4 ms·

Hypervisor overhead should be low, https://www.howtogeek.com/does-windows-11-vbs-slow-pc-games/ https://www.howtogeek.com/does-windows-11-vbs-slow-pc-games/ Wh

Hypervisor overhead should be low, https://www.howtogeek.com/does-windows-11-vbs-slow-pc-games/ https://www.howtogeek.com/does-windows-11-vbs-slow-pc-games/ What kind of workloads have noticeably lower performance with VBS?

kookamamie 1y ago
We're working on HPC / graphics / computer-vision software and noticed a particularly nasty issue with VBS enabled just last week. Although, have to be mentioned it was on Win10 Pro.
- kachapopopow 1y ago
  This most likely comes from IOMMU - disable it.
  - jychang 1y ago
    That’d break a lot of GPU setups
    - kachapopopow 1y ago
      Only if you want to virtualize it or have vms, for VBS it simply disables hardware pcie memory space isolation. (With IOMMU on, each pcie device gets an isolated memory buffer).
jeroenhd 1y ago
It was measured to have a performance impact of up to 10%, with even higher numbers for the nth percentile lows: https://www.tomshardware.com/news/windows-vbs-harms-performance-rtx-4090 https://www.tomshardware.com/news/windows-vbs-harms-performa... Overhead should be minimal but something is preventing it from working as well as it theoretically should. AFAIK Microsoft has been improving VBS but I don't think it's completely fixed yet. BF6 requiring VBS (or at least "VBS capable" systems) will probably force games to find a way to deal with VBS as much as they can, but for older titles it's not always a bad idea to turn off VBS to get a less stuttery experience.
- UltraSane 1y ago
  VBS requires hyper-v to be enabled and it "owns" the CPU virtualization hardware so I can't use VMware workstation which is very annoying.
  - davikr 1y ago
    Same. Have to disable VBS for VirtualBox, and it gets more and more obscure with each update because some features like Windows Hello force it back on.
  - bpye 1y ago
    VMWare Workstation [0] (and I thought VirtualBox - though I can't find any official docs [1]) should be able to use the Hyper-V hypervisor via WHP. QEMU can also use WHP via --accel whpx. [0] - https://techcommunity.microsoft.com/blog/virtualization/vmware-workstation-and-hyper-v/1419928 https://techcommunity.microsoft.com/blog/virtualization/vmwa... [1] - https://www.impostr-labs.com/use-hyper-v-and-virtualbox-together-on-server-2019/ https://www.impostr-labs.com/use-hyper-v-and-virtualbox-toge...
    - deburo 1y ago
      It works indeed, but the performance drop is quite drastic.
    - UltraSane 1y ago
      As a network engineer I mainly like VMware workstation because of its awesome virtual network editor that lets me easily build complex topologies but it doesn't work when you use Hyper-V.
- malkia 1y ago
  BF6 requires this? Is there any official article/link about this? Thank you!
  - password4321 1y ago
    The closest so far (I don't know the specifics of VBS vs. Secure Boot): https://news.ycombinator.com/item?id=44805565 https://news.ycombinator.com/item?id=44805565 Secure Boot is a requirement to play Battlefield 6 on PC > It's the Javelin Anti cheat system which forces the use of secure boot

kookamamie 1y ago

We're working on HPC / graphics / computer-vision software and noticed a particularly nasty issue with VBS enabled just last week. Although, have to be mentioned it was on Win10 Pro.

kachapopopow 1y ago
This most likely comes from IOMMU - disable it.
- jychang 1y ago
  That’d break a lot of GPU setups
  - kachapopopow 1y ago
    Only if you want to virtualize it or have vms, for VBS it simply disables hardware pcie memory space isolation. (With IOMMU on, each pcie device gets an isolated memory buffer).

jeroenhd 1y ago

It was measured to have a performance impact of up to 10%, with even higher numbers for the nth percentile lows: https://www.tomshardware.com/news/windows-vbs-harms-performance-rtx-4090 https://www.tomshardware.com/news/windows-vbs-harms-performa... Overhead should be minimal but something is preventing it from working as well as it theoretically should. AFAIK Microsoft has been improving VBS but I don't think it's completely fixed yet. BF6 requiring VBS (or at least "VBS capable" systems) will probably force games to find a way to deal with VBS as much as they can, but for older titles it's not always a bad idea to turn off VBS to get a less stuttery experience.

UltraSane 1y ago
VBS requires hyper-v to be enabled and it "owns" the CPU virtualization hardware so I can't use VMware workstation which is very annoying.
- davikr 1y ago
  Same. Have to disable VBS for VirtualBox, and it gets more and more obscure with each update because some features like Windows Hello force it back on.
- bpye 1y ago
  VMWare Workstation [0] (and I thought VirtualBox - though I can't find any official docs [1]) should be able to use the Hyper-V hypervisor via WHP. QEMU can also use WHP via --accel whpx. [0] - https://techcommunity.microsoft.com/blog/virtualization/vmware-workstation-and-hyper-v/1419928 https://techcommunity.microsoft.com/blog/virtualization/vmwa... [1] - https://www.impostr-labs.com/use-hyper-v-and-virtualbox-together-on-server-2019/ https://www.impostr-labs.com/use-hyper-v-and-virtualbox-toge...
  - deburo 1y ago
    It works indeed, but the performance drop is quite drastic.
  - UltraSane 1y ago
    As a network engineer I mainly like VMware workstation because of its awesome virtual network editor that lets me easily build complex topologies but it doesn't work when you use Hyper-V.
malkia 1y ago
BF6 requires this? Is there any official article/link about this? Thank you!
- password4321 1y ago
  The closest so far (I don't know the specifics of VBS vs. Secure Boot): https://news.ycombinator.com/item?id=44805565 https://news.ycombinator.com/item?id=44805565 Secure Boot is a requirement to play Battlefield 6 on PC > It's the Javelin Anti cheat system which forces the use of secure boot