{"id":1091,"date":"2022-07-22T12:41:55","date_gmt":"2022-07-22T20:41:55","guid":{"rendered":"https:\/\/angrysysadmins.tech\/?p=1091"},"modified":"2023-09-14T11:23:50","modified_gmt":"2023-09-14T19:23:50","slug":"vfio-tuning-your-windows-gaming-vm-for-optimal-performance","status":"publish","type":"post","link":"https:\/\/angrysysadmins.tech\/index.php\/2022\/07\/grassyloki\/vfio-tuning-your-windows-gaming-vm-for-optimal-performance\/","title":{"rendered":"VFIO: Tuning your Windows gaming VM for optimal performance"},"content":{"rendered":"

This will be a guide on advanced tuning for a VFIO gaming VM. If you’re starting from scratch, read through the Arch Wiki guide on PCI passtrhough via OVMF<\/a>. It is a great starting point and covers all of the basics. I’d recommend using libvirt<\/code> instead of straight QEMU.<\/p>\n

Host hardware configuration<\/h2>\n

Before we begin, it’s best I show and explain my host host specs. If you only want configuration info, jump to Host Configurations<\/a>.<\/p>\n

Distro: Arch Linux\r\nMotherboard: X399 AORUS Gaming 7  \r\nDE: Plasma on X11\r\nCPU: AMD Ryzen Threadripper 2950X OC to @ 4.000GHz \r\nGPUs: Radeon RX 480, Radeon RX6900 XT, Radeon RX 550X\r\nNIC: Intel X520-DA2\r\nSSDs: Samsung 970 pro 512GB (luks encrypted, BTRFS), Team Group MP34 1TB\r\nHDDs: 4x 4TB HGST Deskstar NAS drives in a ZFS RAID-Z1 \r\nMemory: 32GB (4x8GB) Gskill Samsung B-die kit running at 3200 MT\/s XMP<\/pre>\n
For the distro, I chose Manjaro Linux because its basically a few months delayed turn key Arch Linux. This is important because when my rig was built, Threadripper had issues with older linux kernels. Manjaro lets the user easily pick a kernel from a nice and easy to use GUI, very important for new-to-desktop-Linux me. Since its based on Arch, it’s also running the latest packges for QEMU and OVMF, always ensuring the ease of new feature deployment, and with AUR, its really easy to get custom kernels and packages.<\/p>\n
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For the platform, I went with a Threadripper because I wanted to have 64 PCIe lanes for lots of add-in cards, with the added benefit of extra memory slots and NVMe slots. Threadripper is simultaneously a gift with all of its cores and a downside because of its NUMA architecture in the 1st and 2nd gen iterations. NUMA adds extra complexity to the VM, but these days its not too hard with tons of guides working around it. The X399 AORUS Gaming 7 motherboard I chose because I found it for 100 bucks on Amazon because the integrated sound card was broken.<\/p>\n
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For the GPU’s, I initially had a GTX 1080 but swapped it out for a RX6900XT because I wanted to use it in both Linux and Windows. Despite Arch making Nvidia drivers easy, it’s still a pain to work with in Linux. This can be ignored if you just have the GPU for passthrough and nothing else. The other 2 GPU’s are there for display outputs to my array of 6 monitors.<\/p>\n
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The NIC was chosen to take advantage of SR-IOV and Virtual Function NICs for use with the VM. The virtual function NIC allows the complete bypassing of the virtio<\/code> network stack and use of essentially a PCIEe NIC in the VM. This decreases latency and weird kernel lag caused by 10 gbit speeds with the virt-io drivers in windows. I think this issue could have been fixed but I had the NIC anyways so I wanted to try it out and it works great. The way SR-IOV works you can even set a virtual function device to a specific VLAN either in the host or VM.<\/p>\n
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The storage for the host is the Samsung 970. Its fast and reliable. My only regret was not getting the 1TB version. For the guest, I have a Team Group SSD passed through. The HDD array uses ZFS because its just the best file system in the world, but more importantly it has Zvol’s, Encryption, Compression, and a really good cache system with ARC.<\/p>\n
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Host Configurations<\/h1>\n
BIOS\/UEFI<\/h3>\n
Here are the configs I’d turn on if possible<\/p>\n