4.11.0-14-generic Ubuntu) Guest OS: Windows 10/Windows 8.1/Windows 7
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Iwanovich ([email protected]) changed:
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--- Comment #18 from Iwanovich ([email protected]) --- Dealing with the same problem here.
CPU - AMD Ryzen 5 1600
Motherboard - Gigabyte AX370 Gaming 5 Host GPU - MSI Nvidia GT710 2GB Guest GPU - Gainward Nvidia GTX 1050Ti 4GB Host OS - Fedora 26, kernel 4.12.8. Guest OS - Microsoft Windows 10
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Tiit ([email protected]) changed:
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--- Comment #19 from Tiit ([email protected]) ---
Dealing with the exact same problem here.
CPU - AMD Ryzen 7 1700X
Motherboard - MSI X370 Gaming Carbon Pro
Host GPU - Any Random GPU
Guest GPU - MSI GTX 1080
Host OS - Fedora 26, kernel 4.13
Guest OS - Microsoft Windows 10
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Fruhwirth Clemens ([email protected]) changed:
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--- Comment #20 from Fruhwirth Clemens ([email protected]) --- For a fix, I am publicly offering a bounty expiring 2017/11/01 of 0.02 Bitcoin (~100$ at the current price) redeemable by the person on the respective git commit.
Maybe a good starting point is grepping through the code for "npt_enabled" and doing some random guesswork, and/or introducing more performance counter at host or guest to increase visibility. Maybe we can take apart a benchmark and identity the operation that is slow.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #21 from Andrey ([email protected]) --- (In reply to Fruhwirth Clemens from comment #20)
Quoted 4 lines
For a fix, I am publicly offering a bounty expiring 2017/11/01 of 0.02 Bitcoin (~100$ at the current price) redeemable by the person on the respective git commit.
Another $100 from me.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Allison ([email protected]) changed:
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--- Comment #22 from Allison ([email protected]) --- (In reply to Fruhwirth Clemens and Andrey from comment #20-21)
Quoted 5 lines
Quoted 3 lines
For a fix, I am publicly offering a bounty expiring 2017/11/01 of 0.02 Bitcoin (~100$ at the current price) redeemable by the person on the respective git commit.
Another $100 from me.
Another $25 from me.
In bitcoin that is, and sorry I couldn't give more. Will update if I can get more.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Paolo Bonzini ([email protected]) changed:
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--- Comment #23 from Paolo Bonzini ([email protected]) --- Guys, stop spamming the bug. AMD is looking at it.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #24 from efeu ([email protected]) ---
(In reply to Paolo Bonzini from comment #23)
Quoted 1 line
Guys, stop spamming the bug. AMD is looking at it.
Source?
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #25 from efeu ([email protected]) ---
@Paolo
There is neither an official AMD statemant nor a confirmation on this issue. You have spoken to an AMD developer? What they told you?
I mean the only thing beeing of interest is how long it will take to be fixed 1 month?, 1 year?, another 10 years?, never?
I mean this issue is not only about GPU passthrough, all PCI-E devices I've tested are affected, those are:
-SATA-Storage-/SAS-Raid-Controller-Cards (slow-downs/hangs in transfer) -PCI-E SSDs (slow-downs/hangs in transfer)
-Network-Cards (slow-downs/hangs in transfer)
-TV-Cards (hangs in (hardware decoded) streams)
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
[email protected] changed:
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--- Comment #26 from [email protected] ---
(In reply to efeu from comment #24)
Quoted 4 lines
(In reply to Paolo Bonzini from comment #23)
Quoted 1 line
Guys, stop spamming the bug. AMD is looking at it.
Source?
I guess this one https://community.amd.com/thread/215931. I saw an id "ray_m" with the AMD logo and the title "Technical Support Engineer" replied "We are researching the issue ..." several months ago.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #27 from efeu ([email protected]) ---
Well this is my thread on the AMD board and I have talked to ray_m directly, he "escalated" the issue, that's it. But ray_m did not receive anything from his developers, so this suggests on "noone is working on this issue" to me.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #28 from sddearjack ([email protected]) --- Main concern is it software or hardware side. Some sources tell that Nested page tables performance(AMD) is 10 years old *bug. So they are unable to fix it, someone is being paid by someone not to look in this problem, not a major problem for consumer market?
