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Re: [vfio-users] Speed tips requested

Do you pass your USB keyboard or do you use emulated keyboard and one of QXL windows to grab/release focus? I use the second option and I had to follow the steps from the following link to deal with performance proplems with key repeats:

On Sat, Mar 25, 2017 at 10:51 AM, Patrick O'Callaghan <poc usb ve> wrote:
I'm running Windows 10 in a KVM/QEMU VM under Fedora 25. The host is a
16GB i3770 and I have 4 threads (2 cores) dedicated to the VM with CPU
pinning and 8GB hugepages. The passthrough GPU is an Nvidia Geforce GTX

The guest disk is a 100GB raw file under vfio. The host disk is a 1TB
Toshiba SATA 2.

This generally works quite well, except for two things:

1) KB events seem to overrun in games, i.e. there is stuttering and a
buzz when holding down a key for too long. Keyboard and mouse are
wireless Logitech hardware on a USB-2 port.

Initially I had configured USB-2 on the VM and in an effort to fix this
changed it to USB-3, which seemed to make it slightly faster but not go
away (nb: this is still on the same physical USB-2 port).

I then attempted to enable MSI as outlined in https://vfio.blogspot.co.
uk/2014/09/vfio-interrupts-and-how-to-coax-windows.html. After the USB-
3 change (see above) Windows now shows the USB-3 controller as using
MSI, however the Windows Nvidia drivers don't seem to support it, even
after registry editing. Note that the GPU hardware does support it
according to Linux ('lspci -v -s <id>').

2) There is quite frequent (every few seconds) visual stuttering --
pause then continue -- when moving rapidly through a rendered scene,
possibly caused by disk I/O.

I'm already using vfio. Would vfio-scsi make a difference? Should I be
thinking about a dedicated disk?

Thanks for any hints.


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