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #29 from Dennis ([email protected]) --- (In reply to sddearjack from comment #28)
Quoted 4 lines
Main concern is it software or hardware side. Some sources tell that Nested page tables performance(AMD) is 10 years old *bug. So they are unable to fix it, someone is being paid by someone not to look in this problem, not a major problem for consumer market?
Since there doesn't seem to a problem in Xen or ESXi, doesn't that point to a software problem?
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #30 from efeu ([email protected]) ---
We already know that this is in kvm_amd module.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
Fawwal ([email protected]) changed:
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--- Comment #31 from Fawwal ([email protected]) ---
Came here to give my support for this. Looking to make one box to do it all. I think Ryzen is a perfect choice. I'm going to hold off for now, wait a few months for a solution. If ya'll think it will take longer to find a solution than that I may just go for a typical two processor xenon build if no one can find a solution in my time frame.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
badOne ([email protected]) changed:
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--- Comment #32 from badOne ([email protected]) ---
I also noticed heavy performance loss with my Ryzen 1700X and KVM. Disabling npt completely is no option either, it justs slows down the CPU a ton (which totally makes sense)
My specs are:
- Ryzen 1700X
- ASUS Prime x370 Pro
- GPU0: GTX 1050 (host)
- GPU1: GTX 1070 (guest)
I also experimented with CPU pinning, mounting a whole SSD instead of just using a virtual disk, trying different drivers, settings, etc.
Nothing of the above seemed to change anything. With npt=1 some games are running fine (e.g. League of Legends), some are running ok (e.g. Path of Exile) and some are running extremely bad (e.g. Player Unknown's Battlegrounds, GTA 5, CS:GO, etc.)
I looked into the code but I'm not able to dive into the project due to the lack of time.
This is a major issue in my opinion and AMD + the guys from KVM should look into this together. Intel got it running, too. In addition with Xen it's working perfectly but I really don't like using Xen, I like KVM a lot more.
Please fix this issue. If help is needed just contact me, I will when time allows it.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
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[email protected] changed:
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--- Comment #33 from [email protected] ---
Came here to give my support for this.
My setup
Ryzen 1700X
MSI x370 gaming pro carbon
GPU0: Asus RX550
GPU1: MSI RX580
Hope this will be fixed soon.
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #34 from Nick Sarnie ([email protected]) --- Hi all,
Just a quick update. A workaround has been found. Please see the following post:
https://lists.linuxfoundation.org/pipermail/iommu/2017-October/024823.html
Please note that this patch is only a workaround, is incorrect in some cases and cannot be merged upstream in this form. But, it's a start and you can make this change locally to workaround the GPU performance hit.
Thanks,
Sarnex
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #35 from Benjamin ([email protected]) --- That is awesome news!
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #36 from Nick Sarnie ([email protected]) --- Another update, a better patch from Paolo is here:
https://marc.info/?l=kvm&m=150891016802546&w=2
Sarnex
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #37 from Nick Sarnie ([email protected]) --- Paolo has submitted a final patch here:
https://patchwork.kernel.org/patch/10027525/
People who put up a bounty should prepare to pay out (to Geoff because Paolo said so) :)
Sarnex
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[Bug 196409] kvm_amd nested pagetable gpu passthrough performance oddities
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=196409
--- Comment #38 from Fruhwirth Clemens ([email protected]) --- As promised, I paid out my bounty here:
https://blockchain.info/tx/91077ba4e7be1ab303b591efa268f194ab186112caa014576a65a26d69eb1dd2
More payout information for geoff@ is posted here:
https://www.reddit.com/r/VFIO/comments/78i3jx/possible_fix_for_the_npt_issue_discussed_on_iommu/doxtwyn/
Thanks again for working on this.
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